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kmpres

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2Instructables429,358Views310CommentsTokyo, Japan
Was a maker before makers became a thing. I have always enjoyed solving problems with my hands. I also enjoy writing.

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  • Build Your Own DIY 3D-Printed Soldering Fume Extractor

    Nice Instructible! Nice project for a 3D printer. Only wish I had one -- however, the box can be made of almost anything, including balsa wood which I used to work with a lot back in my model airplane days. Despite the naysayers in the comments list, there is value in removing the smoke as we solder. It's less irritating if the smoke goes into the fan and filter and not into your eyes and nose. People can debate all they want whether the pollutants are actually removed from the air. What matters for me is having a comfortable and safe work environment. For hobbyists it is often not practical or convenient to pipe the fumes outside or even open a window on a cold or hot day with HVAC systems running so this is a good compromise. BTW, flux is a plant-based product. I believe most of …

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    Nice Instructible! Nice project for a 3D printer. Only wish I had one -- however, the box can be made of almost anything, including balsa wood which I used to work with a lot back in my model airplane days. Despite the naysayers in the comments list, there is value in removing the smoke as we solder. It's less irritating if the smoke goes into the fan and filter and not into your eyes and nose. People can debate all they want whether the pollutants are actually removed from the air. What matters for me is having a comfortable and safe work environment. For hobbyists it is often not practical or convenient to pipe the fumes outside or even open a window on a cold or hot day with HVAC systems running so this is a good compromise. BTW, flux is a plant-based product. I believe most of the pollutants are in the flux carrier and not the flux itself. However, as it burns the combustibles in the flux could be mildly toxic. Also, the tin and lead in the solder don't vaporize under soldering temperatures so they are not present in the smoke.

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  • kmpres commented on ChristineNZ's instructable Piano Metronome
    Piano Metronome

    Very fine 'ible! In about half a year my old piano will finally arrive from my parents house in New York where its been since I bought it in 1978. I'm now retired and living in Japan. other than keeping it in tune during my periodic visits home I've not played the thing in 40 years. Will have to find a teacher to try to get my skills back, but I'm very much looking forward to our reunion! I have an old mechanical metronome in the classic triangular shape that's in good condition. I think I will build your circuit but put it in a triangular shaped base that the old metronome can fit onto. That way I can use either one depending on the song, or my mood, or whatever. Thanks for the idea!

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  • Soldering Microscope From SLR Zoom Lens and TV Wall Mount

    Fantastic! I've been wrestling with this problem for years after discovering that my eyes can no longer focus on tiny SMD components. Tried numerous cheap Chinese solutions but they were less than useful. Though I have an old laptop from which I can liberate its webcam, I also have a perfectly good but old 10 Megapixel DSLR that's just collecting dust. Like you, I want to use what I have and not buy any new parts, if possible. Just have to figure out how to output the image to a USB port. Can this be done easily, do you know?

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  • Automated Overhead Camera Assistant for Instructional Videos

    Awesome! I need something like this to make videos for my electronics bench. Needs to be easily controlled with one hand on a joystick and maybe two pushbutton switches for in and out zoom functions. Can that be accomodated with this design?

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  • How to Rebuild a BionX E-Bike Lithium-Ion Battery Pack

    You'll need to remove the cover and locate where the AC and DC ground points are on the circuit board inside. They are usually at the screw mounts. The AC ground will be connected to the power cord ground, the DC ground will be connected to the DC output on the edge connector. In a normal server supply both are tied together, if not on the board itself then through the case. They won't be marked as such, you'll have to buzz out all the screw mounts to see which ones go where. Once you've located the studs going to DC ground you'll need to insulate them from the board so the AC and DC grounds are no longer electrically tied together. My supply had two screw points tied to DC so I replaced the metal screws with non-conducting screws I made out of small bits of perfboard and pieces of …

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    You'll need to remove the cover and locate where the AC and DC ground points are on the circuit board inside. They are usually at the screw mounts. The AC ground will be connected to the power cord ground, the DC ground will be connected to the DC output on the edge connector. In a normal server supply both are tied together, if not on the board itself then through the case. They won't be marked as such, you'll have to buzz out all the screw mounts to see which ones go where. Once you've located the studs going to DC ground you'll need to insulate them from the board so the AC and DC grounds are no longer electrically tied together. My supply had two screw points tied to DC so I replaced the metal screws with non-conducting screws I made out of small bits of perfboard and pieces of a bamboo yakitori stick (believe it or not). I'd have used nylon bolts if I had them the right size. I also placed slightly oversized washers cut from a scrap piece of plastic underneath the board to keep the mounting studs from contacting the board's underside. When you're done you can test the isolation by checking continuity between the case and the DC ground point on the output edge connector. You should see an open circuit. Continuity between the case and the AC ground pin on your power cord should remain at zero ohms, however. Do this to only ONE of your two supplies. That way the AC ground is carried over to both supplies and the DC ground of the modified supply is tied to the positive output of your unmodified supply. The positive output of your modified supply then becomes your +24V output. When done properly, your cases should have zero volts between them. If your voltmeter says otherwise then your DC ground is not fully isolated. Touching the cases together while in this condition will yield sparks! Also, your house outlet MUST be properly grounded or your supplies will have no ground reference. Check it with a cheap AC socket tester beforehand to be sure.

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  • How to Rebuild a BionX E-Bike Lithium-Ion Battery Pack

    I use two 12V, 75A HP power supplies wired in series to give me 24 volts DC. These are not inverters. They are high quality SMPS DC power supplies used in computer servers. I don't need anywhere near that much power so they run pretty cool. The trick is to isolate the DC ground of one supply so it "floats" over the other. Leave the AC grounds (coming from the grounded power cords) as is. When wired in series the DC positive of the unmodified supply then becomes the DC ground of the floating supply. You should also adjust their outputs so they are as close to outputting the same voltage as possible, otherwise one will tend to do more work than the other. Your Graupner Duo 80 Plus balance charger should work fine as long as you feed it with clean DC, either from a high qual…

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    I use two 12V, 75A HP power supplies wired in series to give me 24 volts DC. These are not inverters. They are high quality SMPS DC power supplies used in computer servers. I don't need anywhere near that much power so they run pretty cool. The trick is to isolate the DC ground of one supply so it "floats" over the other. Leave the AC grounds (coming from the grounded power cords) as is. When wired in series the DC positive of the unmodified supply then becomes the DC ground of the floating supply. You should also adjust their outputs so they are as close to outputting the same voltage as possible, otherwise one will tend to do more work than the other. Your Graupner Duo 80 Plus balance charger should work fine as long as you feed it with clean DC, either from a high quality DC power supply like mine or a pair of car batteries wired in series. One 12V supply or one battery will probably work as well as long as you keep the charging current to a level that won't sag the input voltage to your charger lower than the charger's safe minimum limit.Also, while I think it is possible to wire the two chargers in your device in series, I have never done this with my iCharger 4010 Duo so have no experience with the setup. Get it wrong and you can make one beautiful short-lived fireworks display. It would be safer for you to simply divide your pack into two halves with an XT60 connector or something and charge one half of the pack on one charger and the other half on the other charger. Just be sure to separate both the plus and ground sides between the two halves so they become two separate battery packs. That way you'll avoid creating any ground loops between them.

    Your Smart Connect board may sense an abnormally low charge state and chirp at you while you're charging the half that's still connected to it. That should stop after you connect the two halves back together. However, it's a good idea to disconnect the board completely with another XT60 connector and use that connector to attach the battery to your charger. That way the Smart Connect board is completely out of the picture. Also, it may not be necessary, but I always remove the battery from its cradle during the charge so the rest of the system can't be damaged by the charge process. Just be sure to make a separate sense cable for each battery half so your chargers sense the proper cell packs in the right order when charging.

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  • Build a Left-handed Bass / Guitar From a Right-handed Kit

    Very nicely done! I wish I'd known about guitar kits 20 years ago when my fingers were still nimble. Age and hand cramps now make playing a guitar difficult for me, but your right-to-left hand conversion gives me an idea. Would it be possible, do you think, to redesign the fretboard so it could be played without bending the wrist at such an awkward angle? That might give dexterity-challenged people like me a second chance to play a guitar well into our old age.

    I was considering a ukulele or hammer dulcimer as an inexpensive way to get started playing lap instruments. I shall have to study it some more. Thank you for the suggestion.

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  • How to Rebuild a BionX E-Bike Lithium-Ion Battery Pack

    You can use any type of hot glue, but I'd suggest a low temperature type if you can find one as it will not heat up the battery cans as much as the others. The heat can cause the heat-shrink coverings on the cans to distort if you linger too long on the cells. The Kapton tape will not be affected as it can stand temperatures up to 500 deg F.

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  • Photo Engraving With Vector Lines

    Thank you. Will check out polarr and photopea. PSE10 lacks simple drawing tools and is tricky to master. Maybe the others won't have such a high learning curve.

    Thank you. Fiverr will be a nice option if my own attempts don't work out to my satisfaction. Could not find alina_zeb in the search bar, however. Do you have a link or path for her page?

    Thanks. I haven't tried Inkscape yet but planned to for other projects. Didn't know it could smooth out pixelation.

    Thanks. Will check it out.

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  • Photo Engraving With Vector Lines

    I'm a total noob when it comes to printing on anything except paper. I have a project in the works right now that I could use some advice on. It is a simple line drawing of an antique radio schematic that I want to print or engrave onto plywood. The original drawing was a B&W scan into jpg at 96 dpi that I pulled off the internet. I've spent the last week upconverting it to 300 dpi and cleaning up the lines using an old copy of Photoshop Elements 10. Very tiring work, and it looks a lot better now, but it is still very pixelated. My original plan was to use the old toner transfer method but maybe photo engraving would be better? If so, then I have no idea how to proceed. I do not own an engraver so I will have to hire a local DIY shop to do the printing. I get only one shot at…

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    I'm a total noob when it comes to printing on anything except paper. I have a project in the works right now that I could use some advice on. It is a simple line drawing of an antique radio schematic that I want to print or engrave onto plywood. The original drawing was a B&W scan into jpg at 96 dpi that I pulled off the internet. I've spent the last week upconverting it to 300 dpi and cleaning up the lines using an old copy of Photoshop Elements 10. Very tiring work, and it looks a lot better now, but it is still very pixelated. My original plan was to use the old toner transfer method but maybe photo engraving would be better? If so, then I have no idea how to proceed. I do not own an engraver so I will have to hire a local DIY shop to do the printing. I get only one shot at this so it needs to be done right the first time around with no time or money wasted on experimentation.Questions: . Should I convert the file to some format other than jgp, and if so, what format? . Will converting the file remove the blocky pixelation I see now and smooth out the lines? . What final format is required by the engraver/printer?Thanks for helping me answer these questions!

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  • How to Rebuild a BionX E-Bike Lithium-Ion Battery Pack

    Hello Inzemoon. First, for a bit of basics, speed controllers for two-wire (brushed) motors are not compatible with those for three-wire (brushless) motors due to the way their switching electronics work. BionX motors are, however, BLDC motors and yet power is fed to them via only two wires, as your photo shows. How is that possible? Thatt's because the BLDC power electronics are all inside the motor housing. The two wire connector only feeds the battery + and - to the motor. The system's command and control circuitry are inside the battery pack except for the handlebar switches which are deliberately made low-voltage for safety reasons and ease of wiring. Regarding your battery hacks, I have to caution you that this is not a project for "frequent uncautiously handlings of the…

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    Hello Inzemoon. First, for a bit of basics, speed controllers for two-wire (brushed) motors are not compatible with those for three-wire (brushless) motors due to the way their switching electronics work. BionX motors are, however, BLDC motors and yet power is fed to them via only two wires, as your photo shows. How is that possible? Thatt's because the BLDC power electronics are all inside the motor housing. The two wire connector only feeds the battery + and - to the motor. The system's command and control circuitry are inside the battery pack except for the handlebar switches which are deliberately made low-voltage for safety reasons and ease of wiring. Regarding your battery hacks, I have to caution you that this is not a project for "frequent uncautiously handlings of the electronic board ..." as you put it. Those batteries can cause great damage if they are accidentally shorted and can even burn houses down if left unattended while charging with makeshift BMSs or other homemade circuitry. That is why I chose to go with a true balance charger in my instructable. Other than replacing the cells, the only mods I made to my battery was to add a sense wire to each cell group so the balance charger could do its work properly. And even though I was very careful, just adding those wires turned out to be a bit dicey at times. Any changes you make to your system and/or wiring you do so at your own risk. Please be careful.

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  • How to Rebuild a BionX E-Bike Lithium-Ion Battery Pack

    I don't have a schematic so I can't give you an accurate answer as to where the throttle input is on the Smart Connect 5.2 board. You'll have to trace the wires and do a bit of reverse engineering to make that determination. I will say that it is quite possible the Smart Connect 5.2 board will work with a 48 V battery but, like you, I declined to test it at that level and risk destroying the only board I had so I remade my 36 V battery pack instead. Since you tested your bike at 46 V I would say that the entire system is capable of working with a fully charged 48 V pack. It would make sense for BionX to make one board work with both packs as it reduces their production costs, but whether they did so in the Smart Connect 5.2 Board I simply don't know. I suggest that as you ride your bi…

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    I don't have a schematic so I can't give you an accurate answer as to where the throttle input is on the Smart Connect 5.2 board. You'll have to trace the wires and do a bit of reverse engineering to make that determination. I will say that it is quite possible the Smart Connect 5.2 board will work with a 48 V battery but, like you, I declined to test it at that level and risk destroying the only board I had so I remade my 36 V battery pack instead. Since you tested your bike at 46 V I would say that the entire system is capable of working with a fully charged 48 V pack. It would make sense for BionX to make one board work with both packs as it reduces their production costs, but whether they did so in the Smart Connect 5.2 Board I simply don't know. I suggest that as you ride your bike you check the heat buildup in the battery pack and the motor be sure that both are working comfortably. The battery is protected by heat sensors but the board only has a fuse protecting it. I don't know about the motor, but I suspect it has a heat sensor of its own so it can throttle back when an extended climb up a long hill makes it overheat. There's much you can learn from your tests so I invite you to report back here and fill us in on your findings.Also, you mentioned that you plan to use a buck converter to charge your battery. I strongly suggest that you use a balance charger instead, as that will greatly extend the life of your battery pack. All this is described in my instructable for reference. A BMS will also work but there may not be enough room inside the BionX cavity to fit one. Good luck if you choose to go that route.

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  • Getting Started With Ham Radio

    Congrats, Becky! I got my Tech and General licenses the same day in Nassau County in 2017. I grew up in the Big Apple but now live in Japan. Hope to have a base station set up in a few months. Starting up a Ham Radio Station in a foreign country is a whole different kind of challenge but not impossible once you learn the local rules and procedures. My goal is to DX to New York on 100 watts like my great-grandfather did before I was born. He could reach Europe and Australia from his house in Queens back in the 1920s! Enjoy the hobby and maybe we'll enjoy a QSO together sometime. 73 KD2ORG

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  • How to Build an FPV Drone (under $150)!

    Nice 'ible, I will download and try it when I get a break from my other hobbies, of which I have a few too many at the moment. I was an early adopter of FPV but in traditional model airplanes before drones became popular. I had some success at blazing my own trail but a bit too much life intervention forced me to give it up in favor of more earth-bound pursuits. I still have, however, a 1/4 scale J3 Cub and a hot-liner sailplane, both electrics, that flew with onboard cameras and video transmitters, and the Cub even had an early GPS receiver and a rudimentary auto-pilot, but that was 20 years ago and the technology was still in its infancy. It was a challenge then just to keep myself from re-kitting my planes whenever I came in for a landing. Nowadays it's almost too easy as most of t…

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    Nice 'ible, I will download and try it when I get a break from my other hobbies, of which I have a few too many at the moment. I was an early adopter of FPV but in traditional model airplanes before drones became popular. I had some success at blazing my own trail but a bit too much life intervention forced me to give it up in favor of more earth-bound pursuits. I still have, however, a 1/4 scale J3 Cub and a hot-liner sailplane, both electrics, that flew with onboard cameras and video transmitters, and the Cub even had an early GPS receiver and a rudimentary auto-pilot, but that was 20 years ago and the technology was still in its infancy. It was a challenge then just to keep myself from re-kitting my planes whenever I came in for a landing. Nowadays it's almost too easy as most of the flight controls have been taken over by computer chips, but I'm sure the video quality is better than it was when I was doing it so that might get me back into it. To that end I would suggest that you add a goggle-view video of one of your flights so we can all "see" what it is really like to "fly" a drone from the cockpit.

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  • kmpres commented on JGJMatt's instructable Plywood DML Speakers
    Plywood DML Speakers

    Very impressive! I think I saw the same Tech Ingredients YT videos you used as inspiration -- one of my favorite sites for sure. Two questions, if I may: The curved cutout on the bottom of your plywood sheets - is that to help the panels "move" while the silicone adhesive keeps them fixed to the stand or is it just a design element? Could a screw or two surrounded by soft rubber grommets replace the silicone? That would allow disassembly without having to cut through a line of silicone each time.

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  • A Modern Bandsaw Reindeer

    I made one of these 35 years ago and sent it to my girlfriend in Japan. Now my girlfriend's my wife. We've been very happy together.

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  • Magnet Powered Submarine

    Apparently, from the discussions above, more voltage will yield more thrust, but also more bubbles which will reduce thrust. The voltage level just before when bubbles appear seems to be the sweet spot. In a real sub bubbles would give away a sub's position to the enemy, both visually and aurally making stealth impossible, so a careful balance would need to be maintained, assuming of course this tech ever becomes practical for a real sub.

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  • DIY Bench Grinder to Belt Sander Conversion With Templates

    I use the belt sander to sharpen lathe and woodworking chisels. The problem with downward travel is that the belt is traveling towards the workpiece's sharpening edge often catching it and shoving it into the table. That can ruin a fine chisel blade and/or send it flying into your hands, feet or elsewhere. There is also no easy way to hold the chisel at the proper angle. With upward travel the table is angled downward so the blade points up making the belt travel away from the chisel edge, not towards it. It's important to wear a face-shield anyway and stand slightly to one side to keep sparks from flying into your face, but in my mind that has to be safer than downward travel. When I need the belt sander to sand wooden or metal parts I will use it in the "normal" fashion s…

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    I use the belt sander to sharpen lathe and woodworking chisels. The problem with downward travel is that the belt is traveling towards the workpiece's sharpening edge often catching it and shoving it into the table. That can ruin a fine chisel blade and/or send it flying into your hands, feet or elsewhere. There is also no easy way to hold the chisel at the proper angle. With upward travel the table is angled downward so the blade points up making the belt travel away from the chisel edge, not towards it. It's important to wear a face-shield anyway and stand slightly to one side to keep sparks from flying into your face, but in my mind that has to be safer than downward travel. When I need the belt sander to sand wooden or metal parts I will use it in the "normal" fashion so the belt travels downward.

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  • DIY Bench Grinder to Belt Sander Conversion With Templates

    Nice instructible! Very sturdy looking tool that should provide years of good use. I want to do the same as I need a belt sander to help me sharpen chisels and the like. I bought one from Harbor Fright some years ago but, not surprisingly, it turned out to be junk. I need to solve these problems first: 1. How to make the band move upwards rather than downwards;2. How to reduce the speed of the motor; 3. How to make the parts without requiring a welder and other exotic tools.I don't have the budget, nor space for the added tools (welder, angle-grinder, bandsaw, etc.) that I'd need to make your metal one. I figure the first problem can be handled by moving the grinding platform to the rear - essentially assembling the parts in mirror image. The second problem will require a Variab…

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    Nice instructible! Very sturdy looking tool that should provide years of good use. I want to do the same as I need a belt sander to help me sharpen chisels and the like. I bought one from Harbor Fright some years ago but, not surprisingly, it turned out to be junk. I need to solve these problems first: 1. How to make the band move upwards rather than downwards;2. How to reduce the speed of the motor; 3. How to make the parts without requiring a welder and other exotic tools.I don't have the budget, nor space for the added tools (welder, angle-grinder, bandsaw, etc.) that I'd need to make your metal one. I figure the first problem can be handled by moving the grinding platform to the rear - essentially assembling the parts in mirror image. The second problem will require a Variable Frequency Drive which can get expensive. The last problem will require the most thought, but I thank you for the inspiration.

    VFDs work with induction motors which is the type used here. They apply full voltage to the motor as they vary the frequency, which in turn, varies the speed. Torque is maintained more evenly than using SCR/Triac type speed controllers, like the Harbor Freight device mentioned above, which achieve variable speed by chopping the 60 Hz line frequency every cycle or half cycle depending on whether an SCR or Triac is used. This reduces the power you can get from each cycle which reduces speed but also the torque. I bought the Harbor Freight device some years ago but it didn't work at all. Very poor quality control so I don't recommend it. I ended up designing my own circuit and fitting it inside the HF box. Works for incandescent lights and corded electric drills but not much of anythi…

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    VFDs work with induction motors which is the type used here. They apply full voltage to the motor as they vary the frequency, which in turn, varies the speed. Torque is maintained more evenly than using SCR/Triac type speed controllers, like the Harbor Freight device mentioned above, which achieve variable speed by chopping the 60 Hz line frequency every cycle or half cycle depending on whether an SCR or Triac is used. This reduces the power you can get from each cycle which reduces speed but also the torque. I bought the Harbor Freight device some years ago but it didn't work at all. Very poor quality control so I don't recommend it. I ended up designing my own circuit and fitting it inside the HF box. Works for incandescent lights and corded electric drills but not much of anything else. Thanks for the link. Mr. Fielding is very knowledgeable and gives good, clear overviews of motor and speed controller types in his videos.

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  • OPEN DESKTOP ENCLOSURE    for Raspberry Pi or Similar SBC

    Fantastic project, and a great way to provide a good education to some of the poorer regions of our planet! I like that this enclosure completely avoids fans which are often the first things to go in dusty environments. I'd put a small heatsink on the CPU chip anyway. Could keep it from overheating in classrooms that are not well air-conditioned. Some air ventilation holes in the tilt cover would help as well.

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  • kmpres commented on douwe1230's instructable UV Curing Station
    UV Curing Station

    An excellent explanation. I had thought that the motor would load the circuit down some but was thinking in terms of current drawn from the power supply. The equivalent resistance concept makes it so much clearer, thank you.

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  • kmpres commented on douwe1230's instructable UV Curing Station
    UV Curing Station

    Nicely done project! I like the construction using CNC cut sides - makes for a very professional looking enclosure. A few comments, if I may: First, you say that a 1K to 10K voltage divider will produce 6V if 12V is fed to the ends? By my math, that will produce 10.9V. The formula is Vout = (Vsource x R2) divided by (R1 + R2). Numerous online calculators will confirm this. Also, I agree with other commenters about the safety issues with UV light so perhaps adding springs to the door hinges will keep the UV light in the box except during short inspections. Also, a micro-switch added to the door to turn the UV LEDs off whenever the door is opened will prevent any exposure.The greater safety hazard, in my opinion, is the use of UV curing resin to begin with. As anyone who owns a UV …

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    Nicely done project! I like the construction using CNC cut sides - makes for a very professional looking enclosure. A few comments, if I may: First, you say that a 1K to 10K voltage divider will produce 6V if 12V is fed to the ends? By my math, that will produce 10.9V. The formula is Vout = (Vsource x R2) divided by (R1 + R2). Numerous online calculators will confirm this. Also, I agree with other commenters about the safety issues with UV light so perhaps adding springs to the door hinges will keep the UV light in the box except during short inspections. Also, a micro-switch added to the door to turn the UV LEDs off whenever the door is opened will prevent any exposure.The greater safety hazard, in my opinion, is the use of UV curing resin to begin with. As anyone who owns a UV printer should know, but many who don't own one may not know, you don't want to get the resin on your skin. It is difficult to remove, and when sunlight hits it, it cures in your pores - definitely not a good thing. Care should be taken at all times when handling the stuff.

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  • kmpres commented on RobBest's instructable Cat Repellent
    Cat Repellent

    Nice project! I wonder, does it work on dogs, too? I heard that some anti-bark devices work on a similar principle, but one has to fire the device every time a dog barks or he'll not associate the sound with the bark. I should warn, though, that too loud a sound, even if it is ultrasonic, can hurt your pet's ears just like loud noises can hurt our ears, so beware!

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  • Giant Luxo L-1, "Luxo Senior"

    Very nicely done! I have modified similar but much smaller lamps for use on my electronics bench. Good use of concrete in yours. I had considered a similar solution for my lamps but opted instead to clamp the existing base to the table top using a $5 clamp designed for lamps with a stud in the base joint to allow the arm to swivel. I also modified the base joint to allow the arm to come forward and extend to almost flat - a big improvement as the originals were very restricted in this movement. One thing you might try on your lamp is to shorten the length of your springs an inch or two to increase their pull strength. That might help you tune them so they hold up the exact weight of your lamp in any position without it rising or falling.

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  • How to Rebuild a BionX E-Bike Lithium-Ion Battery Pack

    Whoa, slow down. I'm old-school. I can't read-stream-of-consciousness messages when they don't follow standard rules of grammar, spelling or proper sentence structure. I gather you're trying to charge a 12S battery with a 10S charger. It won't work because you need slightly more voltage than what the battery's maximum charge voltage will be to reach full capacity. A 12S5P battery (12 clusters in series, 5 cells per cluster in parallel) has a nominal voltage of 44.4 volts (3.7 volts per cell). When fully charged it will reach 50.4 volts (4.2 volts per cell). Your charger has to be able to go past 50.4 volts. If it can't, you won't ever get a full charge into your pack. You have two choices: Buy a good balance charger that can charge 12S batteries, or buy a higher voltage standard …

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    Whoa, slow down. I'm old-school. I can't read-stream-of-consciousness messages when they don't follow standard rules of grammar, spelling or proper sentence structure. I gather you're trying to charge a 12S battery with a 10S charger. It won't work because you need slightly more voltage than what the battery's maximum charge voltage will be to reach full capacity. A 12S5P battery (12 clusters in series, 5 cells per cluster in parallel) has a nominal voltage of 44.4 volts (3.7 volts per cell). When fully charged it will reach 50.4 volts (4.2 volts per cell). Your charger has to be able to go past 50.4 volts. If it can't, you won't ever get a full charge into your pack. You have two choices: Buy a good balance charger that can charge 12S batteries, or buy a higher voltage standard charger with a BMS that has taps for 12 cells. A third option is to charge your pack in two halves of 6 clusters each but you'll still need a BMS for each half. Make sure that when you rejoin both halves back together, they are at exactly the same charge level or the stronger one will attempt to charge the weaker one. The inrush of current can damage them both if you're not careful. Either way you're going to have to spend some money. A good charger will make your battery last a long time. A bad one will destroy it in no time flat.

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  • kmpres commented on Woodbrew's instructable Homemade Drum Sander
    Homemade Drum Sander

    Well done! Nicely thought out and executed. About the only thing I'd have done differently is move the bearing holders 90 degrees so the oil cup is on top. That should keep the oil from leaking out and running down those nice melamine sides you've made.

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  • Giant Functioning Emergency Stop Button

    Most are rated at around 0.1A to 3A. Those salvaged from printers and other home mechanisms, as those appear to be, are usually in the 0.3A to 0.6A range. You can buy higher rated switches but they are hard to find and cost more.

    I'm sure that's true, but I was specifically referring to the switches seen in the instructable. The author refers to them as limit switches and limit switches should only pass signals, not power. Also, the link he provides indicates that they are good for 5 amps, but I usually down-rate anything I buy on eBay and Amazon as one never knows if the Chinese manufacturer is being honest with his ratings.

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  • Giant Functioning Emergency Stop Button

    Nice! I'm glad you said in your intro that this is a fun project and that it should not be used as a real emergency button. Those limit switches are designed to pass signal currents only, that is, not more than a few amps at low voltages. Any power circuit, even a small one, will fry them. Some on-off LEDs for demonstration purposes, though, would be ideal.

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  • kmpres commented on gabbapeople 's instructable Arduino Barrel Piano
    Arduino Barrel Piano

    Very nicely done! I've been mentally designing such a system off-and-on since I bought my first piano in the 1970s. Never built it because I couldn't figure out how to add true piano-forte capability. How do you vary the loudness of each note so your device plays loud and soft notes like a human piano player does?

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  • How to Rebuild a BionX E-Bike Lithium-Ion Battery Pack

    The only BionX battery type I am familiar with is the one in my instructable. If yours is different then the instructable may not be relevant to you. However, we can make a few assumptions as some things will be the same for all 37 volt packs. First, you say that your pack is 5P12S? If you mean 12S5P then that is a 44.4 volt pack (12 x 3.7v = 44.4v). The correct convention is S-P (Series-Parallel) so a 37 volt pack should be 10S4P or 10S6P. Please verify that before you go any further. Then you'll need to test each cell group in your pack to verify that they are charging properly. When fully charged they should all read very close to 4.1 volts with very little variation between them. If any are less than that after a full charge then your pack is not balanced and it will only las…

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    The only BionX battery type I am familiar with is the one in my instructable. If yours is different then the instructable may not be relevant to you. However, we can make a few assumptions as some things will be the same for all 37 volt packs. First, you say that your pack is 5P12S? If you mean 12S5P then that is a 44.4 volt pack (12 x 3.7v = 44.4v). The correct convention is S-P (Series-Parallel) so a 37 volt pack should be 10S4P or 10S6P. Please verify that before you go any further. Then you'll need to test each cell group in your pack to verify that they are charging properly. When fully charged they should all read very close to 4.1 volts with very little variation between them. If any are less than that after a full charge then your pack is not balanced and it will only last as long as the weakest cell group lasts. When that cell group loses its charge the voltage of the whole pack will suddenly drop and the monitoring circuitry will cut the supply to the motor in order to protect the pack from over discharge. Also, all batteries should be rated for the same capacity. Do not mix battery capacities or old and new batteries of the same capacity as they will not charge or discharge evenly. I recommend you balance charge your pack rather than use the stock BionX charger as that will guarantee that each cell group will charge to its full capacity. The instructable goes into great detail on how to do that.

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  • Micro Sandpaper Detailing Tool

    Nice idea! I could use this in radio restoration projects. Have you tried dipping the hot-glued Q-tips into pots of polishing compound instead of onto disks of sandpaper?

    Powdered grit is available online in many sizes. It's often called lapping compound, check McMaster-Carr for examples. You can even buy diamond dust online, but why bother with the mess when some excellent fine and super fine wet/dry sandpapers are available very inexpensively. The stick part is easy - just use a popsicle stick or tongue depressor. A single piece of sandpaper can make maybe 50 sanding sticks. Coarse and fine sides of the stick can also be made with two or more different grits.

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  • How to Rebuild a BionX E-Bike Lithium-Ion Battery Pack

    Absolutely! Any Lithium-Ion 18650 cell will work but the Panasonic NCR18650B cell's high capacity and a high discharge capability make it particularly well suited for use in electric vehicles, including e-bikes and high performance cars like the Tesla Model S.

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  • Magnetic Loop Controller for 4 Antennas

    Very interesting project! I have been researching magnetic loops for some time now while trying to set up a ham radio station in space that is much too small for a traditional antenna. I have a few questions, if I may. First, is your loop a transmitting antenna, and if so, how many watts can you transmit, or do you use it just for receiving signals? Also, your video suggests that you can tune a loop from 7 mHz to 30 mHz. That's quite an amazing feat for most loops as they usually can't transmit on more than two bands without running into severe SWR problems outside their resonant ranges. How did you achieve such a wide tunable range for your loop, and how low can you get your SWRs for the various HF bands? Finally, can you show us a video of your loop antenna so we can see the capa…

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    Very interesting project! I have been researching magnetic loops for some time now while trying to set up a ham radio station in space that is much too small for a traditional antenna. I have a few questions, if I may. First, is your loop a transmitting antenna, and if so, how many watts can you transmit, or do you use it just for receiving signals? Also, your video suggests that you can tune a loop from 7 mHz to 30 mHz. That's quite an amazing feat for most loops as they usually can't transmit on more than two bands without running into severe SWR problems outside their resonant ranges. How did you achieve such a wide tunable range for your loop, and how low can you get your SWRs for the various HF bands? Finally, can you show us a video of your loop antenna so we can see the capacitor in action as you change frequencies? Thanks for sharing a great instructible!

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  • Fixing an Expensive Photo Lens ( Canon 85mm F1.2 L II )

    Good tip on the ultrasonic cleaner. I recently acquired one to use to clean radio parts. It's also been a few years since I wrote my last instructible. You might check them out if you're interested. Thanks for the quick response.

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  • Fixing an Expensive Photo Lens ( Canon 85mm F1.2 L II )

    Excellent instructible! It reminded me that I have a Canon AE1 Program with, if I recall correctly, a 75 to 200 mm zoom lens that has not been used in probably twenty years. I took the kit to a professional camera shop for resale evaluation and he said he could see evidence of mold growing inside the lenses. To my eyes the mold was very minor, like tiny dust specs, but he said the camera and lenses were worthless and could not be repaired. Worthless! I was so annoyed! What he probably meant was that it was not profitable to disassemble and clean them. OK, that just means that I will have to do the work. The lenses work perfectly otherwise. So that leaves the question, how can I clean the lenses without damaging their coatings? What chemical should I use? Thanks!

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  • PiNAS - the Raspberry Pi NAS

    Wow. Very impressive piece of work, this Alt-F. Thank you for the info. I now must decide whether my old 321 is worth learning another OS (Linux) just to get it online or stick with the old driver which, though flawed, is as turn-key as it gets. I learned six programming languages and three OSs in my day but Linux came too late for me to master its confusing syntax. Can you walk me through the process of loading Alt-F so I don't brick my NAS or lose my data? Thanks!

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  • PiNAS - the Raspberry Pi NAS

    Very interesting project! I have a ten year old D'link DNS-321 NAS set up for RAID 1 that works well as long as I use an out-of-date Windows driver with a known security flaw. Microsoft fixed the security flaw in one of their Windows updates but it is not compatible with this old NAS. To make matters worse, D'link no longer supports the DNS-321 so I'm now forced to use mine as little as possible and only when I'm off-line. If I build this Pi-NAS, will it be able to access my old D'link drives without my having to reformat them? Obviously I'd prefer to keep my old data in them, if possible. Thanks!

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  • Dementia Friendly Media Player

    Excellent. Before my father passed away we got him a Google Alexa device and tried to teach him how to use it. He couldn't. The modern concept of voice commands was so alien to him that I think he simply couldn't understand how a puck-like device could do all the things it claims to do. However, a Japanese company has invented a cute human-like robot for seniors to talk to and they seem to find that comforting. The simplicity and homey feel of an old-fashioned radio is a great idea. I hope someone thinks of it for me when I get old and feeble.

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  • kmpres commented on tomatoskins's instructable Compact Dust Collector
    Compact Dust Collector

    Very nice! I have two problems: 1. A very small space (even smaller than yours), and 2. I can't stand the noise that el-cheapo shop vacs make. MUCH more irritating than all of my power tools combined. A sound-deadening enclosure is not practical due to the space it requires and the difficulty in providing adequate ventilation through the foam padding while still attenuating the whine of the motor. I have several sets of ear muffs, and they work, but no, I'm not going to put them on just to turn on my shop vac. Call me stubborn, but I think shop vacs should be designed to not make the operator go deaf to begin with. I'm sure are there effective ways around these two problems but I haven't found any I like yet. Any ideas?

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  • Quarter Iso-grid Cardboard Longboard

    Exactly, which is why I suggested the Saran Wrap. It allows you to glue up only the center structure and leave the acrylic layers attached only by the screws. You could also assemble the pieces fully cured but not glued together as you did with just the cardboard taking advantage of the added strength but retaining some of the flexibility you had before. You may even be able to program the degree of flex by gluing some of the pieces together but not all of them, or by tightening the screws a certain way or changing their number in certain areas. Your Fusion 360 S/W looks like a great modeling tool for these kinds of studies. However, these are just ideas to think about. You are to be congratulated for coming up with the original design concept. I hope you'll continue development of…

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    Exactly, which is why I suggested the Saran Wrap. It allows you to glue up only the center structure and leave the acrylic layers attached only by the screws. You could also assemble the pieces fully cured but not glued together as you did with just the cardboard taking advantage of the added strength but retaining some of the flexibility you had before. You may even be able to program the degree of flex by gluing some of the pieces together but not all of them, or by tightening the screws a certain way or changing their number in certain areas. Your Fusion 360 S/W looks like a great modeling tool for these kinds of studies. However, these are just ideas to think about. You are to be congratulated for coming up with the original design concept. I hope you'll continue development of your design and share them with us in future instructables.

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  • Quarter Iso-grid Cardboard Longboard

    Very imaginative design! I love the look of the board. A few words of advice: Glue-ups are tedious things but often necessary. That's what makes hollow doors so rigid and stable. Do away with the glue and you lose rigidity and let time and humidity slowly rot the structure. You'll probably find some flexing in the truck mounts as well which could impact the ride and style of stunts you perform. You could dip the pieces in thin epoxy, then assemble them in place over a Saran Wrap covered acrylic top board. When the structure is fully cured remove the Saran Wrap, trim off the flash with a sharp knife, and reassemble the top and bottom plates. You'll get the same look as before but with a lot more added rigidity as well as protection from humidity, bugs, mold etc.

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  • DIY Sandblasting Cabinet and Etching Glass

    Nice project. I presume the $50 cost does not include the cost of the air compressor. Also, you should keep the box out of the sun or cover it up when not in use. The reason the plastic becomes brittle is because it breaks down in the presence of UV light. It only takes a year or two for this to happen. White translucent plastic is especially prone to this - don't ask me how I know. One final tip that others have mentioned: If you put in a removable Plexiglas panel in the top you'll both see better and be able to repair or replace it when it becomes cloudy.

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  • Etch a Circuit Board With Kitchen Supplies

    Interesting discussion. It'd been some four decades since I took college chemistry and now I know why I never made it my career -- electricity is complicated enough! As for keeping track of all the chemicals in a home-brew etchant solution, old-fashioned ferric chloride starts to look good in comparison. Very simple to use and you can neutralize it with sodium carbonate (washing soda) to prepare it for disposal. Some kits also come with an agent that converts it to a solid which can then be thrown away in the trash.

    Not a good idea. All laser printers pass the toner-deposited pages through a hot roller called a fuser that bonds the toner to the paper. It can get as hot as 400 deg F. The wax would probably melt all over the fuser roller ruining any prints that followed, assuming the wax paper doesn't jam in the machine as it passes through. The reason why laser printers need a minute or so to boot up from a cold off state is to give the fuser time to reach operating temperature.

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  • kmpres commented on Natalina's instructable Build a Soundproof Wall
    Build a Soundproof Wall

    Nice instructable. I may apply some version of it in my next house if I find the noise coming in from outside is unbearable. Another tip for new house construction I heard over the internet is to make the outer walls of the house two inches thicker than what the studs and opposing drywall sheets would add up to. You then stagger the studs in a zig-zag pattern so the drywall on one side is nailed only to the even studs and the drywall on the other side is nailed only to the odd studs, then fill the space with as much insulation/sound-deadening material as you can fit. This decouples the wall surfaces and makes a kind of pleated but undivided dead-air space between them and also reduces conduction through the studs because each stud touches only one drywall surface. They cannot conduct …

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    Nice instructable. I may apply some version of it in my next house if I find the noise coming in from outside is unbearable. Another tip for new house construction I heard over the internet is to make the outer walls of the house two inches thicker than what the studs and opposing drywall sheets would add up to. You then stagger the studs in a zig-zag pattern so the drywall on one side is nailed only to the even studs and the drywall on the other side is nailed only to the odd studs, then fill the space with as much insulation/sound-deadening material as you can fit. This decouples the wall surfaces and makes a kind of pleated but undivided dead-air space between them and also reduces conduction through the studs because each stud touches only one drywall surface. They cannot conduct sound to the other side because they don't touch the other side. For the same reason it also makes a better thermal barrier for heat retention. You and your readers could now help me with a sound-deadening problem I've been wrestling with. Seems my new shop vac is loud enough to cause avalanches, earthquakes, hair loss and migraines, oh, and hearing loss as well. I need to fit it inside some kind of sound-deadening enclosure so I can use it and still preserve my hearing for a happy, sound-filled retirement. It needs to be light, movable and somewhat form-fitting. Any ideas?

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  • DIY Shishi Odoshi

    Very nicely done! I plan to make one when we move into our new home in a few months. The shishi-odoshi I have seen often have a rock placed under the bamboo spout so when it empties the heavy end strikes the rock giving a nice bamboo "thunk" sound. This is what scares off the inoshishi (wild boars) and shika (deer). No Japanese garden should be without one.

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  • I had no idea this was possible. Looking forward to the lost PLA method of metal molding using one of these.

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  • I never heard of baking a steak. Nobody does that in the country where I live possibly because few people have ovens in their homes. Also, one-inch steaks are insanely expensive and usually reserved for hotels and steak houses. The rule here is to pan-fry the 1 cm thick supermarket steaks in olive oil or char broil marinated strips on a Korean BBQ. It takes just minutes and they taste great. BTW, popular TV programs here have said that searing steaks can increase your risk of getting cancer. Maybe so, but what a way to go!

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  • I'm not sure what you mean by "full rebuild on the housing". I did not want to change the appearance of my housing so just rebuilt the pack and made only slight internal changes to the housing to make it fit. Adding balance wires was a way to improve the charge and longevity of the pack while preserving the original circuitry. If you have access to a spot welder you could, conceivably, build a closer copy of the original pack and avoid the mods to the housing I had to make, but some experimentation will be necessary and you'll probably waste some cells in the process. Or you could add balance wires to an existing pack and attempt to "revive" it with a better charger, though there's no guarantee that would be worth the effort. I did not try that because I wanted mo…

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    I'm not sure what you mean by "full rebuild on the housing". I did not want to change the appearance of my housing so just rebuilt the pack and made only slight internal changes to the housing to make it fit. Adding balance wires was a way to improve the charge and longevity of the pack while preserving the original circuitry. If you have access to a spot welder you could, conceivably, build a closer copy of the original pack and avoid the mods to the housing I had to make, but some experimentation will be necessary and you'll probably waste some cells in the process. Or you could add balance wires to an existing pack and attempt to "revive" it with a better charger, though there's no guarantee that would be worth the effort. I did not try that because I wanted more power than my old pack could deliver and replacing the cells with higher capacity ones was the only way to achieve that. Replacing all the cells was also safer than replacing just the bad ones which would have required a very dangerous disassembly process and resulted in a pack with unmatched cells in it. Also, because BionX packed their electronics inside their battery packs, replacing the whole package was an easy but expensive proposition that ultimately didn't work out well for them. Finding one in fresh condition at this point might be easier for you in Canada than it was for me in Korea but it would still be expensive.

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  • Many people, particularly those who had or have careers in technology, enjoy restoring old tube sets from the 1920s to 1960s, often called the golden age of vacuum tubes. The technology is fascinating, the parts are easy to handle and understand, and when a working set rises out of the ashes of time it is a joy to behold! My guess is that this is particularly popular these days because it reminds people of the fun they had in tuning in radio stations and playing the vinyl records of their youth. Any radio in good physical condition can be restored, you've only to look online for details on how it is done. Young people who grew up with boomboxes and Bluetooth really don't appreciate this unless they know someone who does radio restoration for a hobby. Try restoring an antique radio ra…

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    Many people, particularly those who had or have careers in technology, enjoy restoring old tube sets from the 1920s to 1960s, often called the golden age of vacuum tubes. The technology is fascinating, the parts are easy to handle and understand, and when a working set rises out of the ashes of time it is a joy to behold! My guess is that this is particularly popular these days because it reminds people of the fun they had in tuning in radio stations and playing the vinyl records of their youth. Any radio in good physical condition can be restored, you've only to look online for details on how it is done. Young people who grew up with boomboxes and Bluetooth really don't appreciate this unless they know someone who does radio restoration for a hobby. Try restoring an antique radio rather than converting it into something modern and mass produced. I guarantee you, the experience will be much more satisfying!

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  • Hello Pete,Unfortunately, I'm rather restricted myself these days. I live in Tokyo, Japan and actually rebuilt my Bionx pack in Seoul, South Korea when I lived there about three years ago. As I recall, buying quality lithium-ion cells was quite difficult and expensive from overseas. Getting them shipped from America was impossible due to shipping regulations, I couldn't get Japanese vendors to send them to me in bulk (even though Panasonic theoretically makes them in Japan) and those from China are always suspicious so I ended up buying them at high cost from Sweden. It might be easier for you to buy them in Canada but for me it was quite difficult. Also, my Bionx motor developed a flaw while I was in Seoul (the torque assist circuit would engage randomly making the bike quite danger…

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    Hello Pete,Unfortunately, I'm rather restricted myself these days. I live in Tokyo, Japan and actually rebuilt my Bionx pack in Seoul, South Korea when I lived there about three years ago. As I recall, buying quality lithium-ion cells was quite difficult and expensive from overseas. Getting them shipped from America was impossible due to shipping regulations, I couldn't get Japanese vendors to send them to me in bulk (even though Panasonic theoretically makes them in Japan) and those from China are always suspicious so I ended up buying them at high cost from Sweden. It might be easier for you to buy them in Canada but for me it was quite difficult. Also, my Bionx motor developed a flaw while I was in Seoul (the torque assist circuit would engage randomly making the bike quite dangerous to ride) so I had Bionx send me a replacement, but that didn't last long either. They kindly sent me another one but that one was speed restricted and locked. By then I was moving back to Tokyo and had no time to follow up with them. I've since learned that they have gone into receivership and don't know if they've managed to stay in business. My battery pack still works and I keep it cycled with my balance charger so my plan now is to disassemble the original motor and repair its defective torque-assist circuit. Hopefully I'll get to that after I move into a new house later this year. As for your battery, it sounds like you're suffering from the same charge problem I had. The Bionx charger cannot balance charge the pack so inevitably some cells will weaken to the point where the monitoring circuitry will refuse to allow the whole pack to charge. That's a pity because the packs cannot be easily disassembled due to the spot-welding done at the factory. A balance charger could possibly bounce the pack back to life, or at least tell you which cell cluster is bad, but you'll still have to disassemble the pack to attach the balance wires and remove any bad cells. I don't recommend this due to the danger of creating shorts. Your best bet, really, is to rebuild the pack following my instructable, but you'll need to get really good with a soldering iron first, or build a DIY spot-welder, several of which are on Instructables and elsewhere on the net. I'd do it for you if I had the time, but it is a labor-intensive project and my location would probably prevent me from sending you the finished product anyway. Canada has a large DIY community so I'm sure you can find someone local to you who can do this work for you.Good luck!Brucekmpres

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  • A most impressive build! I applaud your ability to stay focused on the more monotonous aspects and follow the project through to completion -- the end result was worth the time spent! One caution, though. I have a box full of seldom used cheap servos that have failed in one way or another, most becoming slow, inaccurate or sloppy. The weakest part seems to be the potentiometer. With 114 inexpensive servos in one device, the chances of them failing one by one as time goes on are pretty good. I hope you bought spares!

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  • Fantastic! I have aviation history in my family and have an archive of aviation photos from WW1 and the 1920s. I wrote a 500 page book on the subject (but because I don't know if it is fair to advertise in these comments so I will only respond privately to requests for information). But pursuant to those photos was a question asked by the curator of the Deutches Museum in Munich on the exact color scheme of the only Dornier Libelle II left in the world which they possess. The plane once belonged to my grandfather and we have numerous photos of him on or in it, but no one, including the museum, knows what the original color scheme was. Dornier did a beautiful job of restoring the plane but painted it grey because that was the color in the photos they used for reference. Can this AI p…

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    Fantastic! I have aviation history in my family and have an archive of aviation photos from WW1 and the 1920s. I wrote a 500 page book on the subject (but because I don't know if it is fair to advertise in these comments so I will only respond privately to requests for information). But pursuant to those photos was a question asked by the curator of the Deutches Museum in Munich on the exact color scheme of the only Dornier Libelle II left in the world which they possess. The plane once belonged to my grandfather and we have numerous photos of him on or in it, but no one, including the museum, knows what the original color scheme was. Dornier did a beautiful job of restoring the plane but painted it grey because that was the color in the photos they used for reference. Can this AI program bring back the original colors of this long lost airplane for us?

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