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RicksterInstructables

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137CommentsSouthern California, USA
After 29 years as an Electrical Engineer performing digital and analog hardware design and programming - specializing in Embedded Systems Engineering, I'm retired. That allows me to enjoy my passion for sailing (year round here in Southern California)! I still find time to dabble in DIY projects, mentor startups, design hardware (and program it) for people or just for fun. You know the mantra - if it ain't broke, take it apart and make it better.

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  • Etch a Circuit Board With Kitchen Supplies

    I used this technique quit a lit back in the day of through hole parts.i found it extremely difficult to drill the holes without breaking many, many very brittle drill bits.Suggestion:I found that putting the board (after applying toner and removing paper) in a toaster oven worked wonders.Heat or “toast” the board face up until you see the toner just begins to melt.It will gloss up a bit.(I used to know the exact temperature to set the toaster oven, but forgot long ago).It ends up looking like the “raised ink” on business cards.This extra princess step seems to significantly reduce pinholes in the toner that lead to bad traces.i think it also helps seal the toner to the board so you get less lifting and undercutting.

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  • Wacom Pen Holder Hand AKA Making a Plaster Cast of Your Hand

    I assume the alginate is fairly waterproof once set?To estimate the amount if plaster needed:Fill your mould with water to the level you want the plaster.Pour the water into a marked container of some sort (measuring cup, pitcher etc).Heck, maybe just use the water that came out to mix your plaster.

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  • I like it a lot. Very versatile tool you’ve created.Did you consider somehow mounting the saw on top?I’m thinking if you did that you might be able to use the “angle mechanism” (you can tell I’m not a woodworker, I don’t know what it’s called!).And the dust wouldn’t all go right into the saw motor vents.I’m not sure how you’d do the slot in the table, or the bearings if the saw were on top...

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  • Very nice looking job.I’m planning to build something similar and you’ve given me some ideas.A couple questions/comments if you have a moment?1) I’d strongly suggest you add a fuse. At least to the 110V input. You can get IEC sockets with a fuse holder built in, and they usually have a cute red switch (remember that the current in the 110V line won’t be 6A). Id consider a fuse between the 36V supply and the variable supply. I’d also consider a fuse in your output to the red binding post. Even if both your supplies are current limited. (Put the meter on the output side of the fuse, or best attach it right to the binding post). If you use a 10A fuse, I don’t think it will add much resistance and thus current induced droop and ripple (a smaller fuse would have higher resistance). You could u…

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    Very nice looking job.I’m planning to build something similar and you’ve given me some ideas.A couple questions/comments if you have a moment?1) I’d strongly suggest you add a fuse. At least to the 110V input. You can get IEC sockets with a fuse holder built in, and they usually have a cute red switch (remember that the current in the 110V line won’t be 6A). Id consider a fuse between the 36V supply and the variable supply. I’d also consider a fuse in your output to the red binding post. Even if both your supplies are current limited. (Put the meter on the output side of the fuse, or best attach it right to the binding post). If you use a 10A fuse, I don’t think it will add much resistance and thus current induced droop and ripple (a smaller fuse would have higher resistance). You could use bulkhead fuse holder(s) and install them on the back... with bulkhead socket holders you won’t need to disassemble everything...Why all these fuses? Even if the supplies are current limited, if a short develops - (either at your load, or inside your box due to a wiring short or failing component.), you can see from the big letters on the box 180W. That’s a lot of heat inside your box. Something will get very unhappy. Smoke will blow out the cluster of fan holes in the back. Uses slow blow fuses, rated just below the current rating of your supplies.2) you might add some kind of schematic. For instance, I wasn’t sure if the on/off switch is on the input of the 36V supply, on the output of the 36V, or the output of the buck regulator. I wasn’t sure if ground carried through from the iec socket to the black terminal post or not. Your description of wiring the panel meter was confusing. Lots of bench supplies have a floating output (black/negative is not grounded) and then they add a third green terminal that is grounded. You can tie green to black if you want your load grounded. The green terminal also makes a good spot to plug in your ESD strap.3) if it’s on the input, make sure the switch is rated for 120V. If anywhere else, make sure it can handle the current.4) if it were me, I’d put a main switch on the back for the 110V.5) if it were me, I’d add a toggle switch on the output of the regulator on the way to the red post. That way you can shutdown your load and adjust the voltage without having to pull the leads out.6) those meters are a royal pain because the current measurement is in the return path (the black lead, not the red lead).That means that any current that goes from the supply to the load on the RED wire, but somehow finds its way back to the power supply via a path other than the BLACK wire won’t register... this would be more often a problem if you decided to add a second output with a meter - say both 5V and 3.3V to a project. Most loads would have a common ground. So, you don’t know which black wire the current will go back on...If anyone knows of a source for these meters that measures current in the POSITIVE lead TO THE LOAD, please let me know!!! I want some!7) finally, I’d put some capacitors right across between the two output terminals. Make sure they are rated in excess of the maximum voltage. I might use a 100uF (or 10uF), a 1UF and a 0.1F.

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  • I LOVE it!All kinds of Halloween ideas...This might be the project that makes me buy a 3D printer.For anyone doing any kind if project with RC servos, I highly recommend a “servo tester”.They are not expensive and allow you to do all kinds of testing (like limits, binding etc.) without messing around with scripts.There are tons of manufacturers and levels of sophistication - some allow you to see/set the PWM value digitally.Here’s a link to the cheapo one I have.(I can’t believe this vendor is selling a three pack for much less than I paid for one).https://www.amazon.com/Ximimark-Digital-Consistency-Controler-Checker/dp/B07JVK7PVP(I have no affiliation with or connection to this vendor).

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  • Amazon now carry’s a line of small UPS.from the comments, they don hold much energy.but they’d keep the clock going on you VCR (what’s a VCR:)what’s a vcr without a blinking clock?i doubt the inexpensive amazon ones I reference could power a 3D printer for very long.in the comments, people have wildly different opinions of how long a pc will last on each model. Most of them have no clue. They do not know the difference between Volts, Amps, Watts and most importantly Amp Hours and Watt Hours.(they make strange, but authoritative, estimates based on the VA rating of the device. Which has no relationship to the capacity of the battery). That’s where the Amp Hours (Ah) of the battery are multiplied by the voltage of the battery (probably 3.2V or 12V) to get Watt Hours. Then you determine how…

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    Amazon now carry’s a line of small UPS.from the comments, they don hold much energy.but they’d keep the clock going on you VCR (what’s a VCR:)what’s a vcr without a blinking clock?i doubt the inexpensive amazon ones I reference could power a 3D printer for very long.in the comments, people have wildly different opinions of how long a pc will last on each model. Most of them have no clue. They do not know the difference between Volts, Amps, Watts and most importantly Amp Hours and Watt Hours.(they make strange, but authoritative, estimates based on the VA rating of the device. Which has no relationship to the capacity of the battery). That’s where the Amp Hours (Ah) of the battery are multiplied by the voltage of the battery (probably 3.2V or 12V) to get Watt Hours. Then you determine how many watts you’re drawing (amps to router times volts to router is watts to router - and voila. Watt Hours (available) divided by watts (being consumed)... drumroll... is Hours.of course the regulators are probably 80% or so efficient so you should derate for that.(if you’re confused by my math, remember that Amp Hour Ah is not Amps per hour (which would be A/h) it’s more like Amps for hours. 4Ah means you can draw 4A for an hour. Or 1A for four hours etc.)https://www.amazon.com/gp/product/B073Q48Z95

    Agreed. After a power outage that drains the battery (hopefully the device does it’s job and gets you through the blackout), when power comes back the charger will be putting out 1A - probably at a lower voltage than 3.7v. But your boost regulators are drawing more than an amp. Which means... you’re going to continue to discharge the battery.In fact, starting out with a full battery, it will discharge during use, even if charger is plugged in.(for me, it’s easier to convert everything to watts, then you don’t have to keep putting voltages into your calculations.).in this case, you’re charger is putting in 5W.your router (if it really draws an amp at 12v) is drawing 12W.As Frarugi87 points out, the math just doesn’t work for using it as UPS.The router would need to draw less than about 0.…

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    Agreed. After a power outage that drains the battery (hopefully the device does it’s job and gets you through the blackout), when power comes back the charger will be putting out 1A - probably at a lower voltage than 3.7v. But your boost regulators are drawing more than an amp. Which means... you’re going to continue to discharge the battery.In fact, starting out with a full battery, it will discharge during use, even if charger is plugged in.(for me, it’s easier to convert everything to watts, then you don’t have to keep putting voltages into your calculations.).in this case, you’re charger is putting in 5W.your router (if it really draws an amp at 12v) is drawing 12W.As Frarugi87 points out, the math just doesn’t work for using it as UPS.The router would need to draw less than about 0.25A for the math to work.it will make a very nice power bank, though.

    Nice project!a couple quick comments. The charger may not put out enough juice to charge the battery and power the router. Could be a problem after a power outage. If the battery is really low, it will put out less than 3.7v while it’s charging, slowly going to 4.2v where it should shut off.the charger probably charges at a constant current until you get to 4v.problem is, during charging your router is pulling current from the charger and so is the battery. I don’t know what your router draws or how much current the charger can put out.over discharging a lithium ion cell will ruin it. It looks like your charger may have discharge protection (two + and two - pads) and you wired it correctly. But you should make sure and perhaps mention this issue in your instructable.or you could use a “pr…

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    Nice project!a couple quick comments. The charger may not put out enough juice to charge the battery and power the router. Could be a problem after a power outage. If the battery is really low, it will put out less than 3.7v while it’s charging, slowly going to 4.2v where it should shut off.the charger probably charges at a constant current until you get to 4v.problem is, during charging your router is pulling current from the charger and so is the battery. I don’t know what your router draws or how much current the charger can put out.over discharging a lithium ion cell will ruin it. It looks like your charger may have discharge protection (two + and two - pads) and you wired it correctly. But you should make sure and perhaps mention this issue in your instructable.or you could use a “protected” 18650. They have a tiny circuit under the false negative contact. It prevents over charging, over discharging, and short circuit/over current protection. The circuit is cool. Pull the wrapper off a dead protected battery. There is a thin strip of metal acting as a wire from the positive pole of the battery, down to the circuit.the negative metal circle can be pulled off the actual battery minus and reveal the tiny circuitry.not a bad idea to pay a little extra and get protected cells.Your switch is in the output which is good.have you measured how much current flows out of the battery when the thing is just sitting there, not connected to anything?if it’s significant, you might consider a second switch in the red wire from the battery.(one of the LEDs is on? The two boost converters are on, even though they’re not connected to anything. It’s called quiescent current. What something draws when it’s not actually doing what it’s supposed to do).in your stated use, you don’t need it.but you mention traveling and your pants..itd be a shame to get where you’re going and have a dead power bank.if I could teach you how to twist wires together your cable would look nicer.twisting wires is exactly like how they twist three small “ropes” together to make a larger rope.trick. Solder one end to the connector. Do not solder the other yet!twist the wires tightly together. While you do this, the individual wires will want to “spin” the other way - you have to let them in order for it to work. That’s why you didn’t solder the second connector yet.your case looks like you may get be able to fit a second 18650 (wired in parallel) for double the fun.

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  • Where’d you get the super strong magnets?

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  • Wow, talk about 64GB in a five pound bag!Nice idea, nice design, beautiful implementation.and I t’s not really a dummy drive. It works, right?so you have two selectable drives.the dummy drive is for your “protected work” stuff.the hidden drive is for your NSFW etc. or the manuscript on how you have developed cold fusion...One caution,your drives are identical.the probably present the VID (vendor ID) and PID (product ID) to your os.if they are the same (and you can verify this from hardware manager on one of the pull downs on the drive) I think you risk the os getting confused if you ever switched drives with it plugged in - the system might not notice the change - does it “di-dunk” and then “do-dink”?if so, it probably noticed the drive change, but your not out if the woods.you didn’t eje…

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    Wow, talk about 64GB in a five pound bag!Nice idea, nice design, beautiful implementation.and I t’s not really a dummy drive. It works, right?so you have two selectable drives.the dummy drive is for your “protected work” stuff.the hidden drive is for your NSFW etc. or the manuscript on how you have developed cold fusion...One caution,your drives are identical.the probably present the VID (vendor ID) and PID (product ID) to your os.if they are the same (and you can verify this from hardware manager on one of the pull downs on the drive) I think you risk the os getting confused if you ever switched drives with it plugged in - the system might not notice the change - does it “di-dunk” and then “do-dink”?if so, it probably noticed the drive change, but your not out if the woods.you didn’t eject the dummy drive before switching which can be bad.strongly suggest setting to the desired drive before inserting.eject when done.if you want to change drives, eject the one that’s inserted, code in the second and reinstall.of course eject that one when done.

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  • I don’t see much in the way of “current limiting power supply” on the units you URLed.Do you get much flicker driving them from AC (I do maybe see a bridge rectifier on them)?

    I read all electronics Instructables with trepidation. As a thirty five year veteran designing consumer electronics, I’m always concerned with the safety of projects that are obviously designed by someone who doesn’t know the basics and/or details of what they’ve instructed. Then, it might be copied by a subscriber with even less understanding.Ironically, in all the worst instances of this, we invariably see the author come back fighting if any electrical engineer makes (valid) comments about the post.My hope us that Authors will realize that the Instructables community has a lot of experts on just about every topic.Authors aren’t expected to be experts at every turn (It’d be great if every electronics Instructable didn’t make me cringe...).Should be ready to accept suggestions from other…

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    I read all electronics Instructables with trepidation. As a thirty five year veteran designing consumer electronics, I’m always concerned with the safety of projects that are obviously designed by someone who doesn’t know the basics and/or details of what they’ve instructed. Then, it might be copied by a subscriber with even less understanding.Ironically, in all the worst instances of this, we invariably see the author come back fighting if any electrical engineer makes (valid) comments about the post.My hope us that Authors will realize that the Instructables community has a lot of experts on just about every topic.Authors aren’t expected to be experts at every turn (It’d be great if every electronics Instructable didn’t make me cringe...).Should be ready to accept suggestions from others who might be expert at what the speak.Coming out fighting that you can “touch” it for two seconds - well it’s just silly.

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  • I’m pretty sure the requirement for ID to purchase spray paint is to help discourage “tagging” (graffiti). Though it may be to reduce the use of spray paint for “huffing” (inhaling for “intoxication” high). Which reinforces your concern that it’s toxic...Used in a well ventilated area should prevent inhalation of the toxic VOCs.Once dried, I think spray paint is pretty inert.

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  • That’s odd. I’ve never seen a “copper top” leak/corrode and now use them (or the new quantums exclusively.I’ve seen way too many pink bunny battries leak...When I buy something (like a TV remote) that comes with batteries, I always throw those questionable,ones away and use copper tops.

    The absolute best thing you can do is to buy a small jar of Caig De-Oxit D100.(https://www.amazon.com/CAIG-Laboratories-D100L-2DB-Electric-Cleaner/dp/B0002BBVN2). Buy the small bottle that comes with an applicator brush in the cap.It may seem expensive, but a little goes a long way and it will last you for many years.It prevents corrosion of the terminals. It helps clean corroded ones.You will never have to “shake” a flashlight again to get it to work.Any/every time I install or replace batteries I always put some on the terminals and the ends of the batteries.You can thank me later!

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  • You failed to mention the hardest part.When you reinstall the lifter rod, it has to pass through the hole in the tab at the bottom of the drain plug.Put the stopper in the sink, with the tab towards the “back”.Then insert the lifter rod with it angled slightly downwards (as if the sink handle for it is pulled up a bit.)Wiggle the sink drain handle to ensure correct operation, then tighten the nut holding the lifter ball joint into the drain. Don’t overtighten.NOTE:I myself, would never shove clog like material down the drain. That’s just asking for more complex problems that might/will require a plumber.Warning. Serious grossness factor.There is undoubtedly a large bundle of slimy, smelly disgusting hair caught on the lifter rod.In my family, due to the grossness factor, this is a definit…

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    You failed to mention the hardest part.When you reinstall the lifter rod, it has to pass through the hole in the tab at the bottom of the drain plug.Put the stopper in the sink, with the tab towards the “back”.Then insert the lifter rod with it angled slightly downwards (as if the sink handle for it is pulled up a bit.)Wiggle the sink drain handle to ensure correct operation, then tighten the nut holding the lifter ball joint into the drain. Don’t overtighten.NOTE:I myself, would never shove clog like material down the drain. That’s just asking for more complex problems that might/will require a plumber.Warning. Serious grossness factor.There is undoubtedly a large bundle of slimy, smelly disgusting hair caught on the lifter rod.In my family, due to the grossness factor, this is a definite “dad” thing, (though my hair is not the culprit).Find a way to lift the huge ball of slimy hair out of the drain.I do it before removing the lifter or stopper.Amazon, Home Depot etc. sell these very inexpensive plastic things that are just a thin strip of plastic with “teeth” on the sides. Search “drain zip”.Slide it into the drain alongside the stopper and lift it out. Be prepared to say “ewww” as you remove it with all the slimy biofilm caught in the teeth.After getting the majority out, then remove the lifter and stopper as explained in this Instructable.

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  • I absolutely LOVE this Instructable.It shows a lot of ingenuity and is well presented.I've always dreamed of building a jet engine, though I have absolutely no use for one.Now I feel that I've built one vicariously through you!

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  • When people ask my mom (a "Master Gardener") why their xyz plant died, she always answers,"Well, you either over watered it, or under watered it"."How do I know which?""You really can't tell."

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  • Ah yes. Excellent point.Whenever I see lots of discretes, I can't resist looking for an integrated solution.I looked for a FET solution, but they were all overly complex.

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  • I like the way you did the voltage multiplier.Did you consider using a dual-h-bridge motor driver to replace ALL of your transistors and many resistors? I did some googling and found a part that I think would work nicely. It's a single so-8 package.LV8548MC (or pin compatible LB1948MC).

    oops. so-10 package.

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  • Nice.Where did you get those LEDs (that "stack" so nicely?Did you file them down?

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  • I'm wondering the same thing about US-American pennies.Would the copper plating fuse to the zinc core?

    Cool idea!You might update the Instructable to mention that you're forming brass by fusing zinc and copper.I had no idea how the "silvery" coins turned "golden" until I read the comments.

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  • Thank you for the Instructable.I sometimes use wads or pieces of paper towel.It cures astonishingly fast.It produces a result that can be cut/shaped with a knife or sanded.And I feel that the paper fiber adds strength.

    Thank you for the Instructable.I sometime use wads or pieces of paper towel.It cures astonishingly fast.It produces a result that can be cut/shaped with a knife or sanded.And I feel that the paper fiber add strength.

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  • I'd be cautious about using this technique for actual "pressurized water plumbing".As you can see from the pictures, sand gets trapped in the plastic - which may come out and clog your fixtures.More importantly, there will be some "thin" spots in the tubing after bending which might compromise the integritiy of the pipe for pressurized water.

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  • Interesting "twist"!The cable isn't "waterproof", so some water IS going to get in. I bet that it WILL cause problems over time.Can you put the whole mess (rod, cable etc) in a ziplock bag with most of the air pressed out before submerging it?

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  • Ditto on the RTV.Just don't use "GE Silicone 1" or any other silicone that smells like vinegar.The acetic acid (vinegar smell) fumes emitted during curing will eat/corrode your wire badly.

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  • Doesn't "plant based" oil go rancid eventually?

    Any chance you can post a link to an English explanation of how this works?What makes the "spiky"?Rather than just attraction (like "ferro putty" I have).

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  • Ah yes, and the compiler doesn't always warn you of such mistakesif (x = y)Is way different thanif (x == y)If you use "if (x = y)" by mistake, instead of comparing x to y, it assigns the value of y to x and returns true based on the value of x - after setting it to y (or maybe it returns y, I can't remember, which is a good reason not to do this on purpose.The reason the compiler doesn't give you an error is that it's perfectly valid syntactically. And there are actually cases where you might want to do it (I never do it. It's confusing.)

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  • that "goop" sold for cleaning stuff actually works well on keyboards.You kind of roll it around and mush it into corners and it removes the dust/gunk.

    That "goop" sold for cleaning stuff actually works well on keyboards.It's kind of like "slime" and comes in a ziplock bag. Lasts forever.You kind of roll it around and mush it into corners and it removes the dust/gunk.

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  • Cool, good info.

    Just to see what would happen, I added some baking soda (~50% by volume) to some notSugru.I was wondering if you could "neutralize" the acetic acid.But I figured it wasn't there if it didn't need to be, and I was right.It made an interesting mess.The caulk got thinner in viscosity, turned a milky white.But it didn't even think about curing.Even after a week, it was still the things he gloppy mess.

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  • I think the switching regulator he chose is a much better solution than an LM317 linear solution.In addition to a plethora of other reasons, it won't get hot like the LM317 would.

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  • would it be code compatible?

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  • The small side vents defrost/defog the lower front portion of the side windows - that you look through to see the side view mirrors.

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  • Cool project. I just may buy a photon!

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  • FRKS1904 -WOW!This could not look more AWESOME!

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  • When trying to coat/encase electronics with silicone caulk, I have had problems with the acetic acid (I assume) severely corroding the copper and other metal (ends up looking like a leaked battery). Any suggestions?

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  • Who's a chemist?As a last step, could you switch the container "cathode" to some other material and then change the power supply direction - to "plate" your card?For instance, I imagine you could use a piece of unused PCB material to copper plate it?And you could do it before or after removing the toner - depending on the look you want (the whole card plated, or only where there is no "ink").Granted copper plate might not be a good look (it tarnishes badly/quickly) but maybe another metal is readily available that would work? Like that $1000 gold coin you have :)

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  • Now, that's a great idea! Keeps you from having to blend the second thickness if paper.

    Nice idea.Only thing I'd add:The way you have shown (dry plug pushed into hole), I doubt it has any significant bond between the plug and hole and is relying on the paper alone (I don't think the mud in the hole is going to stick to the dry dusty edge of the plug).If you moisten the the gypsum edges of both the hole and patch plug and rub (by finger or whatever) some mud into the gypsum, you'll get a better bond of the patch plug to the hole.It's (almost) always better to put any type of "adhesive" on both surfaces before "bonding".

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  • Do I need retraining in gyroscopes?In the "video" at the very top of the Instructables - Why does spinning the base cause the gyro to flip?

    Beautiful! Unfortunately, wayyyy beyond my "machining" capabilities (drill, hacksaw, file lol).Most people think you need to control the "attraction" of magnets to make a motor, but often it's easier (especially in terms of commutation) to make a motor based on repelling of magnets.Once "tweaked", does the motor/rotor spin either way? If not, I expect you could "tweak" it so it does...A suggestion/question that might help builders -1 - It wasn't clear to me which end (N/S) of the coil do you want near the magnets? I guess it depends which side of the Hall effect is facing the magnets...

    As you say, quite a trick.Any chance you have a link?

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  • I think they realized that there would be zero chance that they could build it without leaks.And pulling a vacuum in a tube that size of any length would take basically to infinity.The latest plans I saw for the hyperloop had it "relying" on only a "subtle" vacuum.Because Elon Musk is a well respected visionary, I won't tell you what my spell check did to "hyperloop."

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  • Very nice, and well explained.How do you get the seven segment display to shine so brightly through black paper?Is it special paper?Does the color of paper/color of led matter?

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  • Please don't make this your last Instructables based on my comments!!!I was trying to be constructive, and am sincerely sorry if I offended you.You've done cool stuff. Share it. Let others help you improve your designs!That's what Instructables is all about!

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  • Sure, I'd be happy to backup my claims with facts.The datasheet you show is deceptive in that they plotted X only between min and max Vf. They didn't plot from zero volts. In the small range they plot, the line, though more exponential, appears almost linear, but look how steep it is! Current is VERY sensitive to voltage!I've included a datasheet from a single Cree LED (easier to read than serial strings). They also plotted only over rang of Vf. So I filled in the plot. My red line extends to one volt before running out of paper. Notice forward current is near ZERO and the knee I described is clearly visible.You are playing too close to disaster. You will get burned.If you have any further questions, feel free to ask.

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  • That's the second thing about LEDS."Under driving them", below Vf, they do little or nothing.If you're making them light up, you are driving them at Vf.Oh, and as (most) LEDs get hotter, Vf decreases. So if you try to tweak the voltage to get the desired current... As it heats up, Vf goes down, current goes up... Meltdown, slowly dim or last gasp bright flash... Dead.You really MUST understand that LEDs are CURRENT devices and drive them with a constant current source. This needn't be complex - it could be a simple resistor - but it is necessary if you want to make anything other than a flash-bulb.

    Incandescent bulbs are resistive - not completely linearly, but relatively so (resistance changes pretty dramatically with temperature - which is good, makes them self current correcting).You observation about "check valves" is an interesting analogy.Ignore reverse voltage for the moment, because most diodes (except Zeners) are intended to be used in forward bias. Mostly.If you look at the voltage vs current plot of a resistor, it will be a straight line. More voltage, proportionately more current. V=I*R.Most semiconductors behave in non-resistive, non-linear V vs C relationships.If you imagine a "check valve" that "sticks", that's kinda like a diode.Nothing flows backwards. But you need some forward pressure to overcome the "sticking" before any cu…

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    Incandescent bulbs are resistive - not completely linearly, but relatively so (resistance changes pretty dramatically with temperature - which is good, makes them self current correcting).You observation about "check valves" is an interesting analogy.Ignore reverse voltage for the moment, because most diodes (except Zeners) are intended to be used in forward bias. Mostly.If you look at the voltage vs current plot of a resistor, it will be a straight line. More voltage, proportionately more current. V=I*R.Most semiconductors behave in non-resistive, non-linear V vs C relationships.If you imagine a "check valve" that "sticks", that's kinda like a diode.Nothing flows backwards. But you need some forward pressure to overcome the "sticking" before any current will flow. Then, once the valve opens, it presents almost no resistance and as much water as possible can flow... For diodes, the "sticking point" is called Vf (forward voltage).Instead of a straight V/I plot, diodes have what's called a "knee". Current will be a horizontal line at zero up to this Vf, then the plot will go nearly vertical... With quite a sharp "corner" or knee.For a regular diode, Vf would be about ~0.7V. Red LED ~1.7V, white LED ~3.2V etc.Again, below Vf almost no current flows, the LED will be extremely dim or off. Above Vf (even a little), as much current will flow as your power supply can handle!The LED might be rated at 20mA. Your battery can put out a lot more than that!You need at Vf, but you something to regulate the current to below maximum.This can be done with a simple resistor, or a more complex current regulator. If you connect a 20mA white LED to a 9V battery, you'll probably see a brief flash, and then think you got a defective LED... The 20mA spec says all it can HANDLE is 20mA. At nine Volts, a lot more than 20mA will flow (remember our V/I plot?).In a nutshell, if you want to drive a white 20mA LED from a nine volt battery, subtract Vf from 9V, you get 5.8V left over you need to get rid of, and you want everything balanced at 20mA. If you put 290 ohm resistor in there, at 20mA, it will have our desired 5.8V across it, leaving 3.2V for the LED. But - here's the good part - If more than 20mA starts to flow, the resistor will steal more voltage (V=IR), leaving less for the LED, and vice-versa. Things will balance nicely at the knee at ~3.2V and 20mA.

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  • So is it a common ground that causes a problem, or a common power supply?Which gets noisy? Does the amp push noise back on to the BT supply?Can you just use a bunch of capacitors to quiet things out?

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  • I LOVE it.As one who followed the Apollo program as a kid, I've always lived nixies.And while this is wayyy beyond my capabilities, it inspires me to make something.Thanks for sharing!

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  • >>2. If both inputs are included... could both inputs play simultaneously? >>Say like a backing track that you could strum over?>>Absolutely.Absolutely - unlikely.You can't just "short" the two inputs together and feed them to the amplifier.You'd need to make some type of "mixer" circuit. This could be as simple as some resistors, or a more complex circuit involving a "summing" amp.

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  • Fantastic job. And great instructable.Four comments:1: are you at all afraid that glueing the warped side rails in will warp the walnut deck?2: with this type of paper cutter you must be extremely careful with the two blade edges. The one on the handle and the mating edge on the deck. They may not look it, but they are razor sharp. Do not run your fingers down these edges any more than you would a knife blade!3: while cleaning/restoring a cutter, you must be extremely careful not to do anything that will "round" the two cutting edges (right side of deck blade and left side of arm blade). You will ruin it forever. See below for how to remove nicks/sharpen blades.For anyone who wants to restore a quality paper cutter - visit your local elementary school. Back in the corner of the …

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    Fantastic job. And great instructable.Four comments:1: are you at all afraid that glueing the warped side rails in will warp the walnut deck?2: with this type of paper cutter you must be extremely careful with the two blade edges. The one on the handle and the mating edge on the deck. They may not look it, but they are razor sharp. Do not run your fingers down these edges any more than you would a knife blade!3: while cleaning/restoring a cutter, you must be extremely careful not to do anything that will "round" the two cutting edges (right side of deck blade and left side of arm blade). You will ruin it forever. See below for how to remove nicks/sharpen blades.For anyone who wants to restore a quality paper cutter - visit your local elementary school. Back in the corner of the copier room, they will have at least one cutter no one uses. They may welcome your offer to fix it, or offer to give it to you. When teachers cut through staples, it nicks the blades. This causes them to jam and tear paper instead of smoothly cutting it. Nothing frustrates a frazzled teacher more than running off 22 copies of something and then tearing them when they try to trim them. Trust me. My wife is a 28 year veteran second grade teacher. I've tried (often successfully) to refurbish the blades of many cutters they've "junked" because I couldn't stand them throwing these out. Good ones cost multi-hundred dollars.4: with this type of paper cutter you must be VERY careful with the two blade edges. The one on the handle and the mating edge on the deck.-- they are both extremely sharp. And must be for it to work. Do not run your fingers down the edges any more than you would a knife blade!-- you must not do anything (like sanding) that will round the edges at all.-- the only way I have found to sharpen/smooth the action of these:--- remove the nicks (DO NOT really attempt to sharpen. You will ruin it forever).---- making just a few passes with a ceramic (or diamond) knife hone (you will feel it when you hit the nicks and when you've removed them.---- run a ceramic (or diamond) knife hone lightly down the "top" of the metal part of deck. Perfectly flat against surface.---- run hone perfectly vertical along "right" edge of deck plate.---- run hone perfectly flat against left edge of blade.---- run hone down cutting edge of blade, trying your best to match the existing edge angle.

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  • No offense, but - from experience, good engineering is more than, "it worked that one time I tested it." Especially if you're going to make claims and sell it.You need to make sure your design is valid under all conditions, against worst case vendor specs.5V, 1A in the specs has caveats. Caveats you must understand before making promises to customers!My guess is that you got by in your test case, because you didn't have a full 8.2V lipo, and never drew a full amp more than briefly.And you weren't monitoring the OUTPUT voltage. What size lack was it? That'll give us an idea of average load.If you really want to test your spec get five 25ohm resistors (at least 1W each) in parallel on the output. That'll make your 1A load. Monitor the voltage. I'll bet you 99.44% somethings going …

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    No offense, but - from experience, good engineering is more than, "it worked that one time I tested it." Especially if you're going to make claims and sell it.You need to make sure your design is valid under all conditions, against worst case vendor specs.5V, 1A in the specs has caveats. Caveats you must understand before making promises to customers!My guess is that you got by in your test case, because you didn't have a full 8.2V lipo, and never drew a full amp more than briefly.And you weren't monitoring the OUTPUT voltage. What size lack was it? That'll give us an idea of average load.If you really want to test your spec get five 25ohm resistors (at least 1W each) in parallel on the output. That'll make your 1A load. Monitor the voltage. I'll bet you 99.44% somethings going to fail - quickly.First, remember that linear regulators are basically variable resistors. They decrease the voltage - as waste heat. Lots of heat. 3W max, in this case. That doesn't sound like much, but it is when it's coming from a tiny part. I overloaded a linear regulator once enough that the solder melted and it fell off the board!If you look at the specs, you see some interesting things.1 - thermally regulatedIf it overheats, it will "limit" in some way.Maybe decrease output voltage in an attempt to decrease output current.You're not monitoring the output voltage, so we don't know if it's stable at 1A.2 - max junction (silicon) temperature 125dC.3 - thermal impedance of sot23 is 45/90dC/W -> if heat sink tab attached to ground plane.That's the kicker.Thermal impedance is rated in different ways. Junction to case, case to ambient etc.You don't have the heat sink attached to anything. They don't specify junction to ambient w/ no ground plane, but it's certainly MUCH higher than 90dC/W.But for the sake of my explanation, let's assume it's only 100dC/W.Let's say we're in free air, 25dC, no foam etc. We've got over 3W of heat going on. Work backwards. 25 + (3 * 100) is 325dC...The case is going to be REALLY hot, but the silicon inside is going to be VERY ANGRILY hot.So, how would you make this work?1 - today, you can design it as a " quiet" switcher.2 - Use a TO-3 package. They have much better case/ambient impedance.3 - use an etched board with a large, unbroken copper area that the heat sink tab is soldered to. The copper will radiate the heat. Note this still may not be enough!4 - here's what I would consider.You know you're only going to let the batteries go down to ~7V.Dropout voltage of ams117 is 1.3V, so you only need ~6.3V going into it.Between you're battery sense point, and the regulator input add a 1A, 1W (or 2W) diode (regular, not shot toy). That adds a 0.7V drop and wastes almost 1W of your 3W outside the ams117.

    Nice project. Really compact.Not to be a party pooper, but...8.4V - 5V = 3.4V.3.4V * 1A = 3.4WI don't think there is any possibility that your ASM117 sot223 (with the heat sink pin touching, but not soldered to only one, single sided copper pad), would ever be capable of dissipating that kind of heat...(The datasheet says 45-90 degC/W depending on ground plane, of which you have virtually none).Have you tested it at 8.4V/1A for any significant time? Did the AMS117 shutdown/melt (seriously).If nothing else, consider soldering a piece of the largest gauge solid copper wire that will fit through the he holes in your perfboard and "weaving" it up/down through the four vacant holes in front of the heat sink. That'll give you something.Now try to draw an amp. Might work. The wire will…

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    Nice project. Really compact.Not to be a party pooper, but...8.4V - 5V = 3.4V.3.4V * 1A = 3.4WI don't think there is any possibility that your ASM117 sot223 (with the heat sink pin touching, but not soldered to only one, single sided copper pad), would ever be capable of dissipating that kind of heat...(The datasheet says 45-90 degC/W depending on ground plane, of which you have virtually none).Have you tested it at 8.4V/1A for any significant time? Did the AMS117 shutdown/melt (seriously).If nothing else, consider soldering a piece of the largest gauge solid copper wire that will fit through the he holes in your perfboard and "weaving" it up/down through the four vacant holes in front of the heat sink. That'll give you something.Now try to draw an amp. Might work. The wire will get warm!

    I'm No offense, but - from experience, good engineering is more than, "it worked that one time I tested it." Especially if you're going to make claims and sell it. You need to make sure your design is valid under all conditions, against worst case vendor specs. 5V, 1A in the specs has caveats. Caveats you must understand before making promises to customers! My guess is that you got by in your test case, because you didn't have a full 8.2V lipo, and never drew a full amp more than briefly. And you weren't monitoring the OUTPUT voltage. What size lack was it? That'll give us an idea of average load. If you really want to test your spec get five 25ohm resistors (at least 1W each) in parallel on the output. That'll make your 1A load. Monitor the voltage. I'll bet you 99.44% somethin…

    see more »

    I'm No offense, but - from experience, good engineering is more than, "it worked that one time I tested it." Especially if you're going to make claims and sell it. You need to make sure your design is valid under all conditions, against worst case vendor specs. 5V, 1A in the specs has caveats. Caveats you must understand before making promises to customers! My guess is that you got by in your test case, because you didn't have a full 8.2V lipo, and never drew a full amp more than briefly. And you weren't monitoring the OUTPUT voltage. What size lack was it? That'll give us an idea of average load. If you really want to test your spec get five 25ohm resistors (at least 1W each) in parallel on the output. That'll make your 1A load. Monitor the voltage. I'll bet you 99.44% somethings going to fail - quickly. First, remember that linear regulators are basically variable resistors. They decrease the voltage - as waste heat. Lots of heat. 3W max, in this case. That doesn't sound like much, but it is when it's coming from a tiny part. I overloaded a linear regulator once enough that the solder melted and it fell off the board! If you look at the specs, you see some interesting things. 1 - thermally regulated If it overheats, it will "limit" in some way. Maybe decrease output voltage in an attempt to decrease output current. You're not monitoring the output voltage, so we don't know if it's stable at 1A. 2 - max junction (silicon) temperature 125dC. 3 - thermal impedance of sot23 is 45/90dC/W -> if heat sink tab attached to ground plane. That's the kicker. Thermal impedance is rated in different ways. Junction to case, case to ambient etc. You don't have the heat sink attached to anything. They don't specify junction to ambient w/ no ground plane, but it's certainly MUCH higher than 90dC/W. But for the sake of my explanation, let's assume it's only 100dC/W. Let's say we're in free air, 25dC, no foam etc. We've got over 3W of heat going on. Work backwards. 25 + (3 * 100) is 325dC... The case is going to be REALLY hot, but the silicon inside is going to be VERY ANGRILY hot. So, how would you make this work? 1 - today, you can design it as a " quiet" switcher. 2 - Use a TO-3 package. They have much better case/ambient impedance. 3 - use an etched board with a large, unbroken copper area that the heat sink tab is soldered to. The copper will radiate the heat. Note this still may not be enough! 4 - here's what I would consider. You know you're only going to let the batteries go down to ~7V. Dropout voltage of ams117 is 1.3V, so you only need ~6.3V going into it. Between you're battery sense point, and the regulator input add a 1A, 1W (or 2W) diode (regular, not shot toy). That adds a 0.7V drop and wastes almost 1W of your 3W outside the ams117.

    No offense, but - from experience, good engineering is more than, "it worked that one time I tested it." Especially if you're going to make claims and sell it.You need to make sure your design is valid under all conditions, against worst case vendor specs.5V, 1A in the specs has caveats. Caveats you must understand before making promises to customers!My guess is that you got by in your test case, because you didn't have a full 8.2V lipo, and never drew a full amp more than briefly.And you weren't monitoring the OUTPUT voltage. What size lack was it? That'll give us an idea of average load.If you really want to test your spec get five 25ohm resistors (at least 1W each) in parallel on the output. That'll make your 1A load. Monitor the voltage. I'll bet you 99.44% somethings going …

    see more »

    No offense, but - from experience, good engineering is more than, "it worked that one time I tested it." Especially if you're going to make claims and sell it.You need to make sure your design is valid under all conditions, against worst case vendor specs.5V, 1A in the specs has caveats. Caveats you must understand before making promises to customers!My guess is that you got by in your test case, because you didn't have a full 8.2V lipo, and never drew a full amp more than briefly.And you weren't monitoring the OUTPUT voltage. What size lack was it? That'll give us an idea of average load.If you really want to test your spec get five 25ohm resistors (at least 1W each) in parallel on the output. That'll make your 1A load. Monitor the voltage. I'll bet you 99.44% somethings going to fail - quickly.First, remember that linear regulators are basically variable resistors. They decrease the voltage - as waste heat. Lots of heat. 3W max, in this case. That doesn't sound like much, but it is when it's coming from a tiny part. I overloaded a linear regulator once enough that the solder melted and it fell off the board!If you look at the specs, you see some interesting things.1 - thermally regulatedIf it overheats, it will "limit" in some way.Maybe decrease output voltage in an attempt to decrease output current.You're not monitoring the output voltage, so we don't know if it's stable at 1A.2 - max junction (silicon) temperature 125dC.3 - thermal impedance of sot23 is 45/90dC/W -> if heat sink tab attached to ground plane.That's the kicker.Thermal impedance is rated in different ways. Junction to case, case to ambient etc.You don't have the heat sink attached to anything. They don't specify junction to ambient w/ no ground plane, but it's certainly MUCH higher than 90dC/W.But for the sake of my explanation, let's assume it's only 100dC/W.Let's say we're in free air, 25dC, no foam etc. We've got over 3W of heat going on. Work backwards. 25 + (3 * 100) is 325dC...The case is going to be REALLY hot, but the silicon inside is going to be VERY ANGRILY hot.So, how would you make this work?1 - today, you can design it as a " quiet" switcher.2 - Use a TO-3 package. They have much better case/ambient impedance.3 - use an etched board with a large, unbroken copper area that the heat sink tab is soldered to. The copper will radiate the heat. Note this still may not be enough!4 - here's what I would consider.You know you're only going to let the batteries go down to ~7V.Dropout voltage of ams117 is 1.3V, so you only need ~6.3V going into it.Between you're battery sense point, and the regulator input add a 1A, 1W (or 2W) diode (regular, not shot toy). That adds a 0.7V drop and wastes almost 1W of your 3W outside the ams117.

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  • You need feedback.What you're describing might work for a moment, but only a moment.If the magnet gets a tiny bit too far away, it falls. A tiny bit too close - click - it's stuck to the nail.Your technique is like controlling the heat in your house by timing the furnace on/off cycle times. It would work for a moment.As soon as the outdoor temperature changes, the wind changes, the sun comes out, someone comes in the front door etc....... Things collapse.You can see that in almost any control system, you need feedback - in the furnace case, the thermostat has a thermometer that provides that feedback.A sophisticated heating system might cut back on the heat as you approached the target so it wouldn't overshoot. Your car's cruise control doesn't "floor it" when you're below targe…

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    You need feedback.What you're describing might work for a moment, but only a moment.If the magnet gets a tiny bit too far away, it falls. A tiny bit too close - click - it's stuck to the nail.Your technique is like controlling the heat in your house by timing the furnace on/off cycle times. It would work for a moment.As soon as the outdoor temperature changes, the wind changes, the sun comes out, someone comes in the front door etc....... Things collapse.You can see that in almost any control system, you need feedback - in the furnace case, the thermostat has a thermometer that provides that feedback.A sophisticated heating system might cut back on the heat as you approached the target so it wouldn't overshoot. Your car's cruise control doesn't "floor it" when you're below target speed, then drop the throttle to zero when you hit target - treating your throttle like the furnace on/off switch. That would be a rough ride!Look up "PID controllers". Proportional/Integral/DerivativeFor your car's cruise control:Basically, we're way under target speed? Floor it. As we approach target, start to ease off.The further from target, the more it pushes the throttle (P=proportional).How quickly are we approaching the target (I=integral, D=derivative) - how quickly/how much do we ease off.If we do it right, we'll end up with the throttle right where it needs to be to maintain target speed.

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