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n4mwd

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  • n4mwd commented on Frugha's instructable 7 Segment Display Array
    7 Segment Display Array

    You will need a 2K resistor in series with each CLK and LOAD input on EACH MAX7219 or else you will have communication errors. Many of these chips are very noisy and require the resistors to prevent back feeding noise onto those lines.

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  • n4mwd commented on splat238's instructable Neopixel LED Face Mask
    Neopixel LED Face Mask

    Its just as good as any other cloth mask. Just maybe a little cooler and hotter at the same time.

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  • DIY Electric Foundry for Metal Casting (120V)

    I made a similar electric foundry that had plans online a few years back. That one is 220V. I'm glad to see a new approach to electric foundries. For a crucible, I used an old small steel argon tank that the guy at the welding shop said failed its hydro and gave to me free. In my case, it was the perfect size and works fine for aluminum.As others have mentioned, the dust is a killer. Cut and saw this stuff outdoors only. Masks don't help.

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  • Single Sided PCB Home Fabrication (Presensitized PCB)

    I have a Canon color laser printer, but it has the same problem as inkjet printers when it comes to toner transfer. Even though it's toner it still won't transfer. I am going to try this baby oil process next time I make a circuit board. I can make transparencies, but I have to print two of them and then tape them together in order for it to work right. I've had other laser printers that worked with toner transfer with no problem, but the cannon seems to have a different toner formula.

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  • Alexa Controlled Bookshelf Lighting

    I heard that Amazon messed up Alexa so that it doesn't work with home automation any more. How does this one get past their lockout?

    A friend of mine has his whole house set up with zigbee and z-wave light switches and such. He said none of it works any more with Alexa.

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  • 3D Printed Thermal Insert Press

    When I had to do my brass inserts, I just threaded them onto a long bolt and heated them up with a propane torch. Then I could precisely press the thing into the plastic. If the back side was open, I could put the bolt through the plastic, then screw on the insert, heat, then pull it through. Doing it that way means that the threads never get covered with plastic. I've heard a lot of people saying to just jam it in there with a soldering iron, but I could never get that to work right. Your rig would certainly help if people want to do it that way.

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  • Pink and Green Domino Machine II

    Very clever piece of engineering.

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  • n4mwd commented on MisterM's instructable 1963 Pi Tourer Game Console
    1963 Pi Tourer Game Console

    Considering how easy it was to remove it from the car, I have to think that it was a favorite among car radio thieves. Good job repurposing it.

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  • n4mwd commented on 陳亮's instructable Arduino Watch
    Arduino Watch

    Have you looked at paper white displays? If so, what was your opinion of them for this type of application?

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  • n4mwd commented on 陳亮's instructable Arduino Watch
    Arduino Watch

    How long does the battery last and does it charge through the USB port?

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  • Make Your Own Tiny Camper From Scratch

    The reality is that when campers have any signs of rot, they are usually rotten to the core. Stripping them to the frame and rebuilding them is the only proper way to go unless you want to use it for a chicken coop like I did.

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  • ESP32 Weathercloud Weather Station

    Yes, 0.163mA average current consumption would be really awesome. A solar powered unit would be autonomous and would be much easier to install - say at the top of a pole. You would only need gsm if you were installing it in the middle of a field somewhere - for example, a farmer that wants to check the weather conditions of his crops. Where I live, in South Florida, we can have hurricanes that knock out the power and that is when you want weather data the most. But if you only draw less than 1mA, then a simple battery backup would work just as well as solar. A single 18650 would last about a year on a charge.

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  • ESP32 Weathercloud Weather Station

    Pretty cool, but the high current draw bugs me. Maybe that can get fixed in version 3.0. A station like that really screams solar panel so it could be 100% wireless. A half amp draw is just too much to be practical for solar considering the size of the weather station. Would it be possible to power the sensors selectively with FETs? So like instead of constantly checking the temp, maybe just power the sensor every 15 minutes just long enough to take a reading? So if you could get the average power draw down to 40mA you could power it with an 18650 for 2 days in the event of cloudy weather preventing the solar panel from working at its rated output. Then it would only take a 2 amp solar panel and one hour of direct sunlight to recharge the battery to its full capacity. Just thinkin…

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    Pretty cool, but the high current draw bugs me. Maybe that can get fixed in version 3.0. A station like that really screams solar panel so it could be 100% wireless. A half amp draw is just too much to be practical for solar considering the size of the weather station. Would it be possible to power the sensors selectively with FETs? So like instead of constantly checking the temp, maybe just power the sensor every 15 minutes just long enough to take a reading? So if you could get the average power draw down to 40mA you could power it with an 18650 for 2 days in the event of cloudy weather preventing the solar panel from working at its rated output. Then it would only take a 2 amp solar panel and one hour of direct sunlight to recharge the battery to its full capacity. Just thinking out loud.

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  • I didn't find anything on ebay, but I did find several complete seats from china. So when the time comes, I may have to buy some seats and cannibalize them for their foam. I also found this website: https://itstillruns.com/kind-foam-used-motorcycle-...Which suggests that the dense foam used in motorcycle seats is called "closed-cell, polyethelene foam". I have a Ninja which sits fine for the first half hour, but then transforms into a razor blade after that. On trips, I have to plan to stop every 20 minutes to walk around the bike. I was thinking about making a custom touring seat that was shaped more like a bucket seat for better long term support. That would mean extra foam and not just what it comes with. I found this photo online which is pretty much what I want to bu…

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    I didn't find anything on ebay, but I did find several complete seats from china. So when the time comes, I may have to buy some seats and cannibalize them for their foam. I also found this website: https://itstillruns.com/kind-foam-used-motorcycle-...Which suggests that the dense foam used in motorcycle seats is called "closed-cell, polyethelene foam". I have a Ninja which sits fine for the first half hour, but then transforms into a razor blade after that. On trips, I have to plan to stop every 20 minutes to walk around the bike. I was thinking about making a custom touring seat that was shaped more like a bucket seat for better long term support. That would mean extra foam and not just what it comes with. I found this photo online which is pretty much what I want to build. It diverts more of the rider's weight to his thighs.

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  • n4mwd commented on zaphodd42's instructable Arduino Fireflies

    Can't wait for Arduino Fireflies 2.0.

    I remember there was a book on LEDs by Forrest Mims. In that, he drilled a hole down the center through the plastic of the LED and then glued in a glass fiber. There is some light leakage around the outside of the fiber, but you can paint it with aluminum spray paint if it bothers you. The ends are where most of the light is and, like the other poster said, you can use a blob of hot glue to make a diffuser. I don't know how far they will reach though. If hot glue doesn't work, little bits of a Styrofoam cup will.

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  • Any idea where one could purchase motorcycle seat foam? The stuff at the craft store is too squishy. Motorcycle seat foam is very dense and closed cell.

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  • n4mwd commented on zaphodd42's instructable Arduino Fireflies

    Unless the copper wires are waterproof, the weather will eventually get to them and corrode them out. Unless you are using really thick wires.

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  • n4mwd commented on zaphodd42's instructable Arduino Fireflies

    Interesting to watch. Another design possibility would be to use thin fiber optic fibers with all the LED's in the box. That way they wont be susceptible to corrosion as bad.

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  • n4mwd commented on ejmastnak's instructable Save a Burned Pot

    I was going to say the same thing. You forgot the "Put on Rubber gloves" step. That is very important or else it will eat your skin and you might not realize it for several days. Anyhow, Easy Off works really well - especially for carbonized build up. Its also good for cleaning drip pans on electric stoves.

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  • That's 15c plus the cost of the PCB plus the 7 seg display. On ebay, for $1.40 you can buy the 8 digit 7 seg display with the counterfeit Max7219 already built and ready to go. It still needs two 2K resistors to make it work properly. The WS2811 would be a good option for when you only need one or two digits. The MAX chip uses a SPI-like interface. SPI is not as error free as NRZ, but its better supported.

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  • How do the passwords get from the deivce into a web browser?

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  • n4mwd commented on Nikus's instructable DIY 3D Printed Dremel CNC

    This is a very good design. I think your printed corners are awesome.

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  • n4mwd commented on jones424's instructable AMF Pedal Car Restoration

    No problem when I was little, but as my legs grew they hit the dash board as I pedaled.

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  • n4mwd commented on jones424's instructable AMF Pedal Car Restoration

    I had one as a kid. Loved it. As I grew up I remember it cutting my legs as I pedaled - so watch out for that with your son. That is probably why they stopped making them in favor of the Big Wheel.

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  • I have to say that this is the first home made motion picture camera that I have seen. Some of those old books have really cool stuff in them. I remember building an X-ray machine that I found in one of them when I was 12 using a diode tube and car spark coil for power. Worked good too. I used photo paper and longer than usual exposures.Back then, I could pick up a Kodak TriChem Pack for about $1 and it had all the chemicals necessary for B&W film. These days, most B&W film is fake and uses the C41 color process for development. But that also means that if you can find a lab that is still in business, you can just send it off.The main problem is the cost of the film, but I guess you already figured that part out. I can't wait to see your home made photo chemical instructabl…

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    I have to say that this is the first home made motion picture camera that I have seen. Some of those old books have really cool stuff in them. I remember building an X-ray machine that I found in one of them when I was 12 using a diode tube and car spark coil for power. Worked good too. I used photo paper and longer than usual exposures.Back then, I could pick up a Kodak TriChem Pack for about $1 and it had all the chemicals necessary for B&W film. These days, most B&W film is fake and uses the C41 color process for development. But that also means that if you can find a lab that is still in business, you can just send it off.The main problem is the cost of the film, but I guess you already figured that part out. I can't wait to see your home made photo chemical instructable.

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  • Will this work with the ESP-01S? How much RAM and Flash does it need? The ESP-01S has 1MB Flash.

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  • Its just a case of vimeo not having very bright programmers. I can play youtube videos with no problem. If it was a firewall issue, it would be far better to simply say "Hey, port 1234 seems to be blocked". The only way I can watch vimeo videos is to download them and then play them locally. As such, unless I'm really interested, I don't bother. Disabling the windows firewall doesn't help.

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  • They do have controller chips on them and there is no noticeable flicker on the 120V 60 Hz units. At 50Hz, it might be a different story. On mine, there is a tiny smt cap and a tiny bridge rectifier. The surface is covered with a gel like substance that makes probing it impossible without damaging it.I did not buy from the guy in the link, but mine are similar. You can see the bridge rectifier and cap in his photos as well. The controller chips are the little 8 legged things. The cap is the little beige thing and is probably about 20uF guessing by its size.

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  • They make mains powered LED modules, but they still require heat sinks. Using a mains powered module saves a ton of extra components. I bought a bunch of 50W modules and found that they only draw 25 watts so beware. Still very bright though. Not sure how many lumens, but its usually about 100X the number of watts actually consumed. Here is a link to a random seller on ebay (I've never dealt with him) who sells the mains powered LEDs: https://www.ebay.com/itm/Smart-IC-LED-COB-Chip-20W...If running from 12V is the goal, you can easily add a $10 inverter to the back side.

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  • I hope the link is helpful, but if not, it wouldn't be that hard to write a program to convert gerbers into gcode the way you want it. Gerber and gcode are similar, but not exact.I can think of complexities that I don't know if the software handles properly. For example, in Gerber, the command would say "Draw a fat line from point A to point B." In gcode, it would have to draw the outline of a fat line and then fill it in.I totally agree with you that its better to make a prototype at home rather than to order it from china, wait 3 weeks, and then find out you made a mistake. I recently had to go through three different home made prototypes on a board before it was ready to send to china. I needed 25 of them so it would have been very painful to find out I did it wrong aft…

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    I hope the link is helpful, but if not, it wouldn't be that hard to write a program to convert gerbers into gcode the way you want it. Gerber and gcode are similar, but not exact.I can think of complexities that I don't know if the software handles properly. For example, in Gerber, the command would say "Draw a fat line from point A to point B." In gcode, it would have to draw the outline of a fat line and then fill it in.I totally agree with you that its better to make a prototype at home rather than to order it from china, wait 3 weeks, and then find out you made a mistake. I recently had to go through three different home made prototypes on a board before it was ready to send to china. I needed 25 of them so it would have been very painful to find out I did it wrong after a three week wait and a good size hole in my wallet.Its a bit harder to make double sided pcb's which is what my board was. You mentioned that you tried the routing method of making pcb's with the 3d printer. Probably wouldn't be that hard to modify the router hardware to make a PCB drill out of what you already did. That way, when you plot with the pen, you can adjust it until the alignment with the holes is perfect.

    I hear you about the projects stealing time. I've been working on building my Hypercube Evolution for over 6 months now and I'm 99% complete. Seems like everything else gets in the way of working on it. I'm waiting on replacement thermistors as the first batch from china turned out to be fakes.Once I get it working, I'll be able to experiment with various ways of making PCB's. Thanks for taking the time to write this instructable.

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  • I like Ferric Chloride too. It seems to produce the best results. I tried the home made stuff with Hydrogen Peroxide and Hydrochloric acid, but I found that it undercut my traces too much. Ferric Chloride seems to do a lot better for what I do.I found a gerber to gcode converter that might be of use to you on github: https://github.com/pcb2gcode/pcb2gcode I've never used it, but the source code is provided.I use negative photoresist film exclusively because its consistently high quality and predictable. The trick to applying it is to clean the board really good and apply the film underwater. Then run it through a laminator to make it stick.The guy in the video below has inspired me to try to design a laser photoresist exposer. I wouldn't be using steppers like he did, but I do thin…

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    I like Ferric Chloride too. It seems to produce the best results. I tried the home made stuff with Hydrogen Peroxide and Hydrochloric acid, but I found that it undercut my traces too much. Ferric Chloride seems to do a lot better for what I do.I found a gerber to gcode converter that might be of use to you on github: https://github.com/pcb2gcode/pcb2gcode I've never used it, but the source code is provided.I use negative photoresist film exclusively because its consistently high quality and predictable. The trick to applying it is to clean the board really good and apply the film underwater. Then run it through a laminator to make it stick.The guy in the video below has inspired me to try to design a laser photoresist exposer. I wouldn't be using steppers like he did, but I do think he has the right idea to use a raster scan instead of using gcode. Gcode is good for a plotter like yours, but a laser exposer would leave little cracks if it tried to draw this with gcode. Another issue with his comments is that he seems overly concerned about ambiant light ruining his print. However, in my experiments, ordinary incandescent lighting will not expose the film even when put right next to the bulb. It exposes only with UV.

    Nicely detailed. I would be wondering how many boards you can do with one pen before it either runs out or deforms. I'm not sure what's so bad about the chemicals used to process the negative photoresist film. Sodium carbonate for developing and sodium hydroxide for stripping. Both safe enough to pour down the drain. Just don't stick your finger in it.

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  • Those chips work good for LED strips which is what they were intended for. A MAX 7219 chip, which I frown upon, can handle eight 7-seg + DP displays. Those are about $20 for 50 but they have problems. Mostly because they are counterfeit. I suspect the Ali WS chips are also. Might work - might not. Still, the Busy Bee is a single chip solution that can handle up to 3 digits and provide error corrected communication. That was the biggest problem with the MAX chip, it was basically a big shift register and any noise that got shifted in also got shifted out to the next chip in the line. The more chips, the more chance of an error creeping in to the data stream. I briefly looked at the WS datasheet and suspect that it works the same way.

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  • Does the laser exposed paint simply go up in smoke or is there an issue with ashes getting in the way of the laser's next pass?

    With the right tools and equipment its usually faster to make them yourself. However, when you figure the cost of the bare board, the cost of whatever mask you use, and the cost of chemicals, the chinese board shops are only slightly more than that and deliver, usually within 2 weeks, a superior board with 2 sided solder mask, plate through holes, and 2 sided silkscreen. I personally like to make the first board myself. That way I'm not waiting 2 weeks to find out I made a bad mistake.

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  • I don't think the WS2811 chips are the best choice for a single 7 segment display. You need three of them at a cost of $1.50. A better and cheaper, but not easier, choice would be to use a single $0.60 Busy Bee (EFM8BB10F8G-A-SOIC16). The Busy Bee is an 8051 mcu with everything built in. It has 13 IO lines that can drive the 7 segment display directly - only a single resistor and a pair of power coupling caps are necessary. Actually, you could actually drive two multiplexed digits plus the decimal point with it. That particular MCU is in a giant 16 pin soic so its really easy to solder. Because the Busy Bee is a MCU, you can program whatever communication protocol you want including bidirectional with error correction. It has built in hardware CRC to make that easier.I just comple…

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    I don't think the WS2811 chips are the best choice for a single 7 segment display. You need three of them at a cost of $1.50. A better and cheaper, but not easier, choice would be to use a single $0.60 Busy Bee (EFM8BB10F8G-A-SOIC16). The Busy Bee is an 8051 mcu with everything built in. It has 13 IO lines that can drive the 7 segment display directly - only a single resistor and a pair of power coupling caps are necessary. Actually, you could actually drive two multiplexed digits plus the decimal point with it. That particular MCU is in a giant 16 pin soic so its really easy to solder. Because the Busy Bee is a MCU, you can program whatever communication protocol you want including bidirectional with error correction. It has built in hardware CRC to make that easier.I just completed a large chain of 8x8 matrix displays that were daisy chainable like your 7 seg displays are. I used, and regretted it, a set of MAX7219 chips. The problem was that the serial communication broke down with longer chains. I finally found a way to fix it, but its still not perfect. If you use bidirectional communication with error correction then you don't have that problem.

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  • I would love to see this running. Can you post a video on youtube? Vimeo never plays right. All I get is "Player error: The player is having trouble. We’ll have it back up and running as soon as possible." And of course they never do.

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  • n4mwd commented on kenmacken's instructable Full Size RC Car

    cool project. Would be nice to have come collision sensors so that it can back out of a parking spot and come pick you up at the front door of the store when its raining without hitting anybody.

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  • In case someone else hasn't mentioned this, but HF had a trailer recall so they were off the market for a while. The lights were bad as well as the rims. Supposedly they are all fixed now.

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  • I think he means a version of your washing machine that runs by a hand crank or wind up spring or something like that.I remember seeing a movie once where an inventor had ropes with pulleys attached to the ceiling that he would pull down and a weight would go up. As the weight descended, it would power a washing machine or ceiling fan or whatever. Kind of like how a grandfather clock works. The movie was fiction, but many of the technical concepts were real.

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  • Very well done instructable. Plenty of details so people can actually build one. Nice!

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  • Does the AC in close proximity to the thermistor wires cause any trouble with the ADC used for the thermistor?

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  • n4mwd commented on liquidhandwash's instructable Robot Chicken Door

    I made an automatic chicken door about 20 years ago from the motor used to actuate a car's pop-up headlights. The motors were designed to spin exactly 180 degrees and stop. They also had a good bit of torque. When I added a timer, and the door opened automatically in the morning and closed automatically at night. I never used a photocell, but that was on my list of future improvements that never got done.

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  • Very cleaver. Reminds me of some of the stuff Forrest Mims would come up with.

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  • n4mwd commented on fixxit's instructable DIY Vehicle Tracker

    If you have an amateur radio license, another option is to use APRS. You buy the hardware and then just use the ham packet radio network. However, the issue of powering the thing on a bike battery is still relevant.https://en.wikipedia.org/wiki/Automatic_Packet_Reporting_System

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  • n4mwd commented on fixxit's instructable DIY Vehicle Tracker

    Based on the numerous negative reviews about FredomPop, it might be better to go with H2OWireless or T-Mobile. H2O offers a by-the-minute prepaid plan that runs on AT&T's network. T-mobile has a $3/month prepaid plan. That fact that FreedomPop rams you directly into an "Activate Now" screen when you are only shopping around says they are less than honest right there.

    Just thinking out loud, but if you get a sena or uclear for your helmet, you can make and receive calls on that phone. Use a google number to link all your phones together.

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  • Thanks for the detailed instructions on how to set up a Pi Raid. One question, if you don't mind, is it possible to set up a Pi Raid such that there are two drives, one is a mechanical mirror drive, and the main drive is an SSD? The reason for that would be two fold. 1) The different technologies greatly reduce the odds that both will fail at the same time; and 2) the SSD could be used for increased speed.

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  • The odroid xu4q might be able to do raid. It supports usb 3.0 and 1G ethernet. Its 8 cores at 2GHz. An $8 sata adapter would be required for each drive. The xu4q is about 2x the price of the pi3 though.

    What about RAID? I like the idea of a serviceable NAS, but data integrity is also important. Can the PI handle RAID?

    The USB 2.0 spec runs at 480 Mb/s, whereas the Wifi -G runs at about 450 Mb/s. Depending on the overhead, it should be able to keep up with Wifi speeds.

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  • Its a great build but seems a bit over complicated. Have you considered a sun shower? Its basically a bag of water you hang in the sun for 5 minutes and then take your shower. Since the bag is portable, the shower part can be anywhere. No pump or electricity because it gravity feeds.https://www.amazon.com/Stearns-Sun-Shower-Portable/dp/B000NVDFOO/

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  • Seems like if you need AC that bad, a pop-up camper would be a better choice.

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  • I was hoping to find a grid tied inverter that would automatically switch off instead of back feeding the grid when solar output was greater than power consumed. Around here, they don't allow grid tied inverters to back feed the grid without a special permit. The meters are now smart enough to detect it too. I was thinking about wiring something to the AC compressor (4KW) and just allow the inverter to work when the compressor is running. If the grid tied inverter didn't have such an input, maybe just a relay in series with the solar panels.

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  • The dry film photoresist is way easier to apply and a lot cheaper. Develops the same way. However, after development, I suggest a quick dunk in a stop bath made from teaspoon of vinegar and a cup of water. This prevents the sodium carbonate from contaminating the etchant.

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  • Dry joint compound would be my first guess. Its also used for the slurry when making lost wax castings.

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