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DIY AUTOMATIC SOLAR CHARGE CONTROLLER
Harvesting your own clay, dirty but delightful!
Nice one. voted.This is a wealth of info. I live in Texas, and the Brazos river is at the edge of my back yard. I have found large brick-red clumps of raw, clean clay, and made little smiley faces to dry on flat river rocks, but never knew what I could really do with it. This has inspired me to go collect some and "play" a little more seriously with it. Thanks for the info, and time you took to put it down into a nicely illustrated and easy to read format.
Daisy chain two of these circuits, or figure a way to load balance, to charge two batteries at once. Then you only dump when both are full. Or expand to three or more batteries.Or... Set up another relay and have it charge one until full, then switch over (via relay) to charge the next battery.Or... instead of a battery, run a heating element in a hot water heater. Then use heat exchange to get your energy back out ;)
When I started doing this, I used a dremel tool with a very small drill bit. I forget the size, but I special ordered several that were specifically for this purpose. Later, I got a small jeweler's drill press which worked much better.Getting the passive component holes just right is not very crucial. Just as long as they are "connected" to the required traces and nothing else. For 8 pin DIPs, I always use sockets, and the pins on the sockets (and chips as well if you don't use sockets) are a little forgiving. They can move around a bit (bend, twist, "stretch", etc), and the holes don't have to be perfect. The stuff I do doesn't go much over an 8 pin or a pentawatt type package, but I've never had a problem drilling the holes.Occasionally, the bit will "walk" a little, but that never really caused a problem. One thing to help that is to etch a tiny hole in the middle of the trace where you want the pin to come through. Include it in your mask. Then the lack of copper helps guide the drill bit and keep it from moving around until the hole is deep enough to keep it in place.The biggest problem I had was figuring out what size drill bit to get and use. I'm not at my project bench now, so I can't check them and tell you what I use. The second problem was slightly crooked holes when I used my dremel tool (not perfectly 90 degrees), but that really wasn't a problem.I have actually used a thumb drill (manual pencil shaped drill, similar to an exacto knife with a drill bit on the end) to do the holes in PCBs before, and it did a surprisingly decent job. Went faster than I expected as well. Just press down with one thumb while spinning with the other hand. Put a small piece of cloth over the end so you don't get a blister on your thumb after a while from the friction.I would recommend not worrying too much about the holes, as they are not as hard as you think, and do not have to be as precise as you think. In my opinion, its harder to keep the very thin traces from getting gaps from leaving it in too long. Long live solder bridges!
Lye as an etchant? Did you mix it with anything or just use it "raw"?I have heard of using projector sheets, but never tried it. How well does that work and can you reuse the sheets? I've always used the magazine paper (shiniest and thinnest I can find, with econo-mode off and printer settings to dump maximum toner).
A good recommendation. I do this as well using a Sharpie permanent marker. I do not know what a Dalo pen is, but may be similar. The Sharpie's ink is etch resistant, but can wear out if it is in the etchant too long. On some boards, when I've had weak etchant and it took a while, I had to remove the board and re-color some of the areas multiple times. Some still came out with tiny pin-holes speckled around.
I think he does want to dim it, but the LED panel he has wasn't designed to dim. Using PWM should allow him to dim the panel.Current limiting sure wouldn't hurt, even if its just a current limiting resistor in series. Constant current supply and current limiting resistors are to prevent the LEDs from getting too much current and burning themselves out. I would recommend putting a resistor in there along with the PWM, just in case. I've burned enough LEDs that I always use resistors now.PWM (pulse width modulation) sends quick pulses of voltage instead of a steady DC voltage. This allows you to slow the pulses down and make the LEDs appear to be not-as-bright, when in reality they are simply going on and off at a slower rate. BTW, the on-off pulses are so quick that the human eye can't see it. Also, the pulses allow the LEDs to cool slightly in the off cycle, which prevents them from getting so hot and burning out. However, it is still possible to burn them, so I recommend the resistor. Its cheap protection.LEDs by themselves will take all the current available to them, with no limiting control. Having a resistor in series with them allows you to specify how much current they can have. The value of the resistor depends on the voltage being supplied and the maximum amount of current your LED(s) can handle. For example, with 12 volts and an LED that can handle 30 miliAmps - R=Volt/current - 400=12/.030 - so, a 400 ohm resistor would limit it to .03 amps at 12 volts. I personally would bump that up just a tad, maybe 470 (higher ohms is less current) because LEDs look just about as bright when near (not at) their maximum, but live a lot longer. (FYI, you also have to deal with resistor values, good luck finding a 400 ohm resistor).
I found a solution to the X/Y axis being swapped, at least for me. Using an Uno with a 2.4 TFT LCD Shield. The controller on the shield is covered, so I don't know what it is. Cheapo from China.In SPFD5408_TouchScreen.cpp:Find the lines that say "int TouchScreen::readTouchX(void)" and "int TouchScreen::readTouchY(void)", and then swap the X and Ys. These are at the end of the file, with just one small section after them.That way every time it wants to read what the X coordinate of the touch is, it receives the Y coordinate instead, and vice versa.That fixed swapping the X and Y axis, but now X is backwards (reads high when it should be low). To fix that, find the line (in the same file, towards the middle) that says "return TSPoint(x, 1023 - y, z);" and change it to "return TSPoint(1100 - x, 1023 - y, z);" This is the same fix that other people have suggested. What this does is take the X value of the touch, and subtract it from 1100, which effectively reverses the X coordinate. Example: If X is 25, it should be on the left, because 0,0 is upper left. However, it is registering at the far right instead because X is backwards. If we subtract it from 1100 (or some number close that works for you, experiment), then 1100-25 = 1075. 1075 should be at the far right, but because X is backwards, it registers at the far left. Ta-Da, fixed.
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