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Hey guys. I'm an idiot who puts to much effort into dumb things, and lately, I've been curious about building a custom wireless charging pad. I don't really know anything about electronics at all, other than a course or two I took in high school 15 years ago. I essentially want to re-create the wireless charging pads that cell phones use these days. Here's the question: if I built one sort of large - let's say a diameter of 16" - would the entire surface area within the coil provide an electromagnetic field? And if so, would it be able to supply power to ~40 small receiver coils? (Each ~1" in diameter) Each receiver coil is only attempting to power a small LED akin to these guys https://www.superbrightleds.com/cat/through-hole/ 
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Feb 8, 2019 15:42
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| # ¿ May 8, 2024 19:32 |
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Shame Boy posted:So a wireless charging pad is effectively acting like a transformer with air as its core material. To be at all efficient, the coils need to be resonantly matched with each other, which usually means they have to be around the same size and shape, close together and relatively parallel to each other. I don't think you'd get much out of your single large coil trying to match to a bunch of tiny coils... Dang, ok. I suppose there's the possibility of using a series of small inducer coils on the bottom half, but at that rate it seems like other solutions would be easier. Thanks!
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Feb 8, 2019 16:29
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I'm trying to do some basic led strip lights and I've hit two in a row that I'm having trouble with. I can't tell if it's bad product, or if it's something I'm doing wrong. I ordered this LED strip: (RGB, 5050 120led IP21) https://www.aliexpress.us/item/2251832623526022.html?spm=a2g0o.order_list.order_list_main.11.73411802IGgASW&gatewayAdapt=glo2usa These bluetooth controllers: https://www.aliexpress.us/item/3256805081032487.html?spm=a2g0o.order_list.order_list_main.17.73411802IGgASW&gatewayAdapt=glo2usa I cut the strip on what I'm pretty sure are the cut marks, and connected it all as you see here:  The first timeI did this with, only the red and blue LEDs work. So I returned that, and bought another. This new strip, which is a different product from a different company, with a different bluetooth controller, appears to only have working red diodes. I can't get it to display any blue or green when using the app. I tried swapping to a different controller too, in case that was the issue. Is this LED strip not the product I thought it was? Did I cut it incorrectly? Is there a problem with the way I've got it connected? I want to know if it's my fault before I submit another defective product return to Ali.
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Mar 17, 2024 21:40
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mobby_6kl posted:
I didn't test it because I didn't want to unwind 45ft worth of LED strip. I do have some multimeters, but I use them pretty infrequently. If I wanted to test the diodes, would I test across these pairs? What setting on the multimeter am I using? The one that beeps when there's a connection? 
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Mar 20, 2024 16:59
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I am, but this is just in the example I copied from the curl test, in the actual code I had real valid json
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Hi all. I'm back with some extremely basic questions about troubleshooting. For reference, my previous posts:The Wonder Weapon posted:I'm trying to do some basic led strip lights and I've hit two in a row that I'm having trouble with. I can't tell if it's bad product, or if it's something I'm doing wrong. Since I initially posted this, I've ended up with three separate LED strips from three separate manufacturers, and two separate LED controllers from two separate manufacturers. This is the second LED controller I bought, for reference: (https://www.aliexpress.us/item/3256805081032487.html?spm=a2g0o.order_list.order_list_main.112.28671802GtMaMJ&gatewayAdapt=glo2usa) Every combination of LED strips and controllers is giving me the same result: red works, but the other colors don't. I can't imagine that all three LED strips are defective in the exact same way, and it would be surprising if both LED controllers were causing issues in the exact same way. So I presume I'm doing something that either doesn't work, or is just wrong, but I can't tell what. I hooked up my latest batch as follows: LED strip > 4 pin connector > led controller > usb 5v adapter. (Same thing as in the picture in my original post above) Previously someone in the thread mentioned testing with the diode tester on the LED strip. I don't have that setting, so I tried measuring voltage at the copper pads, but to be honest I don't really know what I'm looking for. Here's my voltmeter, and here's the strip. What exact points do I need to be checking, on what setting, to test the other colors?  
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May 3, 2024 17:26
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kid sinister posted:You can't do it with your multimeter I'm afraid. You need a DMM with a diode test. A diode test basically puts 3 volts out through the probes and measures how many volts return. 3 volts is enough to make most LEDs glow. Most colors will light fully while white and blue LEDs will glow dimly. They like around 3.5 volts to be at their brightest. Ah, well. I will have to see about borrowing one. But testing the strips aside, there's no way I got three strips in a row that all had exactly the same malfunction right? What else is going on here?
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May 3, 2024 19:58
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| # ¿ May 8, 2024 19:32 |
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Gahhhhhhh I knew it had to be something stupid I was overlooking. That's probably it! I will hunt one down and see how I fare. (also drat these 5050 RGB 120LED strips use a lot of power; looks like 5a for a 2m strip)
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May 3, 2024 22:00
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