EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: symbianas on January 18, 2023, 05:33:14 pm
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Hi, I have bought unknown programmable (ws2811/ws2812...) LED strip which has 3 wires (black, blue, green).
Its not very clear which is "positive" which is "negative" and which is "data in". Is there any way to guess/test without unwrapping black taped LED strip? Also not damaging it?
In third image I have tested which wire is soldered to which part of LED strip.
Black - negative?
Blue - data in?
Green - positive?
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The cap should be tied to VCC and GND, so I would also guess black is ground, green is VCC, and blue is data. You could check by connecting to a PSU with a very low current limit (<50mA) and then feeding in enough data to light the first LED only. If you get it wrong, there shouldn't be enough current to fry anything.
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Yes!!! We have guessed correctly! Its working! Thanks! :)
The marking next to LED (green triangle) is not that clear though.
Is there a way to guess voltage?
Its working from 3.3V quite bright, I think it might be 5V driven, but not sure how to test?
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Excellent, glad it works! You could try cautiously raising the voltage while keeping the current limited to a small range… again, just light one LED so that you only need little current and see what happens if you raise to 5V. Then again, if it works at 3.3V, why mess with it? :)
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Excellent, glad it works! You could try cautiously raising the voltage while keeping the current limited to a small range… again, just light one LED so that you only need little current and see what happens if you raise to 5V. Then again, if it works at 3.3V, why mess with it? :)
Its easier to find power supply of 5V.
I think I found equivalent to my led strip:
https://www.aliexpress.com/item/1005004455070681.html?spm=a2g0o.productlist.main.1.2d08246cRNofC2&algo_pvid=f31db506-cf40-4d72-ab8a-b4babed61591&algo_exp_id=f31db506-cf40-4d72-ab8a-b4babed61591-0&pdp_ext_f=%7B%22sku_id%22%3A%2212000029232572388%22%7D&pdp_npi=2%40dis%21EUR%2125.01%2117.51%21%21%21%21%21%40210219c216740757955497261d0689%2112000029232572388%21sea&curPageLogUid=XM80M8WbpCa2 (https://www.aliexpress.com/item/1005004455070681.html?spm=a2g0o.productlist.main.1.2d08246cRNofC2&algo_pvid=f31db506-cf40-4d72-ab8a-b4babed61591&algo_exp_id=f31db506-cf40-4d72-ab8a-b4babed61591-0&pdp_ext_f=%7B%22sku_id%22%3A%2212000029232572388%22%7D&pdp_npi=2%40dis%21EUR%2125.01%2117.51%21%21%21%21%21%40210219c216740757955497261d0689%2112000029232572388%21sea&curPageLogUid=XM80M8WbpCa2)
So it seems that its:
5V
110cm (148LEDs)
SMD 2020 WS2812C LED
Chip: San'an
Power: 0.1W/LED
Now whats left is to find out how much Amps do I need drive this thing.
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I would guess around 3A if all the LEDs are on at full brightness, plus whatever is needed to run the MPU that controls the string. (.1W / 5V = 20mA per LED). Good luck!