Timeline for Flickering LED strip when dimming
Current License: CC BY-SA 4.0
19 events
| when toggle format | what | by | license | comment | |
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| Feb 25, 2021 at 10:30 | comment | added | Jannebozz | @user253751 This does not seem to be the case here. For some reason, I never saw the flickering on the first 10 LEDs or so. After adding a level shifter the problem is gone. | |
| Feb 25, 2021 at 9:57 | comment | added | Criticizing Israel not allowed | Note that each LED re-creates the signal. If there's a signal integrity issue, it's before the first LED and they should all flicker. If it's worse down the strip, it should be a power issue. | |
| Feb 25, 2021 at 9:33 | answer | added | Jannebozz | timeline score: 2 | |
| Feb 23, 2021 at 7:20 | history | edited | Jannebozz | CC BY-SA 4.0 |
Added scope shot
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| Feb 22, 2021 at 11:21 | comment | added | Jannebozz | Added an update above with some lastest testing/conclusions | |
| Feb 22, 2021 at 9:45 | history | edited | Jannebozz | CC BY-SA 4.0 |
added 955 characters in body
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| Feb 21, 2021 at 15:51 | review | Close votes | |||
| Feb 28, 2021 at 3:04 | |||||
| Feb 21, 2021 at 15:46 | comment | added | jannebozz | Thanks for the replies. I will continue some testing tomorrow, using a scope to see what’s really going on. Might also need to reconsider adding more power connections. Hopefully it’s a bit ringing that causes this... | |
| Feb 21, 2021 at 15:35 | answer | added | D.A.S. | timeline score: 2 | |
| Feb 21, 2021 at 14:49 | comment | added | D.A.S. | This is a transmission line signal integrity problem that may be solved by attempting to dampen each end with something close to the cable impedance. I assume load current * cable resistance drop is insignificant and a load cap has been tried | |
| Feb 21, 2021 at 14:40 | comment | added | user263983 | @SimSom no, it will not work at lower frequency. May be 750kHz, but it not a big difference. | |
| Feb 21, 2021 at 14:40 | comment | added | bobflux | It's probably a power supply issue, I agree with Passerby | |
| Feb 21, 2021 at 14:36 | answer | added | user263983 | timeline score: 3 | |
| Feb 21, 2021 at 14:32 | comment | added | user1850479 | If it is a signal integrity issue, you could try putting a ~100ohm resistor at the start of the data wire to reduce rise times, which will make you less sensitive to the wire length on the data line. Might also be worth measuring the output of that controller if you can to verify it really is 5v as required for the ws2812. | |
| Feb 21, 2021 at 14:29 | comment | added | Sim Son | Is there a chance to decrease the data rate? WS2812 should work at far lower speeds | |
| Feb 21, 2021 at 14:27 | comment | added | Abel | Power and signal integrity are the same from the standpoint of the LED. There is a minimum voltage for an LED to produce light. If it is met while current is passed through the LED, the energy will make light and heat, otherwise just heat. There's a little bit of capacitance and resistance everywhere; if the capacitance and resistance in what feeds the LED ends up smoothing your AC LED blinking (dimming for LEDs is just blinking fast) below that minimum voltage, you get what you observed. | |
| Feb 21, 2021 at 14:24 | comment | added | Passerby | Add a 1000 uF cap close at the start of the led strip and see how it reacts. | |
| Feb 21, 2021 at 14:18 | review | First posts | |||
| Feb 21, 2021 at 23:15 | |||||
| Feb 21, 2021 at 14:08 | history | asked | Jannebozz | CC BY-SA 4.0 |