DMX controlled lightstrip - Page 1
Forum section: electronics / beginners

author: jimbo493
author_rank: Newbie
timestamp: May 07, 2018, 04:03:06 pm
content: So i purchased a cheap LED moving light off of eBay with the intent of breaking it down and using it to control two RGB led tapes and a couple steppers, since that is all it is.I guess i kinda hoped that the LEDs would be running at the same voltage as the strips, bt the strips take 12v and ive only found variable voltage on the mover from about 0-2.8 volts.I was wondering if theres an easish way to use that as a control signal for a 0-12v led driver. Or somehow using one of those IR controllers for them and using the regulation circuitry from that and the control signal from the mover. I want to use the mover so that I can control it over DMX in a theater.Hers some links and images:Mover eBay page:https://www.ebay.com/itm/50W-Stage-Light-Lighting-RGBW-Wash-Remote-DMX512-Auto-Moving-Head-9-15CH-E2G6/361974002221?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649Mover LED board, the connector provides 13.5v and control signals for all 6 LED colors(0-2.8v approx.)https://photos.app.goo.gl/UGG1GdpnBoSPJBLD8IR control board for LED tape:https://photos.app.goo.gl/FpuxeKuTuqRGo37e2I have some knowledge in electronics, but this is really over my head. So much for the simple tack and go.Thanks a bunch,Jimmy

author: james_s
author_rank: Super Contributor
timestamp: May 07, 2018, 04:51:47 pm
content: 2.8V sounds like the typical forward drop of an LED, they are current driven devices so the voltage will be dependent on the characteristics of the specific LED. Your LED strips will have groups of several LEDs in series with a current limiting resistor for each group. It looks to me like there are drivers integrated into the LED board, can you find a datasheet for those chips? The DMX decoder likely puts out logic level PWM signals that you could use to control any LED driver with a PWM input, or just use some mosfets to control LEDs powered by whatever voltage you want. This shouldn't be very difficult but is likely to require a bit of reverse engineering.

author: jimbo493
author_rank: Newbie
timestamp: May 07, 2018, 06:45:02 pm
content: The 0-2.8v signal comes out of the micro on the mainboard attached.The LED board seems to have 6 driver circuits for the 6 different colors in the LED. The SOT23 I can't seems to get a datasheet for.This is what is on the chipCode:M17201D1726HCI assume all the signals are created on the micro, are you saying I could buy a PWM driver and then just take those lines for each color(Could I get an example?)?Do you think the drivers in the IR board are PWM?Unfortunately I dont have an oscilloscope which makes this a bit annoying.Thanks for the help

author: james_s
author_rank: Super Contributor
timestamp: May 08, 2018, 01:02:32 am
content: What did you measure that 0-2.8V signal with? There's a good chance it's not an analog voltage, but a PWM signal that varies in duty cycle. You'd need an oscilloscope to know for sure. If it's PWM you can just drive a transistor or mosfet with it and use that to control the LEDs.

author: Lathe1982
author_rank: Newbie
timestamp: May 10, 2018, 05:24:26 pm
content: thanks a lot for this thread with so many details, photos and links tosteroids online! i found it super helpful as i found lots of useful information. would really appreciate if someone could answer James-s question as i got interested in it myself. thanks!

author: jimbo493
author_rank: Newbie
timestamp: May 11, 2018, 02:41:28 pm
content: I took the data lines from the micro on the mover and ran them to LED controllers mosfets and removed it's micro. I then powered the led board with the 13v and ground from the mover and it works a treat. I'll post pics when I get it all cleaned up. Thanks for your help guys.I used the frequency mode on my multimeter and saw the flunctuations in frequency btw.