Replacing a factory rheostat w/ on/off switch, with a generic rheostat - Page 1
Forum section: electronics / beginners

author: Gmakers721@
author_rank: Newbie
timestamp: January 21, 2025, 01:31:46 am
content: Greetings to all! Just joined..I recently bought an LED "neon" sign, with a very simple design... it's several led strips connected with some silver wires all glued to the top of a peice of see-through acrylic. The whole thing is 13 inches around. It has a standard USB Type "A" connector for power, and a thin, round cord that plugs into the sign. Halfway down the cord, is a switch / push-button rheostat, one lowering resistance, the other adding resistance, for about 6 levels of light in all. Plug it in, push the center power button, and it comes on, full brightness, and it can be dimmed from there.The problem, is that when power is removed, the switch resets, and if turned on again, the sign is at full brightness, which I do not want. I would like the sign to stay at the dimmest setting when turned on ad off. And I have a second LED neon sign (made by a different company) that does EXACTLY that, which I turn on and off with a plug-in remote switch. I understand that the voltage and amps are dialed WAY down by the fixture that I plug the USB "A' plug into. I have tried to look up the voltage and amperage on the website (I bought it on Amazon), but did not find them.It will be easy for me to cut the cord on both sides of the existing switch, and then re-attach everything with a different rheostat that does not have a on/off switch on it.Here is the same company, same type of LED neon sign:https://www.amazon.com/Allball-Dimmable-Acrylic-Powered-Bedroom/dp/B0CF97Q8ZQ/ref=sr_1_33?dib=eyJ2IjoiMSJ9.kf6B2DcErPotI4n6RRiHXZW6ZsMSOXmILZ4ugV35_Cha-6SI1dNCP8xET18cnyqynAJHDGTaY6zkLhanXwtmUXSROC5HGVMdkxEPjs0euGkNoWFgMvmvMLidSfxIPA9RUCWLWPnIXVU43yCxXrR4A56YGVsbqp2nUcGEM05P0BdQQON2bMo6OrfxLjsvkD3fTrM1ZG27E4s_j_oEFkMqhm_w2wXoss0_bfapQZAI41qJRKyAFOXBPdF6yx51VWtVOgf3JmnXlV7StxTh9EhfS5IYxTisxXHkWP9L7L_GQA68F7PcCeD_xGazkno44Mh85TSX-UC29Mk5bBpDrYLDSEr9GU-l-ilqUA2dn1bvTT2DvMGp9z9EloN14s0DzgEN_Wx92PjkItINofIK1YTldghjVrAwG1-k_fKLDdk1JfqTqLYkF0Z6qSnheTveRKiD.BvqVBQ_rRdp0m7wiYD0Wm2hJF95JoOVyxZHS0KBjp9E&dib_tag=se&keywords=Allball&qid=1737422923&sr=8-33But I have no idea what type of rheostat to buy that will be effective in this case. Any suggestions?Thank you in advance for your kindness! : )

author: ledtester
author_rank: Super Contributor
timestamp: January 21, 2025, 01:46:35 am
content: Can you post a picture of the rheostat?

author: Konkedout
author_rank: Frequent Contributor
timestamp: January 21, 2025, 03:27:36 am
content: Quote from: ledtester on January 21, 2025, 01:46:35 amGood request. Another idea though; what about using 3 small SPST switches + resistors and to make 2^3 = 8 levels? Probably cheaper and more reliable than a cheap rheostat.You may need to experiment on the resistor values.

author: Gmakers721@
author_rank: Newbie
timestamp: January 21, 2025, 03:52:19 am
content: I can! And thank you! This is about 2.5 inches long. Smooth, with no markings on the back, and no apparent way to get into the thing.Middle button is on/off, top button = "increase", bottom button = "decrease". Fairly simple.

author: Gmakers721@
author_rank: Newbie
timestamp: January 21, 2025, 03:54:36 am
content: Interesting idea! Thank you! I think for my rudementary skill levels, I should probably stick to the shallows, though.

author: Ian.M
author_rank: Super Contributor
timestamp: January 21, 2025, 04:38:21 am
content: Usually LED light control 'pods' are *NOT* rheostats. They typically work by PWM, with a $0.10 MCU controlling the PWM dimming and a MOSFET per colour to drive the LEDs. If it *is* a rheostat, it will get noticeably warm at half brightness, more so than at full or minimum brightness, but I would expect a rheostat to have a rotary knob, control wheel, slider or multi-position slide switch, not momentary push buttons.It may be possible to replace it with an actual rheostat, but as Konkedout has pointed out, rheostats capable of handling several watts of dissipation don't come cheap, especially if you have to buy several because you don't know the required resistance range. I suggest searching for 5V PWM dimmer modules, with a rotary knob, not buttons or touch switches.

author: ledtester
author_rank: Super Contributor
timestamp: January 21, 2025, 05:31:42 am
content: Search Amazon for "5v pwm led dimmer", e.g.:https://www.amazon.com/DKARDU-Lights-Dimmable-Controller-Adjustable/dp/B0B2RC752T

author: Gmakers721@
author_rank: Newbie
timestamp: January 22, 2025, 04:53:14 am
content: Ah! Interesting. Okay... I think I understand...and I apologize for my ignorance.I will look for one of those and try it out! Thank you both so much!

author: Gmakers721@
author_rank: Newbie
timestamp: January 22, 2025, 04:56:09 am
content: Ohmygoodness!Wow, you made THAT easy...Thank You!!!!Ordered!

author: Gmakers721@
author_rank: Newbie
timestamp: January 24, 2025, 04:43:39 am
content: Soo....and update... the rheostate that was suggested to me that I order, worked AMAZINGLY well. It does EXACTLY what I was hoping for, which was to be able to remotely switch on and off the light, and have it maintain it's lowest setting the whole time. Perfect.I am so grateful to all of you for your assistance! Y'all rock!!Thank you SOOOO much!!!