dry contact variable resistor

I have been struggling for about a year now trying to control 0 - 10 volt led lights with my Arduino. The Lights are 120 volt and the driver supplies the 10 volts. By reducing the resistance from 50k ohms (or more) to 0 the light goes from full bright to full dim.

I can not change the driver. I have tried a 16 volt digital pot and was not happy with that as once and a while it would get instantly super hot.

The load is supposed to be 1ma but never over 2ma.

I was able to dim with a dc solid state relay and control that with pwm. This worked great until the manufacturer updated the driver. Now it is unreliable.

It would be so cool to have a resistor act like a dry contact. Have it adjustable like a digital pot. Can any one help me with my project?


Why not use PWM instead of a voltage.

Try an opto coupler.
Opto transistor connected to DIM+ and DIM- of the LED driver (collector to +).
Opto LED, with 1k current limiting resistor to PWM pin/gnd of the Arduino.
Use pin 3, 9, 10, or 11 (all ~500Hz).

Which driver are you talking about?

We do need to know more about the lights and "driver".

Typically, 0-10V dimming works with 10V PWM so you just need a little transistor driver circuit like [u]this[/u] to boost the Arduino's 5V PWM. (Note that's an inverting circuit so you'll have to invert your logic.. 0% PWM is 100% brightness, etc.)

Since a pot/resistor works, that means the 10V supply is built-in already and you can leave-out R2.

If you actually need a varying DC voltage, you'll need voltage source slightly-higher than 10V, you will need the pull-up resistor (R2), and you can add a [u]low-pass filter[/u] to convert PWM to "analog" DC.

I was able to dim with a dc solid state relay and control that with pwm. This worked great until the manufacturer updated the driver. Now it is unreliable.

Is it supposed to work with PWM?

What happens with the solid state relay? Solid state relays can "leak" with low-impedance, low-current loads. It might work if you add a pull-up resistor or a "load resistor", or just some different wiring.

I agree with DVDdoug,

In addition, I've seen a number of this type of controller have a single input (plus ground) and it accepts either PWM or Ana log or a pot.

If yours takes PWM I would:

  1. test the device.

The device I've used would be 100% when the control input is open and off when the control inputs are shorted to each other.
If you have a resistor between 2k to 5k ohms, connect it across the control inputs you should get some output between 0 and 100%.

  1. In DVDdoug's transistor ckt you would eliminate the R2 and Vcc, connecting the collector to the input of the controller's control inputs.

You will likely not need a low pass filter.

This “10-volt (Meanwell) mains powered LED driver” question comes up every few monts or so.
I have recommended an opto coupler instead of just a transistor (post#1) to be on the safe side (mains powered device). If you do a seach on this side you will see that that recommendation always has worked.
It would be nice to get some feedback from the OP.

Hi. Thanks for all the ideas. I have used some meanwell drivers. They are very cool and most can be controlled by many ways.

The driver I have is Everline D21cc80uvpw-c. The driver is not intended to be controlled with pwm. I tried pwm on the old driver and it worked great. It was just luck.

On a different meanwell driver and light I was able to use a 0-10v power supply controlled by pwm. That worked perfect. It was a little kit I purchased.

What i am trying to do is have the light slowly fade on then fade off. Simulating sunrise for fish.

Thanks for all your ideas so far. I will check out opto couplers.