Hi all, I'm trying to control a light that uses a 0-10v control signal, as I can't find much on the actual needs of the 0-10v for the light I want to try to have the signal be true 0-10v, not PWMed. Right now I have an Uno with a Sparkfun MCP4725 to convert from 0-5v PWM to 0-5v true analogue and an LM358 to take that signal to 0-10v. The MCP4725 works fine, when tested with the multimeter I get exactly what is programmed from the Uno, but I can't get the LM358 to work, I know it is wiring and or resistor choice, I've never used an op-amp before and am pretty leery about experimenting with different resistors without damaging something.
The whole shebang is powered by a Mini-360 DC-DC buck converter set to 5v, as I was worried the Uno might not have the juice to handle everything as is.
Below is the schematic I'm working from and a couple photos of how things are connected right now.
You guys have been a great help in the past!! Any help is really appreciated.
Meanwell LED drivers can also use a pot or PWM, in which case you don't need a D/A or opamp.
Always give all the details of a project.
It's a Kessil A360, there isn't much I could find, their website is geared to selling not DIY.
Edit: Just to add more as per Wawa, the light is a Kessil A360, it has two 3.5mm(headphone) jacks, both use a 0-10v signal, one to control intensity, and the other to control color, at the moment I am only concerned with the intensity, I just want to turn it on and off with a dimming effect. In the future I would like to add the feature to turn it off when the sun is out (LDR?), I face north-west and so only get about an hour or two of sun right now.
What is the LM358 supply voltage?
It's getting 5v from the Mini-360
It should be at least 12V.
One characteristic of an opamp is they cannot output more than their supply voltage. And the LM358 can only go within about 1.5 volts of the +v supply so the LM358 cannot put out more than 3.5 to 4 volts.
I agree with Leo, every LED controller of this type I've seen accepts a PWM input.
I think you should get yourself a N-Channel MosFet, like a 2N7000. Connect the:
Drain to the PWM input
Gate to your Arduino PWM output
Source to you Arduino ground and the LED controller control input common.
You could use a small NPN transistor as well.
The benefit is you don't have to create a 10 signal. The controller likely puts out a 10V when the inputs are not connected (you can check this with a voltmeter).
Because you are not inputting a signal (only connecting the two inputs together, there is no risk of damage to your LED controller.
Wait a minute. . .
a MCP4725 is not a PWM to analog converter
it is a I2C DAC.
JohnRob, I'll try your advice, thanks for the super fast help everybody!
If you really want to go true analog for some reason, you would do better to regulate the current rather than the voltage directly to the LED or LED array. There are also op amp circuits to provide constant current sources (in conjunction with a MOSFET in this case, for power). Just in case you were doing some kind of special photography or something like that, need absolute steady light...
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