Steve2381
Senior Member
Hi all
Probably too late in the evening to even think about this... but hey
I have an input that varies from -12.4v to zero (its the voltage from a commercial RGB led controller). The leds have a common 12v supply (well... 12.4v).
Going to stick the input through a in4001, so that will drop a little of voltage off (0.8v?)
How do I read this with an ADC input which is only 0-5v range? I believe I can do it through a resistor network, but whether that is the best way.... I don't know.
I think I take the negative input through a resistor to the Picaxe and then take one resistor to 5v and one to 0v from the same Picaxe pin? What these resistance would be... I have no idea.
Probably a better way would be to use an op-amp (not that I know how to do that either!)
My simplest solution so far?.... Led on the negative supply opposite a light dependent resistor in a sealed tube. Works remarkably well - just a bit laggy
Any advice greatly received.
Probably too late in the evening to even think about this... but hey
I have an input that varies from -12.4v to zero (its the voltage from a commercial RGB led controller). The leds have a common 12v supply (well... 12.4v).
Going to stick the input through a in4001, so that will drop a little of voltage off (0.8v?)
How do I read this with an ADC input which is only 0-5v range? I believe I can do it through a resistor network, but whether that is the best way.... I don't know.
I think I take the negative input through a resistor to the Picaxe and then take one resistor to 5v and one to 0v from the same Picaxe pin? What these resistance would be... I have no idea.
Probably a better way would be to use an op-amp (not that I know how to do that either!)
My simplest solution so far?.... Led on the negative supply opposite a light dependent resistor in a sealed tube. Works remarkably well - just a bit laggy
Any advice greatly received.
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