I need an input of 0-20mA into a speed indicator
QuoteI need an input of 0-20mA into a speed indicatorI am thinking more of a car speed indicator. Analog type. Work like an old VOM. A needle meter. Need a current from x to y to move the needle. So you want a circuit from PWM or digital convert into current value ? I am correct ?
@retroleftyOk, I get it. You need to know more details about the OP speed meter, like current, ohms, voltage max, etc. But you agree with me the OP stil need a circuit to drive properly that speed meter from the Arduino. Right ?
But if the indicator was designed for automotive use it might very well have been designed for 12vdc to be able to generate the 20ma top of scale value.
Thanx everyone for your responses! I didn't realise how complicated this is till I read through all of this!The issue is there is no ONE speed indicator but three to four types which this current input should run (Part of project ). So, I guess this will be problematic seeing that the calculations will depend on the specifications for the speed indicators. Yes, an input of 4-20mA is fine. Does having a separate higher voltage source solve the issue of the possibility of the ATMega not being able to push enough current through? (Not connecting it to the Arduino at all.)Thanx again!