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Re: Fertilizer pump fix...

>>an LED just light and stay on.
>>It might also be possible to use the stepper motor's pulses to pulse the
>Both darn good ideas.  Certainly worth a try.  I'll open it up and get 
>my tester out and see what the motor is getting.  Sure would be a lot 
>easier to use the motor and unit power rather than provide my own.  That 
>makes me thing...  How about just wiring up one of the motor wires to the 
>ir sensor directly?  Bypass the middleman as it were...

Check the voltage on the windings, and BE SURE you meter measures the PEAK
value. Many meters won't respond quickly enough and their averaging will
result in a reading lower than what was really there. Your best bet is to
try to find a lebel on the motor. You can use ohms law to determine the
size of resistor you need, remembering that a typical LED voltage is 2.1v
with a 20 mA current draw. Thus a 12v supply would use a 12 - 2.1 = 0.02R,
or 495 ohm resistor. 520 ohms is probably the closest "standard" value, so
that's what you'd use in that case.


Waveform Technology
UNIX Systems Administrator