Hi All,
Does anyone know of any inexpensive 8 bit single board computers that have at least two relays capable of switching two 24V solenoids (approx. 500ma each)?
Thanks, Fred
Hi All,
Does anyone know of any inexpensive 8 bit single board computers that have at least two relays capable of switching two 24V solenoids (approx. 500ma each)?
Thanks, Fred
I don't, but if circumstances are right it's dead easy to make a suitable solenoid driver with a BJT or a FET.
You need:
If all these conditions are met, then the following circuit will work:
24V + | | .--o-. | | D1 - | ^ | | | | | .-. | | | C| 39 | | C| '-' C| | | '----o | | 100 ||-+ ___ ||Am 09.02.2011 16:10, schrieb fred:
You have to reprogram the microcontroller.
cheers Gunther
Lots of companies make suitable relay boards to go with a ucontroller board:
possibly something here:
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Or to be more specific ...
Maybe this is not exactly what you look for:
-- Tauno Voipio
Looks good. Since resistors are $0.001 apiece, I'd suggest a 100K resistor either from the gate or from the input to ground, so if the uP I/O is floated or the input becomes disconnected the MOSFET gate doesn't drift up into the linear region and induce the MOSFET to unsolder itself or otherwise do unpleasant and possibly smelly things.
Since most well-designed micro boards will have a supervisory circuit that floats the outputs or drives them low when the supply voltage is too low for normal operation, this also covers that pathological case.
Best regards, Spehro Pefhany
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