12 Vdc water pump controler-advice needed

geologeek

Hi there,

I am looking to use my stamp if possible to control a water pump.

What i need is to be able to adjust its on/off sequence from just under a second up to 10 seconds or there abouts - this is easy enough i think to sort out but the problem is i need to have it running full at 12v when on and down to 4ish volts when "off"

Any pointers please as i am sure you clever guys and galls can figure this out!

List of parts would be helpful also! i have the stamp and a collections of bits, power packs, solid state relays!

All i need is a clue

pgamblin

There are a number of ways to accomplish this task. Not knowing what your background is, I would suggest using a Crydom solid state relay. It can be driven directly by a Stamp via a 120 ohm resistor. a conventional relay would probably be cheaper and you would need to use a driver transistor. You will need to make sure that whatever device you choose can handle the current demands of your application. The code should be fairly straight forward. Lowering the voltage to the 4 volt level may damage the motor. A 12 volt motor wants 12 volts or nothing.

geologeek

thanks,

it good when someone puts a bit of common sense into the equation!

I am looking to control a powerhead and was concerned that just switching on and off would damage the pump!

the idea is for a wave maker for my fishtank and was thinking of a digital potentiometer to control a transistor with 12v running through the C and E.

The thinking was to have the pump on full tilt (12v) for a second and reducing in speed to about the 4v to keep the propeller ticking over for a second............to get a backwards and forwards swell going!

It never occurred to me though that the pump wouldnt work with less than 12 volts!

cheers,

levi