waterpump

[fooa]

hey,

im thinking about a project which micropython would suit me well, besides the servos would it also be possible (and i guess so) to control a small water pump (just on off for a given timeframe) using the board? If so, which small pump would work and how to connect? Excuse me as im a total idiot when it comes to electronics but i prefer python for whatever other projects where i dont need to dig into this kind of stuff

[dhylands]

What size/voltage/current rating is the water pump?

Are we talking aquarium sized water pump here? Or well pump?

[fooa]

hey,

well, talking about mini pumps such as this one:

http://www.amazon.com/temperature-15GPH ... water+pump

[kfricke]

If you are just looking for cheap and easy to control water pumps, you should think about reusing a nice combo of some useful stuff like a solar powered water pump. Ebay has tons of them:
http://www.ebay.com/itm/Solar-Water-Pum ... 20c67ee4f6
Pros:

• Should easy be operated from battery power (e.g. 6V).
• Can be controlled by using cheap DC motor controllers (h-bridges like http://www.watterott.com/de/DRV8801-Sin ... er-Carrier).

Cons:

• These kind of pumps have a lower throughput of water.
• They do produce far less pressure than those industrial 12V+ pumps.
• These pumps might not be food safe in case you want to water your tomatoes, food safety should always be your primary objective!

[dhylands]

Ok - so thats a pump controlled by DC current.

You'll need a relay (mechanical or solid state) or a MOSFET which can be controlled by a 3.3v signal. You could also use a motor driver (more advanced, but fairly readily available).

By using a PWM signal, you can control the speed of DC motors using a MOSFET.

Here's an example of a MOSFET board that should suit your purposes:
https://www.sparkfun.com/products/11214

Pololu also carries several inexpensive motor drivers which would also suit your purpose:
http://www.pololu.com/product/2130
http://www.pololu.com/product/2135
http://www.pololu.com/product/713
(the ones above all work with 3.3v logic)

I've seen lots of 5v relays, but so far I haven't run across any 3.3v ones. You could control a 5v relay using a transistor or MOSFET, but the motor driver seems like the simpler solution to me.