First Arduino project.
Mung Bean sprouter.
I need heat control, pump control, and display drive.
I found what I think will be good for the Heat Controller and display driver.
https://circuits4you.com/2016/06/06/ard … ontroller/
Can I get that built with the program shown and then after that works,
go back and add additional code to start and stop a pump on a schedule?
Also, is it possible to set the pump schedule using the same switches
used to set temperature UP/DOWN set point?
Thanks, Mavam
That example looks like a good starting point; you might also need to use a voltage shifter between the different voltage systems (you mentioned 12v in the other post)
As I 'understand' The Uno has an onboard 5V regulator and you can power it with 12V. My relays have 12V coils and my heaters are 12 V. So, my plan is to use a 12V power supply. Using an NPN transistor as switch with a grounded emitter, I expect 5v is more than enough to turn on the transistor with the load on the collector and 12V on the load. So, I'm not sure where I need a level shifter??TS-Russell:
That example looks like a good starting point; you might also need to use a voltage shifter between the different voltage systems (you mentioned 12v in the other post)
After this works,
Can I go back and add more code to operate the pump on a schedule.
Also can I use the same switches that setup for the Temp adjustment for the pump scheduling adjustment?
Mavam.
Sure; it just depends on how you’re implementing it…‘many ways to skin a cat’ (you know the ratings of your relays & whatnot, which communication protocol will be used, etc) - so you might need them (but it sounds like you don’t) 
I expect 5v is more than enough to turn on the transistor
A suitable base resistor is required for the NPN transistor, and the transistor must be able to easily handle at least 2X the heater current.
For a non-Darlington NPN transistor, the base resistor should be chosen to limit the base current to 1/10 or 1/20th of the heater current.