Thanks for your reply.
I am using Arduino Uno. I have a 12volt motor drawing 40 amps. I will use a relay like this.
http://www.kiatronics.com/kontiki-parts … 70405.html
I have a compass guidance system which is working ok. I want to set the time using a magnet utilizing hall effect or reed switches. The timer will need to be set in 5 minute increments up to 30 minutes and have a led light up for each increment then a separate switch to start the motor. Here is video of on working
https://www.youtube.com/watch?v=VMyf8yzgdHU.
I have some hall effect switches OH1881 which should work for the on off
Thanks again