I need help developing / manufacturing a 12v dc timer
I am not a electronics expert, but I have tried to list details below:

12v power in (line in power protection as voltage may drop when starting the engine)

12v 5+ amp output

Button switch / magnet switch / light sensor to set mode

Mode 1 = 5 minutes off 23hr 55min

Mode 2 = 10 Minutes off 23hr 50 minutes

Mode 3 = 15 minutes off 23hr 45 minutes

Led blinks after mode set - shows current mode

This timer will be used to power a small water pump connected to a starting battery on a boat

I would like this to be as small as reasonable

Timer starts in mode 1 (or previous mode) when unit is powered on (if disconnected or power is lost)

Contact me with any information / suggestions

 

A micro-controller with a 32.768 Khz watch crystal.

Define the behavior a bit more- what happens after it turns on?

Is the pump drawing 5A continuous, or is that the start-up current?

 

pump turns on for selected duration and then turns off - cycle repeated every 24 hrs

yes, 5a continuous - a higher amp rating would be a welcome feature in the event we must change the model of the pump
pump that we are looking at is 2.4 amp continous with a peak load of 3a

 

Probably easier to get a Ready-made one like these...

https://www.ebay.co.uk/itm/DC-12V-D...331606834231?_trksid=p2385738.m4383.l4275.c10

 

Doggydave, Thank you for your suggestion. I started with one of these for early testing. The final product I am hoping to keep simple for the end user and be much smaller.