Where can I get a cheap "precision" timer relay?

I'm building a machine (programmable fish feeder) that needs a relay open and closed according to a program. I would prefer a programmable timer with 7-day 365 functionality similar to a programmable thermostat. I have found timer relays of this sort (such as Altronix 724 timer board) but none I have found... show more I'm building a machine (programmable fish feeder) that needs a relay open and closed according to a program. I would prefer a programmable timer with 7-day 365 functionality similar to a programmable thermostat. I have found timer relays of this sort (such as Altronix 724 timer board) but none I have found can control in the seconds range. I would need to open and close relays for anywhere between 0 and 90 seconds. Industrial timers from Omron and others don't have the functionality I'm looking for and are expensive. I would be open to schematics on how to build one if it could be done cheaply. Any suggestions?

Needs to operate on 12VDC and relay contacts should be at least 10A but that's fudgeable using another automotive relay for current capacity. Could possibly modify an alarm clock?
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