On a manufacturing floor I have a group of alarms hooked up to a kronos bell relay. The time clock that provided the scheduling and charge to fire this relay has broken and as a cost savings we are trying to use a raspberry to handle this process.
What I have done is wrote a simple python script that turns GPIO 17 on for 5 seconds and then turns it off. Using cron I have scheduled this and have it firing whenever I need the bells to ring. To test my logic I hooked a small LED light up to the PI and let it run for a day, the light blinked for 5 seconds as expected whenever cron called my script.
Today I went out to the factory and wired the pi into the bell relay and nothing happened, my thoughts were the GPIO was not providing enough output to fire the bell relay. As a test to prove this out I just hooked the 5V pin for power and the bell relay fired immediately. So I can make the bells ring when I hook directly to the 5v pin but the problem is then the bells will obviously ring forever.
So I guess at this point I am trying to figure out how can I use a GPIO pin to schedule the firing of the bells and yet provide enough power to fire the bells. If anyone has any ideas I would sure be happy to hear them.