Flip clock – one minute impulse 24vdc (+ and - in turns)

I found a good looking Twemco flip clock. Unfortunately the unit is only a slave without control unit. The unit works with some type of two position “step motor”. If you supply the unit with +24vdc impulse, the minute changes. Then you need to supply -24vdc impulse to get the next minute. And then again +24vdc… I tested this manually with power supply and the clock works perfectly.

I read the instructions on http://arduino-info.wikispaces.com/ArduinoPower. Based on examples on that page I think my project can be solved with Arduino, relay and 24vdc power supply. Am I right? And an open issue is how to make the – and + change, do I need two relays (one supplying – every two minutes and other supplying + every two minutes?)

I would appreciate if somebody could guide me how to approach this project.
Thanks,
Miika

You would need two relays or a motor control "H bridge" shield. I would prefer to use the motor controller but you should use whatever is easiest for you.

Using two relays, you need to wire one rela(A) to reverse the voltage when active. The other relay(B) then turns on the voltage.

First minute turn on B
Second minute turn on A then B then A off
Repeat.

Using a motor shield is easier as you simple reverse the drive each minute.

Weedpharma

IMO a pulse is sufficient, no need to apply the voltage all the time.
If you want to use a relay, take a DPDT one.

I meant pulse (forgot I was talking to non experienced member).

Weedpharma