Alternativs for using relays as outputs (Bounce problem) ???

Hi all

Im using an UNO and the Relayboard shield with it and i have a problem When activating my program its suppsed to active relay 1 for 40ms, delay 20ms, activate relay2 for 20ms wait 20 ms and relay 3 for 20 ms and wait 20ms.

Its working good in 9 times about 10, but the machine i controll with the relay pulses are locked up at 9 o 10 times of the pulses and i think it has something about bounce in the relay contacs, the realys uses the - 12 V from the feeding power to the UNO from the NO contacs to the machine.

What i understand i cant get any output pins to go negative, any ides to skip the relays and maybe use a transitor to get a fast negative controlled pulse out?

Best Regards



need to know if it is AC or DC, what voltage and also amps.

also, what are you controlling ? a motor ? solenoid ?

also, you state you cannot get the pins to go negative. do you have a negative power rail available ?

The three relays are emulating a coin drop on a IGT slot machine, the first pulse is the ok signal for coin thrue coin mec, the 2 and 3 pulses are from two optos that the coin going thrue The machine is getting 3 negative pulses from my relays to the IGT computer, if there is bounce from the relays the slotmachine thinks there is a failure/fooling and stopping the machine.

Best regars


We are looking more for voltages, actual device is not required.

We can assume that the coins pass through opto-interrupters.

if you have access to the sensor, you could set up a means to actually interrupt the sensor. a stepper and a slotted disk for example.

Assuming (again) that the opto-interrupters are board voltage of 5 volts DC, then you can use a transistor. I am not sure what the negative pulse is. pulling to ground ? suppling a negative voltage ?

A wiring diagram would help more than anything.