
Doombot
USA
Asked
— Edited

Hey guys, what's the best and safest way to trigger 12V Relays from the Digital pins? Thanks.
I tried a Tip120 Circuit with a 1K resistor, didnt work, then with a 2.2K resistor, didn't work. I have an LED hooked up to the digital pin so I know it works, the LED lights up.
4 Channel 12V Relay Module Board Optocoupler LM2576 Power Supply Arduino
With one of these.
Logic Level Converter 3.3V to 5V TTL Level Converter Logic Bidirectional
Both available on EBAY for cheap...Datasheets available online.
Here's what I used:
I changed the shorted out B1 and B2 to four separate digital pins. Here's what I did:
What do you guys think? Am I gonna be able to apply PWM to this or no dice?
P.S. I'm using this setup for the shoulder motors, not for the drivetrain. I'm using a 300A electronic speed controller for that.
For Arduino VNH2SP30 Stepper Motor Driver Module 30A Moto Shield Replace L298N
It cost less than $14.00 same one that Sparkfun sells for $70.00
And yes you should be able to use pwm for control of your circuit.
Likewise a 1 1 (on B1 and B2) of the first cct will also cause much smoke, its easy to accidentally do this with a simple coding error, the invertor method averts this.
Tony
I'm pondering your advice and I don't understand how these would smoke, I have tried this on relays triggered with manual switches in place of the Tip120's.
I'm not very experienced at how Transistors work. Please elaborate.*confused*
Here:
How is it shorting out? Switching D0 and D3 closes the forward circuit and switching D1 and D2 should close the reverse circuit. Of course I won't switch everything on and assume it's "brake".
This is not going to be for continuous rotation, I'm only using this for short spurts since I'm using these motors for the shoulders.
*tired*
Oh, I think I understand your post now. Thanks.
Tony
Tony