Hello people!!!
I have a little problem with a external board that controls a dc motor speed and torque, you know varying voltage and amps... Well the thing is that the board has two pins to manually stop the motor by linking them with a wire.
Well, I would like to do that job automatically with my arduino, I've tried with a 5v relay, the coil side is connected to my arduino and the other two pins to my motor board stop pins, and well, nothing happens, I can hear the magnet crush when I do a pinout with my arduino so I thing the mechanism is working.
I also tried to solve the problem by connecting the wires to a 2n2222 transistor, controlling the base pin with my arduino, but again, nothing happened...
The pins to stop the motor have a little voltage (arround 0.5v) and I think that's the problem, I don't know too much about electronics so I would appreciate basic explanations.
Thanks in advance!
If a relay wil not stop it, and it will stop with a wire connected it looks like you have wired up the relay contacts wrong. I assume you either have a driver for that relay or it runs off less than 40mA. Also I hope there is a diode across that coil.
the board has two pins to manually stop the motor by linking them with a wire.
Does bridging the pins with a wire actually stop the motor ?
Grumpy_Mike:
If a relay wil not stop it, and it will stop with a wire connected it looks like you have wired up the relay contacts wrong. I assume you either have a driver for that relay or it runs off less than 40mA. Also I hope there is a diode across that coil.
Ah, a driver?? how's that, you mean a transistor and a external power supply?
This is my relay: http://www3.panasonic.biz/ac/e/search_num/index.jsp?c=detail&part_no=AJS1319F
And yes theres a diode, has been a loong time with this arduino, don't wanna loose it.
UKHeliBob:
Does bridging the pins with a wire actually stop the motor ?
Yes they do.
Have you connected the correct pins of the relay to your brake circuit?
You need to use the common (com) terminal, and then either the normally closed (n.c.) terminal if you want the brake to be on when the relay is not energise**d, or the normally open (n.o.) terminal if you want the brake to be on if the relay is energised.
If you have chosen to use the normally open and the normally closed contacts, then these never get connected together, and the brake circuit will not work.
JohnLincoln:
If you have chosen to use the normally open and the normally closed contacts, then these never get connected together, and the brake circuit will not work.
Hehe :-[ it was this, what a shame, the first time I use a relay, and I thoght the fifth pin was the normally open one not the common... Don't know why I didn't tested that before asking...
Thaks for you attention (:
Ah, a driver?? how's that, you mean a transistor and a external power supply?
That relay coil takes 72mA, this is nearly twice the current that causes damage on the Arduino pin, so yes a transistor. There is no need for an external supply, use the Arduino's 5V output.
legocris:
Don't know why I didn't tested that before asking...
But you do have a multimeter, don't you?