I have recently bought the relay control PCB at http://www.sparkfun.com/commerce/produc … ts_id=9096 and all parts. I have followed the guide and soldered all components to the board including the 10k ohm resistor not included in the guide, but in the actual PCB drawing.
When I tried my board out, it didn’t work. I connect the relay board to my arduino duemilanove board with following:
Pin 6 (always on) to 5V
Pin 13 (blinking every 5 seconds) to CTRL
GND to GND
When my pin 13 is turning on, a very short blink (only a few ms) is visible on the control board LED. I do not hear click from the relay and no power is let through at the other side of the board.
leon_heller:
Have you tested the relay board on a 5V supply? It would be a lot safer to do that first.
Leon
Yes, I have tried it out at a power supply also with the 5V - same response. Only a very short blink when the CTRL turns on, and then it is out. If I cut the power to the CTRL line and attach it again, it will blink very shortly again.
The relay holds 4 pins. Two “big ones” and two “small ones”. I have tried to connect the 5V to one pin and GND to the other to see if anything happens (just very quick), but still no result.
Can it be the relay that doesn’t work? If it is, how is it possible that the led blinks shortly?
D1 wired backwards? That would cause a short and prevent the coil from being energized. I think the LED would exhibit similar behavior as the short would pull the +5V down.
Do you have DMM? I’d measure RAW to GND before and after JP2 pin 2 is pulled to +5. If the voltage drops then it’s probably a reversed diode. measuring resistance in-circuit won’t work. You could also hook up the DMM as an ammeter and measure the current though jp2 pin 3.
Philba:
D1 wired backwards? That would cause a short and prevent the coil from being energized. I think the LED would exhibit similar behavior as the short would pull the +5V down.
Do you have DMM? I’d measure RAW to GND before and after JP2 pin 2 is pulled to +5. If the voltage drops then it’s probably a reversed diode. measuring resistance in-circuit won’t work. You could also hook up the DMM as an ammeter and measure the current though jp2 pin 3.
It is not wired backwards. I have the 5V to 5V, GND to GND and 5V at on/off on CTRL. I know the led is correct, while the positive pin goes to directly in the 5V side and because there is a cutoff at the led and the PCB demonstrating how to put it in. I haven’t measured the volate in/out.
I was talking about the diode D1, not the LED or the board. If you inserted the diode backwards in the PCB, it would behave similarly to what you are seeing. It’s impossible to tell from your blurry pictures if the diode is in correctly.
Don’t use the arduino. Check to make sure there isn’t a short between power and gnd. Then wire up the relay board directly to power and use a short piece of wire to trigger the relay by bridging jp2 pins 2 and 3. If you have a switch, you could wire that into the terminals to make it easier. Then start measuring voltages. Watch out for shorts when you trigger the transistor/relay.
Reading the initial post, I see you were trying to power the board from a logic I/O on an Arduino. It would not be able to supply enough current, and you may have damaged the Arduino. The purpose of the transistor is to allow a logic level I/O to control the relay, with the relay board 5V terminal connected directly to a supply that can source more current. Connecting this terminal to an Arduino I/O shows a lack of understanding of the basic concepts involved. This may cause problems as other people in this forum try to solve your problem; there is a vocabulary gap. It may be a good idea for you to find someone local who has experience with electronics and can help diagnose the device and explain what the problem was.
That relay needs 200mA on the coil. You should be using an external power supply to run it as you are probably going to hit the USB current limit rather quickly.
To test it, get a 5V power supply (or for now, 3 1.5V batteries in series). Connect the positive to RAW and the negative to GND. Then take a jumper wire and connect CTRL to RAW too. The relay should turn on.
