I recently purchased a the Wireless Relay control mini Rboard and even though this is to be part of my first arduino project I mostly figured it out with the minimal documentation available. I am able to upload a sketch to it and got the wireless communication with a NRF24L01 board to work using the old bootloader for an ATmega 328p. The major problem I am having is getting the relay to turn on. Usually these opto-coupled relays need a LOW signal to turn on, but after looking at the schematic I see a transistor with a pull down resistor on the control lead which tells me that it needs a HIGH signal. The input to the transistor is labeled D4 so I assume that is the output pin I need to control. The program I uploaded using the foca interface and a TTL usb serial interface I purchased just for this board works fine according to the serial output, but will not turn on the relay. I got this setup working with 2 nanos and a relay on breadboards, but would like to be able to use this board after spending money on it and the usb interface. Also, it would have been nice if the board had a 3 terminal interface with the relay so I could use the NC pin on the relay also. I am using this for a wireless duct damper controller and need SPDT. I’ll just have to solder a wire on the bottom of the board instead. I appreciate any help I can get.
Hi @RRVogel and welcome to our forum!
Sorry for this late reply.
Have you bought these products from us?
Can we see your actual setup?
I purchased the Wireless relay mini Rboard from you. I’m not sure what you want to see, the board is a stand alone. I can paste the sketch here if you would like to see it. I have it working now with an Arduino transmitting to a nrf24l01 nano with a separate relay that uses a LOW signal for input, but the same sketch altered to send a HIGH to pin D4 does not engage the relay.
Order ID #998896. Product Code: RB-Ite-162.
Hi @RRVogel,
Did you maybe try applying voltage directly to relay’s coil to see if it is working or it is defective?
I wasn’t sure if I should do that as this is an optically isolated relay if it is like the one I have on a board for Arduino. I can give that a try I guess.
I had some time to test the board and I’m not sure what to do. I don’t have the board layout and can’t find a pin out for the relay online. I checked the voltage on the coil when the board is powered and it shows 5 volts at both coil terminals. I don’t know the internal circuit for the opto-isolated relay, which pin is positive and which is negative so I’m reluctant to try to energize the coil, not knowing the polarity. It would help if I could get a board layout or pin out for the relay. Online all the data sheets I could find did not label the coil plus or minus.
On further testing of the board, I’ve determined that the diode that is next to the relay is shorted which is probably causing the voltage to appear on both sides of the relay coil causing it not to function. I tested it in circuit to determine which side of the coil is positive and found that it is 77 ohms in both directions which means it is shorted. I don’t think I can replace it as it is a surface mount. I’m not sure what to do next. Please advise. I have uploaded an edited pic showing the diode:
Hi @RRVogel and thank you for testing all of this.
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