ESPDuino: Dashboard relay widget partially activates relay

  • ESPDuino and YWrobot 4 channel relay

  • Dashboard through Web and Android

I can connect the ESPDuino to Cayenne with no issues. I’ve been partially successful with setting up the relay widget. I say partially as I can press the widget to turn on the relay, the relay board for relay 1 LED lights bright, I hear the click of the relay. However, when I turn off the relay through the dashbaord, the LED on the relay board doesn’t shut off, it goes dim or half brightness. The relay doesn’t click off.

The YWrobot relay board is a LOW on actuator, so when the 5v signal goes to ground, the relay actuates.

I’ve tested the relay with a normal Arduino and the relays work fine. However, when I rig it up to cayenne with the ESP, I get this odd result.


SOUNDS like TTL is 3.3V working with a relay that expects 5V. what is the GPIO output voltage for that device ?

The DOIT ESPduino is supposed to be a full 5v Arduino with an esp8266
built-in. The voltage is reduced onboard for the esp8266 chip only.

Here is a link to a photo.

unfortunately I didn’t find much discussion of the output voltage capabilities for your board, but as the 8266 runs on 3.3 V and I don’t see a significant 5 V regulator in that picture, I would have to guess you were getting 3.3 V.

there are two ways you can check this – put a voltmeter across the ground pin and any active GPIO port, you’ll see either 3.3 or 5 V

The alternative would be to take a known 5 V source, tie the ground to your relay board’s ground, and tie the positive to the VCC for the relay board as well as any one of the relay I/O pins. when you touch the 5v to that input pin, that relay should close fully.

The only other possibility I could think of is that whatever I/O pin you were using is being configured as an analog and is only being told to give 60% output. But that just sounds almost impossible, it sounds like your board is supplying 3.3 V when the relays expect five :slight_smile:

One quick check on either side of this equation and you’ll have a solid answer :wink:

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You were right, I’m getting 2.95v when the GPIO pin is activated. Odd though that the board ‘says’ it has both 5v and 3.3v outputs. I also realized I only have a 5v DC power supply and the board says it takes 6-16v for an input. Do you think my initial input voltage is too low for the board? I’ve added the link to the schematics at the bottom.

I swapped out my ESPDuino for a standard Arduino. That one is outputting 3.78v on the GPIO, and the relay is working just fine, full on/off.

Appreciate all of the support!

If the board calls for a 6v supply and you are giving it 5 that would explain why your output is 2,95v and not 3.3 like it should be. I doubt you will ever get 5v from your board as the ESP works at 3.3v.

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