HL-51 (3V relay)

Hi
I have a relay with the following specs
3~3.3V 1-Channel Relay interface board, and each one needs 15-20mA Driver Current
Equipped with high-current relay, AC250V 10A ; DC30V 10A
Standard interface that can be controlled directly by microcontroller ,such as Arduino , 8051, AVR, PIC, DSP, ARM and so on
Contact independent wiring, safe and reliable

I can't get it to work. I am actually wiring it to a raspberry pi (will try with arduino 3.3V later today). I am wondering if it should be powered by 5V and the signal is 3V. Is there a safe way to try it without frying the relay?

Below is a similar one.

http://sun-light.com.sg/index.php?route=product/product&product_id=3877

It should be powered form external 3.3V source. DOn't use 3.3V pin on Arduino since it can not provide enough current. Same could be true for PI but I'm not familiar with it.

And keep in mind - it's active low.

The RPi no different than the Arduino, max 3.3v output current is 50ma.

Rpi_Low-level_peripherals

150mA on the Arduino, not 50mA.

50mA is from when the FT232 was the 3.3V source.

CrossRoads:
150mA on the Arduino, not 50mA.

50mA is from when the FT232 was the 3.3V source.

Yes and the typical Songle 3V relay coil consumes 150ma.

Songle Datasheet

He'll fry the nano either way...

Thanks. That’s bad news. I was hoping to avoid putting an external power supply.

What are you attempting to control with the relay? You might be able to use a mosfet.

Another option might be a 5 volt relay but I’m unsure how tolerant the RPi is of a noisy relay switching on and off.

Edit: looks like it can be done, these are 5 volt coil relays.

Wow. That's cheap. I would be using it to control a gate arm. When the relay inputs are shorted, the gate opens.

If you think that's cheap . . . https://www.aliexpress.com/item/5V-16-Channel-Relay-Board-Module-Optocoupler-LED-for-Arduino-PiC-ARM-AVR/32834755914.html

I have this running off the same iPhone supply (5w) as feeds the 5v terminal on a nano.

The nano's 3.3v signals are enough to drive the otto-isolators.

Note that the single relay versions of the board seem to have no isolator, while the 2 to 16 relay versions do. I can drive that directly from an output pin.

I'm currently using 7, expect to use 4 more, and have a whole bunch of spares . . .

dochawk:
Note that the single relay versions of the board seem to have no isolator, while the 2 to 16 relay versions do.

2-8 channel relay boards with optos have optional opto isolation.
The 16-channel version has a serious design error.
Optos, but no opto isolation.
Leo..

I only need 1 relay (unless I somehow manage to fry them, then i'll use the rest of the 16 for spares :wink: )
I'll go to my local electronics store I hope I can find one with a built in opto-isolator and get this problem resolved.