4 relay Arduino module control?

[BlackCorvette]

(4 relay module)

Is the Teensy 4.0 able to control one of these Auduino 4 relay modules ?

 

[kd5rxt-mark]

The I/O pins on the Teensy 4 are not 5VDC tolerant as inputs (3.3VDC max input level without causing damage), & only put out a nominal 3.3VDC as outputs. Most of the "Arduino compatible" relays require a 5VDC level signal to drive them, so you'll probably need something (external driver/adapter, transistor level-shifter, etc.) between the Teensy output pin & the relay control input.

Hope that helps . . .

Mark J Culross
KD5RXT

 

[jmarsh]

These relay boards nearly always use an opto-isolator to control the relay, they can work safely with a Teensy 4.x only if they have a separate logic VCC instead of connecting the opto-isolators directly to the same voltage supply as the relays.

 

[PaulStoffregen]

You won't be using Teensy pins in input mode with that relay board, so 5V tolerance of input mode isn't a factor.

What is a factor is whether that relay board can work with the 3.3V output signals Teensy transmits. It's difficult to give a 100% certain answer because that web page says to drive the control inputs with 5V and give it 5V power. It's utterly lacking in technical info like the specific optocouplers and resistors, so there's no way to tell for sure if driving the inputs with 3.3V instead of 5V will work.

But without specs or info, I'd guess the odds are pretty good. Almost all modern chips use 3.3V (or less) and most optocouplers have 1.3V forward drop LED input. Unless they used a higher resistor (that just barely lets the optocoupler work with 5V) your chances a pretty good.

When you buy that relay module, this question is really for the maker or seller of that relay board. Ask them if it works with 3.3V power and 3.3V signals. Or look for that info in the specs they give. Since almost all microcontrollers are now 3.3V, it's probably a common question already answered somewhere (just not on that tutorial page about old 5V Arduino boards).

 

[BlackCorvette]

The I/O pins on the Teensy 4 are not 5VDC tolerant as inputs (3.3VDC max input level without causing damage), & only put out a nominal 3.3VDC as outputs. Most of the "Arduino compatible" relays require a 5VDC level signal to drive them, so you'll probably need something (external driver/adapter, transistor level-shifter, etc.) between the Teensy output pin & the relay control input.

Hope that helps . . .

Mark J Culross
KD5RXT

Thanks. I believe the 3.3v output is where the problem lies since this is a 5v module.

 

[TFTLCDCyg]

I have a couple of these modules, identical to the one you mentioned. I'll use one of them to control the PWM fans; it's being tested.

The other has been running on a Teensy 4.1 board for over two years. It controls the PC's on/off switch, a servomotor that drives the PC's folding ventilation dome, a PWM fan, and a COB LED light for desktop lighting from the PC.

You must remove the JDVCC jumper with VCC. There, you power the board with the Teensy's 5V line on the JDVCC pin

On the other header: GND-IN1-IN2-IN3-IN4-VCC, you power it with 3.3V from the Teensy 4. This group is for the control logic.

This way, the 5V power supply will be used to operate the relays, and the 3.3V line will manage the triggering of each relay. I can assure you that what jmarisma points out is physically confirmed.

 

[jmarsh]

I can assure you that what jmarisma points out is physically confirmed.

Is that me?

 

[TFTLCDCyg]

Yep. Jejejeje translator errors!, I apologize for that

 

[BlackCorvette]

Thanks, I will set it up as you described..