Are Raspberry Pi 4 GPIO pins sufficient for motor, pump, and sensor control?

[remzirecep]

Hello,

I’m using a Raspberry Pi 4 Model B and I need to perform the following tasks for a project:

I will control a motor or a water pump, which may be 220V AC, 12V DC, or 24V DC (I haven’t decided yet). I’m looking for a safe control module that would be compatible with all three cases (e.g., a relay module or motor driver).

I also need to read data from both digital and analog sensors through GPIO,

And send output signals via GPIO pins.

So my main question is:
Are the built-in GPIO pins on the Raspberry Pi sufficient for this kind of setup, or do I need additional modules (such as an ADC converter, GPIO expander, or motor/pump control board)?

As far as I know, the Raspberry Pi doesn’t have native analog input, so I may need an ADC. If you can recommend reliable or commonly used modules for these tasks, I’d appreciate it.

I’m planning to use basic sensors like temperature, humidity, or pressure sensors, though I haven’t finalized the components yet.

Thanks in advance!

[DougieLawson]

• Anything that needs high voltage needs a transistor, an optoisolator or a relay between your RPi and the load.
• Anything that is more than 3.3V needs a transistor between your RPi and the load to protect the RPi.
• You can't switch any AC directly, it needs a relay or an optoisolator.
• Anything that has AC mains electricity needs a relay between your RPi and the load and needs careful protection between you and the mains (as it can kill). If you don't understand mains don't work with mains. The relay may need a transistor between the RPi and the load for the above reasons.

[remzirecep]

• Anything that needs high voltage needs a transistor between your RPi and the load.
• Anything that is more than 3.3V needs a transistor between your RPi and the load to protect the RPi.
• You can't switch any AC directly, it needs a relay or an optoisolator.
• Anything that has AC mains electricity needs a relay between your RPi and the load and needs careful protection between you and the mains (as it can kill). If you don't understand mains don't work with mains. The relay may need a transistor between the RPi and the load for the above reasons.

Thank you for your response.

I'm aware that I need to use a transistor for triggering and a relay to handle power to the load. However, since I'm currently in the testing and prototyping stage, I'm looking for a ready-made module that already includes these functionalities.

Could you recommend a safe and Raspberry Pi–compatible relay or driver module that would be suitable for this purpose?

[DougieLawson]

What voltages are you talking about?
3.3V?
5.0V
SELV (safe electrical low voltage) that's less than 48V?
mains?
AC or DC?

[gordon77]

To keep it simple and safe...

If using 24v or 48v try a relay hat eg. PiRelay 6 - The Pi Hut https://share.google/TI0Z8symElytIgTLM

( Although it says it will switch 240v l wouldn't put 240v through a pcb card)

For 240v try something like this https://www.raspberrypi.com/news/contro ... berry%20Pi.

[remzirecep]

Thank you for your responses.

I will only use the Raspberry Pi to send control signals to the relay. I would like to decide myself whether to apply DC or AC voltage to the COM pin of the relay.

Additionally, I want to measure temperature, read the state of a switch, and get data from a gas sensor. Do you have any suggestions for these types of sensors?

If possible, I would prefer to connect them directly to the Raspberry Pi GPIO pins. But if that’s not suitable, could you recommend a proper module?

Also, if there are any example videos or projects related to this topic, could you please share them with me?

[jamesh]

Thank you for your responses.

I will only use the Raspberry Pi to send control signals to the relay. I would like to decide myself whether to apply DC or AC voltage to the COM pin of the relay.

Additionally, I want to measure temperature, read the state of a switch, and get data from a gas sensor. Do you have any suggestions for these types of sensors?

If possible, I would prefer to connect them directly to the Raspberry Pi GPIO pins. But if that’s not suitable, could you recommend a proper module?

Also, if there are any example videos or projects related to this topic, could you please share them with me?

Temperature is easy; almost any I2C based sensor will work. GPIO switching, also easy, a direct connection to the GPIO. The gas sensor will depend on the sensor; an I2C one is probably easiest. You can probably find an I2C device with both gas and temperature sensing (what sort of gas?).

There are any number of videos and websites covering all this out there.

What is the use case? It might be easier to recommend stuff with a bit more insight into what you are doing.

[ghp]

For switching 240 V devices I would look for something like "Shelly Pro 1". Or perhaps a relay module with modbus control.

https://www.shelly.com/de/products/shelly-pro-1
https://www.waveshare.com/product/modul ... ay-4ch.htm

basic sensors like temperature, humidity, or pressure sensors

There are all flavors of these sensors available which already have a digital interface.
Example BME280 breakout https://www.adafruit.com/product/2652

If distance from sensor to RPi is larger than 0.5m, then it is getting more complicate to connect to the sensors. I have a temp sensor prox 100km away. A simple wire will not work in this case.

[remzirecep]

Thank you all for your helpful responses. Let me explain in more detail:

I want to measure the temperature of a liquid using one temperature sensor, and the ambient temperature inside the cabinet using another. Additionally, I’d like to monitor the gas concentration inside the cabinet with a gas sensor. I plan to use a water pump to circulate the liquid, and when the gas concentration exceeds a certain threshold, I want to activate a fan to ventilate the cabinet. To monitor the liquid level, I will use switches to detect the maximum and minimum levels.

If you have any suggestions for modules or electronic components that could help me implement these functions, I’d really appreciate it.

[jamesh]

All of that could be done on a Pico or Pico 2 - and it would probably be easier to implement on those than a full grown Pi SBC. It will depend on what other features you need, for example , user interfaces. You just need to add the appropriate sensors and switches.

https://www.raspberrypi.com/products/ra ... pi-pico-2/

[remzirecep]

All of that could be done on a Pico or Pico 2 - and it would probably be easier to implement on those than a full grown Pi SBC. It will depend on what other features you need, for example , user interfaces. You just need to add the appropriate sensors and switches.

https://www.raspberrypi.com/products/ra ... pi-pico-2/

Thank you for your response.

Since I plan to include a user interface and want the system to run more smoothly, I’ve decided to use a Raspberry Pi 4. I’m looking for modules that I can connect via the GPIO pins. I will control the pump and the fan using a relay module. Additionally, I need suitable modules for measuring temperature, gas concentration, and liquid level.

Could you please recommend a relay module, temperature sensor, gas sensor, and liquid level sensor that are fully compatible with Raspberry Pi 4 Model B? I would also appreciate any advice regarding the electrical connections or circuit considerations.

[remzirecep]

Is the circuit diagram in the photo I sent appropriate? Will it damage the Raspberry?

[remzirecep]

Help please!

[gordon77]

That relay should work but use high trigger.

Don't put the link to low trigger !!

[ame]

Help please!

I posted about this specific relay module a number of times, including here: viewtopic.php?t=371606#p2225736

[ghp]

The schema drawn for the relay board is not correct. The connection EL354 collector to 2N5401 emitter will force the transistor always off.