Raspberry Pi Forum - Recent Threads

Is it possible to read simultaneously from same sensor with python raspberry pi

Kenne76 — Tue, 21 Jul 2026 09:21:19 GMT

Is it possible to read simultaneously (to two variables) from same sensor with python raspberry pi?

RE: Is it possible to read simultaneously from same sensor with python raspberry pi

dougw — Tue, 21 Jul 2026 21:20:17 GMT

RPi is a sequential machine. How much time do you have to copy to 2 variables and still call it simultaneous?

RE: Is it possible to read simultaneously from same sensor with python raspberry pi

Jan Cumps — Tue, 21 Jul 2026 09:39:35 GMT

Do you have info about the sensor, and what protocol needs to be used to read its data?

(and what is your definition of simultaneously? Is there any time allowed between the reads?)

RE: Pi 5 Custom Active Fan setup

ralphjy — Tue, 30 Jun 2026 05:23:31 GMT

You might try looking at this link how-to-customize-raspberry-pi-5-fan-speeds.

Here is the relevant info from that discussion:

"You are correct that the device-tree is where this is configured, but the dtb file is the compiled device-tree which isn’t (directly) editable. However, in this case we don’t even need to edit the device-tree itself because the values you want to tweak are parameterized and can be customized simply by adding some lines to /boot/firmware/config.txt.

Firstly, the reference file you want to have a look at is /boot/firmware/overlays/README. This text file documents all the available device-tree overlays, and their parameters. It also documents the parameters for the base device tree, which is what we’re interested in here.

Search for fan_temp0 in that README file and you should find yourself at the start of the various fan-related parameters in the base device-tree. I’ll quote them here, but you should double-check in that file in case they’ve changed across kernel versions:"

***********

fan_temp0 Temperature threshold (in millicelcius) for 1st cooling level (default 50000). Pi5 only.
fan_temp0_hyst Temperature hysteresis (in millicelcius) for 1st cooling level (default 5000). Pi5 only.
fan_temp0_speed Fan PWM setting for 1st cooling level (0-255, default 75). Pi5 only.

fan_temp1 Temperature threshold (in millicelcius) for 2nd cooling level (default 60000). Pi5 only.
fan_temp1_hyst Temperature hysteresis (in millicelcius) for 2nd cooling level (default 5000). Pi5 only.
fan_temp1_speed Fan PWM setting for 2nd cooling level (0-255, default 125). Pi5 only.

fan_temp2 Temperature threshold (in millicelcius) for 3rd cooling level (default 67500). Pi5 only.
fan_temp2_hyst Temperature hysteresis (in millicelcius) for 3rd cooling level (default 5000). Pi5 only.
fan_temp2_speed Fan PWM setting for 3rd cooling level (0-255, default 175). Pi5 only.

fan_temp3 Temperature threshold (in millicelcius) for 4th cooling level (default 75000). Pi5 only.
fan_temp3_hyst Temperature hysteresis (in millicelcius) for 4th cooling level (default 5000). Pi5 only.
fan_temp3_speed Fan PWM setting for 4th cooling level (0-255, default 250). Pi5 only.

The syntax for customizing these is a little strange, but not too difficult. In /boot/firmware/config.txt you need to add lines with the format dtparam=PARAM=VALUE. For example, if you want to change the base temperature at which the fan turns on from 50°C to 55°C you might append the following (bearing in mind the value is in millicelcius):

dtparam=fan_temp0=55000

You can list multiple parameters in a single dtparam= line like so:

dtparam=fan_temp0=55000,fan_temp0_speed=90

Alternatively, you can use multiple dtparam= lines, if you prefer:

dtparam=fan_temp0=55000
dtparam=fan_temp0_speed=90

***********

Pi 5 Custom Active Fan setup

brex2048 — Mon, 29 Jun 2026 20:33:19 GMT

I am trying to setup a custom fan setting so that it will come on sooner, just to help keep it cooler. I have found the config.txt, how do I actually set a custom fan profile. The file is blank right now.

IA Generador neural network library for microcontroller

rbasulto53 — Sat, 13 Jun 2026 23:53:01 GMT

Hello, please let me know what you think of this AI web application for improvement. It allows you to generate trained neural network models for use with microcontrollers like Raspberry Pi Pico, ESP32, etc. These models don't require an internet connection and are trained by loading a CSV file. It dynamically maps inputs and outputs and has two hidden layers whose architecture can be configured.

The link is:

https://traindeep.ai

thanks

RE: IA Generador neural network library for microcontroller

rbasulto53 — Thu, 25 Jun 2026 00:49:32 GMT

hi,
We ran tests on the rp2040 and obtained these measurements (execution time of already trained model)
- 3 inputs, 2 hidden layers, and 6 neurons per layer with ReLU activation function: 3.5 ms
- 3 inputs, 4 hidden layers, and 10 neurons per layer with ReLU and Leaky activation function: 7.1 ms

RE: IA Generador neural network library for microcontroller

rbasulto53 — Wed, 24 Jun 2026 14:52:20 GMT

Ready version 2.0.
https://traindeep.ai

RE: IA Generador neural network library for microcontroller

rbasulto53 — Wed, 24 Jun 2026 14:50:55 GMT

thanks for you comment. Please check out the new version 2.0. It has much of what you mentioned and much more.
https://traindeep.ai

RE: IA Generador neural network library for microcontroller

DAB — Tue, 16 Jun 2026 20:34:11 GMT

If you want anyone to bother with your link, you should greatly expand your description of what is at the end of the link.

It generates a trained NN. So what?

Give me a useful example so I can be intrigued about the possibilities.

Provide a walk through of the process so I can see how easy it is to use.

What is the size of the resulting output? How useful is it? How limited is its application?

You have to make a reasonable effort to sell it if you want anyone to kick the tires.

RE: IA Generador neural network library for microcontroller

rbasulto53 — Mon, 15 Jun 2026 14:19:42 GMT

Thank you very much for your comment. Yes, I will be running performance tests, although the generated library is very lightweight for high performance and low resource consumption.
Another important difference is that it doesn't require installing anything to create the model, as it's trained on the web, and you don't need any libraries to run the trained model; it's very simple.

RE: IA Generador neural network library for microcontroller

Qbit — Mon, 15 Jun 2026 11:46:12 GMT

This is a really interesting project! I've been exploring the challenges of running neural networks on microcontrollers myself. Have you had a chance to compare the performance of IA Generador against other lightweight libraries like emlearn or NNoM? I'd be particularly interested in seeing a benchmark for inference speed on a Raspberry Pi Pico or an STM32 board. I'm excited to see where this project goes. Keep up the great work!

RE: IA Generador neural network library for microcontroller

rbasulto53 — Sat, 13 Jun 2026 23:34:20 GMT

Thanks for the welcome, this application is to help the community and has no commercial purpose.

RE: IA Generador neural network library for microcontroller

colporteur — Sat, 13 Jun 2026 22:56:01 GMT

What would be my motivation, to have me click on a link, from a user with a profile of 25 points.

That score would suggest you are new to the E14 community. Welcome.

RE: Raspberry Pi 4 GPIO Leakage Voltage (1.2V) When LOW on Relay Module

geralds — Thu, 04 Jun 2026 20:44:32 GMT

[quote userid="522264" url="~/products/raspberry-pi/f/forum/57009/raspberry-pi-4-gpio-leakage-voltage-1-2v-when-low-on-relay-module"]

Wenn der GPIO-Pin HOCH ist, messe ich genau 3,3 V auf der Leitung, was korrekt ist.

Wenn der GPIO-Pin auf LOW statt 0V eingestellt ist, sehe ich eine konstante 1,2V-Leck-/Schwimmenspannung am Multimeter.

[/quote]

Look here: https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#gpio-pads-control

most of the port pin are tri-stated pins.

Yes, it means that the pin can have 1.2V - the middle of the supply voltage as well as meaning this state is in "high-Z".

This is NOT a "leakage". 😉

Z = Impedance in (k)Ohm.

This function is a very important function if you want to use that pins with different jobs.

Such port can be driven in: "switched on" (sending high to the output), "h-Z" (the software let the port "swimming"), "switched-off (sending low to the output)

Gerald
---

Raspberry Pi 4 GPIO Leakage Voltage (1.2V) When LOW on Relay Module

emreeyy — Wed, 03 Jun 2026 20:33:00 GMT

Hi everyone,

I am using a Raspberry Pi 4 Model B to control industrial 24V relay modules. However, I am not using an external 24V power supply; instead, I am routing the Pi's own 3.3V pin to the common power rail of the relays to use them as simple mechanical switches for 3.3V signals.

I have wired the Raspberry Pi GPIO pins directly to the relay signal inputs via a simple terminal block breakout board (no transistors or optocouplers are used yet).

The Problem:

When the GPIO pin is ⁠HIGH⁠, I read exactly 3.3V on the line, which is correct.

When the GPIO pin is set to ⁠LOW⁠, instead of 0V, I see a constant 1.2V leakage/floating voltage on the multimeter.

There is currently no common ground (GND) connection between the Raspberry Pi and the panel's internal structure. I suspect this 1.2V is due to a floating ground issue or feedback leakage through the relay's internal coil/status LED.

What is the best way to eliminate this 1.2V leakage and get a clean 0V when the pin is LOW? Should I use an optocoupler module (like PC817) or a transistor driver?

Thanks in advance!

RE: Raspberry Pi 4 GPIO Leakage Voltage (1.2V) When LOW on Relay Module

DAB — Thu, 04 Jun 2026 19:53:31 GMT

The RPI does some interesting things with the GPIO pins.

You may have to set up some external termination resistors to get the right behavior.

As I recall, there are some internal options you can set to the output configuration to use internal termination.

RE: Raspberry Pi 4 GPIO Leakage Voltage (1.2V) When LOW on Relay Module

robogary — Thu, 04 Jun 2026 19:22:43 GMT

Hi emreey.y.

Please reference my spring clean 2026 project: The WrongCo Garden Guardian (a.k.a. Rube Frankenstein).

I have schematics showing a raspberry pi pico 3v outputs driving 3v relay modules and 3v mosfet boards. The modules then drive 12v circuits. These output driver boards could just as easy pilot 24v devices.

RE: Raspberry Pi 4 GPIO Leakage Voltage (1.2V) When LOW on Relay Module

dougw — Thu, 04 Jun 2026 14:22:19 GMT

You need to supply a schematic of the connections. Typically a Pi output pin cannot drive a relay coil because the voltage is too high, the current is too high and the inductive flyback is too high. It sounds like you are trying to pull down a coil pin of a coil whose other pin is connected to 3.3V. The I/O pin cannot sink enough current to pull that pin to ground. A transistor would help, but the coil may need a higher voltage and it would definitely need a snubber diode.

RE: Raspberry Pi 4 GPIO Leakage Voltage (1.2V) When LOW on Relay Module

geralds — Wed, 03 Jun 2026 23:47:11 GMT

Hello,

1. Do NOT connect a 24V relay directly to an output of the Raspberry Pi. This will damage the Pi's port.

2. You need an external driver transistor to control the 24V relay. Alternatively, you can use an optocoupler such as the PC817.

The GND - normally - is the base of each switched schematic, special circuits can have other base voltages.

A relay has three operating states:

a) Turn-on voltage: This is the minimum voltage at which the relay turns on.

b) Hold voltage: This voltage is slightly lower than the turn-on voltage and can be even lower before the relay turns off. This voltage can help save power.

c) Turn-off voltage: This voltage is so low that the relay turns off. A voltage may still be applied, but it will no longer be held.

You can find the voltage states of your 24V relay in its datasheet.

3. You can use an NPN transistor, for example. BC547 or BC546 or similar switching transistors (emitter to GND, collector to the relay) – the relay is connected to the supply voltage (+24 V).

4. Don't forget the diode, e.g., 1N4007, in parallel with the relay coil; cathode to the positive supply voltage, anode to the switching transistor collector.

Alternatively:

There is another option where the relay is connected to ground (GND) and can be switched with a PNP transistor.

However, this circuit is somewhat more complex and requires a few more components.

RE: Raspberry Pi 4 GPIO Leakage Voltage (1.2V) When LOW on Relay Module

colporteur — Wed, 03 Jun 2026 22:55:14 GMT

If the Pi is going to power and external device they both have to have a common ground reference. 3.3V on the Pi is referenced to its own ground. If the Pi's ground is not the same as the equipment ground, you will have issues. Let's just say I have had issues until I create the common ground.

RE: Raspberry Pi 4 GPIO Leakage Voltage (1.2V) When LOW on Relay Module

robogary — Wed, 03 Jun 2026 22:21:06 GMT

reference the rpi common to the panel internal structures common and the rpi power input common. Make everyone's common , in common.

RE: Raspberry Pi 4 GPIO Leakage Voltage (1.2V) When LOW on Relay Module

shabaz — Wed, 03 Jun 2026 21:34:39 GMT

Hi,

You may need to sketch a diagram, and attach a photo showing your setup, and links to the relay module and any other bits you're using. Right now it's very unclear what your precise set-up is.

MoOde audio and Raspberry Pi 5

Mark87 — Sun, 17 May 2026 00:32:26 GMT

Hi there!

I’m experiencing the same issues with moOde Audio performance when using the built‑in Wi‑Fi server. The problem occurs very frequently—after about two months of running optimally, the system starts freezing repeatedly. When this happens, I can’t stop playback or perform any other actions.

My setup is a Raspberry Pi 5 (8GB) running moOde Audio Player 10.2.0 (64-bit Trixie) and a official power supply For a Raspberry Pi 5 .

Any suggestion about how overcome this issue?

I wrote a handson Raspberry Pi Pico 2 project book free review copies for embedded devs

micheal.embedded — Mon, 29 Dec 2025 12:24:46 GMT

Hi everyone, I’m Michael Bell I write embedded systems books for beginners and professionals.
I just released “Embedded Systems with Raspberry Pi Pico 2 and RP2350: Projects and Deep Dives”.
This is a project-based book that takes you from blinking LEDs to building real embedded systems using the RP2350, GPIO, timers, interrupts, and communication interfaces.
I’m looking for honest feedback from developers and hobbyists.
If you’re interested, I can send you a free Kindle copy in exchange for an honest review on Amazon. No pressure I just want to make sure the book is practical and useful.
You can also check out the example code and projects on GitHub here:
[emoticon:bff6f573746e4db3bab4385412e5dd76] github.com/.../pico-embedded-book
And here’s the Amazon page to see the book details:
[emoticon:bff6f573746e4db3bab4385412e5dd76] www.amazon.com/.../B0G62PXWTP
Many of the projects include detailed walk-throughs and debugging notes so you can learn how and why things work.
Thanks for helping me make embedded learning better!