Questions tagged [raspberry-pi]

The Raspberry Pi is a credit-card sized computer that plugs into your TV and a keyboard. There have been several generations of the device with improved performance, more memory, and more connectivity. This tag should be used for electrical engineering questions that involve the use of a Raspberry Pi. For questions about the Raspberry Pi itself see the raspberrypi.stackexchange.com Raspberry Pi specific forum.

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3 answers
721 views

Power-Supply "Combination": Solar for voltage + Battery for current

I'm rather new to circuits & DIY electronics, but am thoroughly enjoying tinkering with my new RaspberryPi and assorted components. I'm trying to power the device using a few simple solar panels I ...
1 vote
1 answer
490 views

Trying to control vintage amplifier (TEAC A-H500) with Raspberry Pi - what's the communication protocol? 8-bit bus?

I'm trying to control my vintage amplifier from Raspberry Pi - I want to create a nice little Spotify streamer that on playback start will automatically turn on the amplifier and set the input ...
2 votes
0 answers
58 views

Logging data from High Precision AD/DA board using Raspberry Pi 3B

I have a High Precision AD/DA board from waveshare with Raspberry Pi 3B (running on Raspbian). However, I can write only 27 samples in 1s in my CSV file. I am using this Python code for writing to a ...
2 votes
1 answer
430 views

Daisy-chaining two ADC with SPI protocol

I'm trying to configure and read two ADCs (MAX11156) with a RaspberryPi. The ADCs are daisy-chained together. For the communication, I'm using python code with the spidev library. The driver is ...
0 votes
1 answer
59 views

Switch power to load using 2 GPIO pins, 5V and 12V

I will like to use 2 GPIOs on a raspberry pi to switch on a device (piezo buzzer), using 5V or 12V at a time. My idea is to use two MOSFETs and place pullup resistors on the gates of the MOSFETs from ...
-4 votes
0 answers
27 views

Is this 5V-UPS circuit useful? [duplicate]

I have attached a picture of a circuit for my UPS: My goal is to supply my Raspberry Pi a few seconds longer after power failure. VCC = 24V, +5V = regular 5V supply voltage via LM2596. UPS = 5V ...
1 vote
2 answers
612 views

ESP32 UART to Raspberry Pi I2C

I am trying to understand how to connect an ESP32's UART pins to my raspberry pi 3B+'s I2C pins. I see several bridge chips available for this like TI's MSP430 Datasheet. But I am not very circuit ...
4 votes
0 answers
79 views

Can this Raspberry Pi UPS circuit work?

I created following UPS circuit to shutdown my Raspberry Pi 3A+ properly: I would really appreciate if somebody can review my circuit. I know it's a little bit hard to read, but I'm sorry. I'm a ...
0 votes
1 answer
156 views

How to receive input signal on Raspberry pi GPIO from transistor emitter

I'm trying to build a simple circuit that allows a Raspberry Pi to detect AC voltage in piece of wire inductively. I have the following circuit which basically uses an antenna wrapped around the wire ...
0 votes
1 answer
34 views

Can't drive stepper motor (42BYG) with a Raspberry Pi

The end goal is to make a chess board that moves the pieces by itself with help of a plotter. We already got most of the software. We only need to make the plotter work but we are having trouble with ...
2 votes
5 answers
6k views

How to control a motor driver (BTS7960) without PWM

Using a Raspberry Pi 3B+, I need to control a motor which works in 12V and can draw up to 2A. It doesn't use PWM. It just goes in one direction or the other (reverse/forward) when interchanging the +/-...
0 votes
0 answers
33 views

Any Hirose DF40C ribbon cables out there? [closed]

I am currently working on a project with compute module 4 from raspberry pi foundation. It is supposed to be very compact so I bought one of the smallest IO boards that I could find. Everything works ...
0 votes
1 answer
325 views

Raspberry Pi hat design

I am designing a Raspberry Pi hat that needs to be able to accept inputs from 3 different water meters. Two of the inputs are 4-20mA signals, the third input being a pulse signal. At the top I have ...
2 votes
0 answers
56 views

Can the output of an L298N be smoothed using a capacitor to reduce buzzing?

I'm running some model trains with a Raspberry Pi using L298N modules to control motor speed. Traditionally, this would be done using what is essentially a DC motor speed controller, but I need ...
1 vote
3 answers
275 views

Separate two batteries getting charged by one charger with diodes?

I've got a robot that I use two batteries on. One of the batteries power the servos and engines and the other is for the digital boards. The servos need 5 V. The control board and LCD run on 5&...
0 votes
1 answer
357 views

raspberry pi 3V LED. What resistor to use? [duplicate]

I will connect this button with a 3V LED to RP3. what resistor should I be using ? Do not know the amperage of the LED. https://www.amazon.co.uk/sourcing-map-Momentary-Button-Mounting/dp/B07FYSR7Y7/...
0 votes
4 answers
59 views

What gauge wire is acceptable from 15 amp power supply with low current demands? [duplicate]

I am looking to directly power a Raspberry Pi for my 3D printer from its existing power supply. The terminals on the power supply appear to be ~15 amps max output at 24V. I already have a buck ...
0 votes
2 answers
427 views

Issues using an Ultrasonic Sensor with Raspberry Pi

I am conducting a project which needs to use a precise ultrasonic sensor but I am having trouble working it with the raspberry pi. The sensor I’m using is the Senscomp 600 series; the manual isn’t ...
1 vote
1 answer
185 views

How can i externally power 5 micro servos and one mg996r?

I am building a robotic arm with 5 * SG90 9g micro servos to flex each finger and one MG996R servo as an elbow joint. The servos were working inconsistently, with not enough torque and jittering a lot....
1 vote
2 answers
221 views

Splitting power to two devices (Raspberry Pi & LED Matrix)

I am working on a small project involving a Raspberry Pi and an LED matrix. Both devices are rated for 5V but requiring different current (approximately 2A for the Pi and 4A for the LED matrix). ...
1 vote
3 answers
986 views

Raspberry Pi reset circuit

After extensive research and finding very helpful circuits for the rest of the system I still have not found what im looking for. I am building a PoE raspberry pi weather station that will be mounted ...
0 votes
1 answer
64 views

How does my fan have active tacho (RPM) output even though the blades aren't turning?

Whilst working on a project to control and monitor an EC fan from a Raspberry Pi, I have encountered an anomaly that has me completely confused; the fan is still outputting pulses on the tacho line ...
1 vote
0 answers
38 views

Raspberry Pi RS422-485 HAT

I am trying to design a RS422-RS485 HAT with the schematic design that I found here: http://electroshed.com/wordpress/isolated-rs422485-for-the-raspberry-pi/ However, I would prefer the data-rate (...
2 votes
3 answers
1k views

Fine-tuning/calibrating DS18b20 thermometer via 1-wire

I am trying to enable remote reading of the temperature gauges in my furnace room by adding DS18B20 thermometers. Since I had some Raspberry Pis and DS18B20s, and ...
0 votes
0 answers
18 views

HC05 Bluetooth Module with Pi Pico Not Discoverable

I have a HC05 Bluetooth module wired up to my Pi Pico with the following code. ...
1 vote
1 answer
163 views

SI5351 I2C clock generator breakout board not detected on raspberry pi 3

I've recently bought a SI5351A I2C breakout board on Aliexpress (This listing) for a project. I was trying to test the board using a simple breadboard, a couple of jumper wires and my raspberry pi 3 (...
0 votes
1 answer
55 views

How to prevent self-charging in parallel UPS?

I'm trying to design an UPS for Raspberry Pi that only connects to +5V and GND pin. PMIC1 is a battery charger connected to a 5V boost. source U1 is a voltage supervisor that serves as UVLO (PMIC1 ...
0 votes
0 answers
33 views

Multiple power banks to handle temporary increase in power demand

I have 1 PoE+ (Power over Ethernet) port from which I need to power 5 Raspberry Pi 4s. The recommended power supply for Raspberry Pi 4 is 5.1 V / 3 A which gives 15.3 so 5 Pis will require up to 76.5 ...
-2 votes
1 answer
57 views

Why should I use printf for function works fine

I am trying to use Raspberry Pi Pico with C. I am taking data from RFID and trying to get decimal value from byte. I can take decimal value but I have a problem. I need to read 14 character from RFID, ...
0 votes
0 answers
72 views

APA102 (HD107S) LED strip noise problem

I built POV display with HD107S LED strip (similar to APA102), It uses Raspberry Pi 3 and ESC module to drive the motor. At first on the breadboard the POV works well, at this time the strip LED ...
1 vote
2 answers
90 views

MAX3232: Switch between RS-232 and TTL levels

Sorry in advance, electronics noob here! I need to make a proof of concept to get some data out of third party system which handles both RS232 and TTL levels. The computer/raspberry/arduino shall - I ...
0 votes
2 answers
557 views

How to reduce voltage with no earth?

I'm currently working with Raspberry Pis that are going to be powered through an LED night light (it is for being able to observe people working on experiments and giving light to the camera.) The ...
1 vote
3 answers
408 views

24V DC to 5V for powering a Raspberry Pi 4 and a router for a vehicle - what should i use? DC/DC converter?

I am looking for a DC/DC converter from 24V to 5V for powering 2 devices So this is what I got: A vehicle power box that will give off 24V -- This is my power supply A Raspberry Pi 4 Model B (Max ...
1 vote
1 answer
325 views

Stand-alone flashing of STM32

I'm developing a fixture tool to test a custom PCB with ST Bluenrg1 (STM32 M0 core + bluetooth). This fixture tool has its own MCU working at 5V. I would like to flash automatically first previous to ...
13 votes
1 answer
24k views

How to properly use a relay module with JD-VCC from Arduino/Raspberry?

I got two 4-relay-modules and I am probably doing something wrong because none of them seems to work: My first try was using a breadboard 5v power supply, connecting VCC and In1 to 5V and GND to GND. ...
2 votes
1 answer
460 views

Connecting BMS to charge controller and load

Im trying to design a circuit that the load will get power from solar panel or a battery (in case the solar panel will not deliver enough current\voltage) Also wanted to mention that this is a hobby, ...
0 votes
0 answers
93 views

Adafruit LCD Going blank when using static gun

I'm having a problem with an Adafruit touch screen Module. When I use a spark gun (set to 20kV) on a grounded metal plate (placed a meter away from the DUT) after a few tries, the screen goes blank. ...
0 votes
2 answers
405 views

How to use an optocoupler with a transistor on both sides?

I am trying to switch a 17VDC 30mA load with a Raspberry Pi. To provide electrical isolation, I am using a two channel optocoupler, a TLP621-2 (datasheet). The second channel is currently unconnected. ...
0 votes
4 answers
103 views

How does this RS485 transceiver work?

I'm attempting to communicate with an RS485 network with a raspberry pi pico, and I found a "hat" which includes a couple SP3485 transceivers, along with the supporting TVS diodes, etc. The ...
0 votes
0 answers
56 views

Surface scanning

I’d like to build a bowling ball surface scanner as a home project. Similar to a CD player using a semiconductor diode laser and a small photoelectric cell to read the surface. I would like to read ...
0 votes
1 answer
426 views

Raspberry Pi UPS circuit review request + improvements

Based on this question I created the following circuit: Since I made some (component) changes, first I would like to have a validation of the circuit for long-term usage (and some improvements). Used ...
0 votes
2 answers
838 views

Is it possible to drive a 12V DC motor with XL6009?

I am a beginner in robotics. I am planning to drive a 12V DC motor from Raspberry Pi 2 B. I know Pi does not have that capacity to drive such a device, so I am using L293D motor driver to control the ...
2 votes
2 answers
478 views

CE and FCC for MCU boards/Raspberry Pi HATs/Arduino shields etc

There doesn't seem to be a great deal of information on the internet about this (and the information that there is is usually contradicted somewhere else), so I'm going to ask this here, in the hope ...
0 votes
1 answer
35 views

candump and cansniffer are working but cansend is not working on Raspberry Pi + RS485 CAN HAT (MCP2515)

I connect it at 500k bitrate. Both candump and cansniffer are working, receiving a lot of messages. I've pinned down the packet ...
1 vote
1 answer
758 views

How to switch ON a Raspberry Pi, Arduino, ESP32, etc from SQW pin of RTC DS3231

My issue is how to build the circuit and what is the most efficient one to trigger a MCU from the alarm of the RTC DS3231. For the momment I have built the one in the picture below (using a P-channel ...
1 vote
2 answers
180 views

How to troubleshoot a (possibly fried) ws2812b led strip

I have a 4.5m, 60led/m Ws2812b strip, hooked up on a raspberry pi running hyperbian. Raspberry works on its own psu, and I have a meanwell 5v 18a for the leds with common grounds. The setup was ...
1 vote
1 answer
3k views

LCD driver board M.NT68676.2 issue: Screen compressed, fills only part of display

I am trying to build a portable Raspberry Pi/Retropie system with an LCD screen I got from my old laptop (the idea is to have a portable gaming console to be used in a car). To drive the screen, I am ...
0 votes
0 answers
100 views

4-20 mA Sensor to Raspberry Pi: Inconsistent readings

I have a 4-20 mA sensor that I want to read it with a Raspberry Pi. I use a DFRobot Current to Voltage converter board connected to an ADC (ADS 1115) that is connected to a Pi. So that way I can read ...
0 votes
1 answer
181 views

Circuit for high voltage pulses using raspberry pi PWM to drive a piezoelectric actuator

I am trying to engineer a device to separate red blood cells from blood plasma in 100mmx1mm capillary tubes using the raspberry pi GPIO pin PWM feature and a piezoelectric actuator. The pulses ...
0 votes
1 answer
523 views

CAN Bus with RS485 CAN HAT for Raspberry PI

I have set up a CAN bus between 2 STM32 Nucleo's, where one is only sending messages and the other one is only reading them. This works, I have also validated this by connecting them to another CAN ...

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