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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Extra spacing between some traces and the ground plane

I have seen several designs where there is extra spacing between some traces and the ground plane. For example, see the traces between the points A and B or C and D in the following picture (this is a ...
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Simple circuit with transistor using Raspberry Pi

I'm trying to use a Raspberry Pi to control a set of 4 LEDs. I'd like to control the LEDs in software by using a ...
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2answers
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How do I get 5V for a Raspberry Pi from 4 D batteries?

I'm hoping to run a Raspberry Pi and a hobby servo off 4x1.5V D size Alkaline batteries. The batteries are brand new and at the moment I am measuring 6.5V from the 4 in series. I'm guessing each cell ...
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Controlling a 3 speed AC ceiling fan motor with a Raspberry Pi

I have been trying to reverse engineer a ceiling fan remote control receiver to work with a Raspberry Pi Zero W. The light portion of the fan was easy enough to control, but I can't figure out how to ...
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1answer
5k views

Interfacing Raspberry PI to HoneyWell alarm system (3V vs 12V)

simulate this circuit – Schematic created using CircuitLab I've been working on a similar project as this but with a HoneyWell alarm system. I've managed to lower the voltage from the 12V or ...
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Sensing weight with strain gauge, InAmp, ADC & Pi

I have an SEN-10245 sensor for weighing objects (essentially a strain gauge). The goal is to capture data with a Raspberry Pi, so the signal from the weight sensor needs to be amplified and then ran ...
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997 views

Connecting 5V device to 3.3V input through a single resistor

Hi I've got a Raspberry Pi, that's 3.3V device, and a Nextion display, which is a 5V device. They are talking over UART. Obviously RPi's UART RXD link can be damaged if connected directly to the ...
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99 views

Trying to design a switchable LED circuit with no experience or skill - please send help

I'm trying to design a circuit to connect with an Raspberry Pi and have no idea what I'm doing... apologies in advance for terrible descriptions of my problem. I have some 1 watt LEDs (max fowrad ...
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1answer
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AVR ISP-Programing LEDs SCK

I'm using a Attiny45 microcontroller and USBtinyISP as my programer, and this is the first time I need to hook stuff up (in this case just LEDs, but eventually I'll want to conect a raspberry pi) to ...
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253 views

Optocoupler Question

I'm currently trying to create a system to open my apartment's door (using the buzzer) using my raspberry pi, and thought that using an optocoupler would be the best solution - although I'm a complete ...
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582 views

Raspberry Pi controlled power on/off switching of an Ethernet connection

I want to power on/off an (Gigabit) Ethernet connection physically by using some circuit. The main idea was to use a transistor with the Raspberry Pi GPIO to switch an Ethernet cable. The schematics ...
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1answer
64 views

Circuit changes, what is the input high and low given when the circuit is lit and not!

One change in the circuit, the R1 is not 4300 ohms but instead 4700 ohms. The voltmeter is the input into the raspberry pi GPIO board. What would be the input (voltage) when light gets to the ...
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Splitting mains power into multiple relay-switched circuits

Summary Introduction My goal is to split a 1-gang mains power extension lead into three, have my Raspberry Pi plugged into one of the outputs, and have the Pi able to switch the other two outputs ...
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Breadboarding a Raspberry Pi

Ok, long time reader first time asker on this parcticulair stack-exchange. I am rather new to electronics, I've done some simple projects like Blinking Lights, alarms that go on when its dark and a ...
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Using a digital potentiometer in a voltage divider

I'm using an MCP3008 ADC and an MCP4131-103 (10k) digital potentiometer to try and create a sort of "adjustable voltage divider." For the project, the resistance I'm measuring will vary, and I hoped ...
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663 views

Use ATX power source to power Raspberry Pi

I'm setting up several Raspberry Pi's and Arduinos connected together, and I'm looking for a way to power them. Would it be possible to adapt an ATX stock power source with female USB plugs using the ...
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1answer
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Choosing transistor for a raspberry pi switch

I'm trying to design a circuit that will control the power to a raspberry pi with a button. The basic usage is: first button press-> rasp powers up. second button press-> rasp continues with ...
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Is this a serial LCD?

I had a broken remote for a small RC helicopter that I took the LCD off. I dont know the size, but I could try to describe the pins and maybe someone could pinpoint what this is. It has 7 pins, and ...
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1answer
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How to switch a MOSFET to drive a 5v relay from Raspberry pi?

I've been trying to power my 5v relay through a MOSFET but I can't seem to get it to work. I'm using a IRLI540N with the gate to GPIO 24 that goes high when I click the pushbutton (that much does work,...
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3answers
589 views

ULN2803 not working like I expect, or at all

I am a total electronics noob trying to build a simple circuit for a jukebox that I'm making using a Raspberry Pi and an old jukebox wallbox. I'm a computer systems engineer by trade. And it's my ...
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1answer
2k views

Power consumption and frequency

I am making a small, mobile device with the Raspberry Pi that depends on batteries, so power consumption is an issue. I have scaled the "arm_freq_min" (unsure if clock or instruction cycle frequency) ...
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2answers
592 views

Raspberry PI audio over Cat5e wired ancient hotel intercom

My question is can I (and how might I with minimal insanity) connect the audio output of a Raspberry PI (and/or other USB audio outputs) via say some 10-30m of Cat5 cable to some 10 or so pretty ...
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1answer
2k views

Managing I2C address conflicts with multiple MCP23017 on the same bus

I'm using a Raspberry Pi with the I2C master and I successfully wired 8 different MCP23017 chips, each with their respective addresses by setting the last 3 bits of their 7 bit addresses. They are all ...
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213 views

Different ways to detect seals? [closed]

I would like to build an underwater mammal detector to take videos of seals when they get in and out of their cave (the entrance of their cave is underwater). It will be a waterproof sealed box with ...
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3answers
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Ground loop when measuring in process pH

I have been experiencing a very difficult to solve ground loop problem with my pH measuring system. My basic setup is a standard pH electrode running through an op-amp to an ADC which communicates ...
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1answer
894 views

How to start implementing your own computer? [closed]

The question As a first step I need to select a circuit board, CPU & RAM/ROM chips and I/O connectors. How do I select a board that can interconnect all these components? Perhaps you could give ...
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2answers
189 views

Doorbell Press for MCU

Situation I'm looking to add Raspberry Pi 3 near my door and detect when the doorbell is pressed. But I don't want it to change the operation of the chime (if Pi is off/unplugged, the chime should ...
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84 views

Is there a way to output high quality pictures to a monitor with VGA using an Arduino?

So, I had a spare monitor lying around and I wanted to find a way to make it like a picture slideshow. I also have an Arduino Uno. I was wondering whether there is a way to take some pictures from an ...
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2answers
173 views

How do I build a system for localizing sound source? [closed]

In my apartement I have the problem that when I am in my bedroom I can hear the neighbours in their bedroom exactly above me talking. Luckily I can not hear what they are saying but still pretty ...
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1answer
800 views

How to control PcDuino pins from Java?

When I had Raspberry Pi I used to control the GPIO (pins) from a Java application using the Pi4J library. Is there any library to control the GPIO (pins) on the PcDuino using the Java language?
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482 views

What should I use from given options to power a raspberry pi?

I have a system which consists of 2 12V DC motors(0.65 A on max load) and 1 RPi 2 model B. I want this system to be plug free. I have Li-Ion batteries to power up motors. I use a L298N module to drive ...
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External power for Raspberry Pi USB device

The Raspberry Pi's USB ports can only supply about 100ma of 5V current; this comes directly off the 5V input power to the board. The usual solution is to use a powered hub to support devices that ...
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3answers
4k views

NPN BJT Relay Circuit will not turn off

I'm applying a 3.3V signal with my Raspberry Pi to the base of an NPN transistor to activate a SPDT 6V relay (relay data sheet, model G2R-1-S-DC6(S)). The relay pickup/dropoff voltage is 4.4/0.9V. ...
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3answers
311 views

How can I seamlessly switch power supplies?

Quick question, I am not very good with my electrical circuit terminology so I'm not sure what to call what I'm trying to do. When I try to Google "How to switch power supplies" I got inundated with ...
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1answer
382 views

Logic Level Converter (3.3v <-> 5.0v) returning HIGH for Low Volt. & High Volt. sides when nothing is plugged in. [Raspberry Pi]

The Goal I have a Raspberry Pi that I'd like to control my treadmill with. The Pi's GPIO ports output 3.3v and the treadmill's motor control board only takes 5v signals. Because of that, I bought a ...
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1answer
392 views

Add 3.5mm Jack to Raspberry Pi for TTL Signal with 5V

I am a 100% software guy, so i wanted to confirm that my little project is gonna work before i fry everything. I am trying to create a controller for my (quiet old) Onkyo reciever. I am trying to do ...
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1answer
3k views

Coordinator + Repeater Xbee + End device configuration

I am trying to work on a Xbee based solution for transferring data from with in a specified area.I am using Xbee865LP for the same project. Now what i want to implement is Make one device act as ...
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1answer
2k views

How to restrain this soft latching power switch from eating too much current?

I am designing a two buttons soft latching power switch for a project involving a raspberry pi, li-ion cells I salvaged from the battery of a broken laptop, and a power booster from adafruit. I ...
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2answers
677 views

I fried my Raspberry Pi while using L298N but I don't understand why

Everything seems to indicate that I fried my raspberry pi: the green light wouldn't turn on, I changed the SD card for a new one but it still didn't work. That is a shame because I was having a lot ...
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0answers
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First PCB (raspberry pi hat)… can't find short circuit

INTRO: Hi there, everyone. I'm working on a RaspberryPi hat PCB that drives 10 solenoids and takes in 5 inputs. I designed the PCB on EasyEDA and had the boards printed at JLCPCB and used their SMT ...
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4answers
166 views

Stepping up three 3V3 outputs to 5V

I want to use the third solution from this answer to step up three of my GPIO pins from my Raspberry Pi. Would I need to make one of these circuits for each of the pins or could I, for example, ...
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1answer
58 views

control 3 status LEDs with 2 PCs

I'd like to control 3 status LEDs with two different PCs: an OrangePI-PC, using the GPIO pins as power source (same pinout of a RPi2); regular desktop PC, using the parallel port as power source. ...
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3answers
1k views

How can i drive this 5v Relay board with RPi?

Beginner here, so this problem came up: I got a 250vac 30A relay board which seems to require 5v to be driven. It has 4 input pins: GND, IN-, IN+, VCC What are the IN- and IN +? My rpi output ...
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2answers
535 views

Mechanical Switch in parallel to the Micro Controller working in Sync

Here is the image for my requirement,want to operate Load Lamp of 230V AC with Mechanical Switch in parallel to Controller where one can 'ON' the Load Lamp from the Mechanical Switch and 'OFF' from ...
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1answer
1k views

How to determine range of wifi module

I am starting to plan a project that involves either an Arduino or Raspberry Pi (haven't decided yet) connected to a number of sensors. The unit will be located outside, battery powered and will send ...
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3answers
334 views

Can I drive a BLDC driver with this diagram?

I'm a programmer and I've only started messing with hardware half a year ago, mainly with the Raspberry Pi. I now want to drive a brushless DC motor using my Raspberry pi. To do this, I've bought this ...
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2answers
1k views

Optocoupler w/ RasPi & Door Buzzer

I'm currently trying to make a system where sending a message to my Raspberry Pi from my phone will send a signal to my apartment's buzzer to open the front door, however I've been having problems ...
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1answer
139 views

Why is the MCP23S17 device getting too much hot suddenly and randomly Raspb 4A?

Circuit is a Raspberry Pi 4A SPI master node talking with one MCP23S17 device: datasheet. I'm testing the singlest circuit version in a protoboard. We are using A bank GPIOs for reading, and B bank ...
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1answer
470 views

Raspberry Pi- SPI with Hi-Res Bipolar ADC Chip (LTC1867). Wrong values being read

this is a follow up to my previous question "How to measure bipolar analog signal accurately (to 1mV) on raspberry pi" . I can't post more than 2 links yet but please have a look for some more ...
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1answer
387 views

TUSB2046B hub with raspberry pi zero

I'm using a TUSB2046B hub connected to a raspberry pi zero. The hub circuit looks like this: There appears to be a 12MHz sine wave coming from the crystal (as counted by my scope) and 3.3V on the ...