Raspberry Pi Stack Exchange
Raspberry Pi Stack Exchange

Questions tagged [electronics]

Use this tag for questions related to how to use control electronics from the Raspberry Pi, and how to control the Raspberry Pi from electronics.

273 questions
36
votes
4 answers

Using Raspberry Pi without a Linux OS?

I'm interested in using the Raspberry Pi as a pure embedded CPU unit, for the development of embedded applications. Since the Raspberry Pi has a powerful CPU with quite a bit of memory, it makes an excellent embedded board. Is it possible to use the…
FarhadA
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29
votes
5 answers

Circuit to safely power-down Pi

I want to use my Pi as an XBMC server in the car. The XBMC docs say that you should always use the shutdown command before disconnecting the power. I've been thinking that it should be possible to create a simple circuit with a capacitor and…
Nicholas Albion
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15
votes
6 answers

GPIO: Why wire button to ground rather than +3.3v?

In most examples I've seen of wiring buttons to GPIO inputs, the button is wired so that when closed, a circuit is completed between the pin and ground, producing a low input on the pin. A pull-up resistor is used to default the input value to high.…
howard10
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14
votes
4 answers

Is it possible to use the GPIO to program a PIC?

I'm referring to the PIC microcontrollers, specifically the 16f and 18f series - could the GPIO be used in this way? If so, how?
berry120
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11
votes
5 answers

What is an easy way to electromagnetically shield a Pi?

My friend and I are working on a Civil War telegraph project, and we incorporated a Pi into the project, for reading and displaying the received code from the key. My friend created a period correct sounder, which relies on an electromagnet. …
fr00ty_l00ps
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10
votes
7 answers

How can I turn an GPIO to its alternate function?

I want to use the altenate function of GPIO 4 namely the GPCLK0 function. How can one set a GPIO to its alternate function? Many alternate functions are summarized here: elinux-wiki The best would be if it is possible with the wiringPi Library. But…
user61664
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8
votes
3 answers

Calculating resistor value for transistor

I'm creating a circuit with an infrared led and a transistor connected to a gpio pin. I'm currently using 5v with a 40 ohm resistor (four 10 ohm resistors chained) but I'm not sure what resistor to put on the transistor. The only transistor I have…
user61421
8
votes
5 answers

Is there a component out there that can push a button i.e. will extend a rod about 1 inch and then retract it?

I'm basically trying to find something that can push a button for me. I want to be able to control it through code, just like you can with motors, LEDs etc.. via the GPIO on a Pi. I want it to extend and retract fairly quickly (1 second or less) and…
Force Hero
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8
votes
3 answers

Powering a 3-12V water pump on raspberry pi

I've got a 3-12V water pump, a raspberry pi, a relay (5V 10A/120VAC, and a breadboard power supply supply 3V-5V. The questions are : Is it possible, to rspi to breadboard power supply usb, and a pump to it's 5V output? I don't want to burn rspi 5V,…
Jan Hoffmann
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7
votes
2 answers

Are resistors required for builtin PWM fans?

There are many guides on how to set up a 5V fan for a Raspberry Pi and control its speed with PWM. Usually, this includes using a a transistor a resistor between the PWM pin and the transistor gate a resistor between the PWM pin and the ground…
Uko
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7
votes
3 answers

How fast is GPIO+DMA? Multi I2S input

I want to connect multiple I2S ADCs to RaspberryPi and record multi-channel audio. I calculated that it requires copying GPIO input port to RAM at 3072kHz (or every 0.33µs). I want to do it using DMA. I know that PiBlaster (PWM) and PiFM (radio…
adiblol
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6
votes
2 answers

Electrical characteristics of GPIO

Is there a spec sheet anywhere which lists the electrical specifications for the varios GPIO pins on the RPi revision B? For example, if they are open collector etc, output voltage, max input voltage, max sink/source current, and so on? I assume…
Jayy
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6
votes
1 answer

How to add isolation between raspberry pi and relay board?

I want to use my Raspberry Pi to control mains(fans,lamp on 240v). Its very difficult to procure a good and reliable relay board for me in India. After bit of searching, I have decided to go with Seeed Studio's Groove Relay. Here are details:…
avi
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5
votes
2 answers

Powering 2 servos with 5v output of L298N dual motor driver

I am using L298n Dual Motor Controller to control two dc motors for my robot. But I want it to power the servos too. I have created this circuit design. can I power the SG90 Servo with L298n? Is there any fault in the circuit? Any Other suggestion…
Anshul Bansal
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5
votes
1 answer

Correctly grounding a circuit

I have a very simple circuit using the Adafruit breakout Pi cobbler kit with a HC-SR04 ultrasound module. The circuit works fine (I can trigger and read the echo back) but it doesn't seem to be correctly grounded. It only works when I put my hand…
Ross
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