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.

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32
votes
4answers
17k views

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 ...
29
votes
5answers
28k views

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 ...
11
votes
6answers
14k views

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 ...
10
votes
5answers
5k views

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 ...
10
votes
4answers
2k views

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?
8
votes
3answers
8k views

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 ...
8
votes
5answers
11k views

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 ...
6
votes
3answers
10k views

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. ...
5
votes
5answers
6k views

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 ...
5
votes
3answers
4k views

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 ...
5
votes
2answers
2k views

Easy way to switch on and off of 12V DC current

I recently bought a compressor and now I want to be able to turn it on and off programmatically using my Raspberry Pi Model B. Since I know nothing about electronics, it seems like the safe option ...
5
votes
1answer
4k views

Do I need a current limiting resistor in series with a magnetic door sensor?

I'm building an alarm system and I'm using a magnetic door sensor, conected to ground and a pin of the gpio set up with an internal pull-up resistor. As far as I know, this means that the pin will be ...
5
votes
1answer
12k views

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 ...
5
votes
4answers
3k views

How can I combine many inputs on one pin?

Forgive my naivety but I seem to lack a vocabulary for the whole electronics domain... I'm interested in building something to measure wind direction. Inspired by this design I would like to build a ...
5
votes
1answer
1k views

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 ...
5
votes
2answers
3k views

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, ...
4
votes
5answers
3k views

How to read values from an clamp-on ammeter with an raspberry pi?

I want to use a clamp-on ammeter (like this one) to detect whether a table saw (230V) is switched on or not. The clamp-on ammeter is meant to be used with a volt meter and has an 1 mVAC / A output ...
4
votes
3answers
4k views

I am getting ghosting/bouncing on my digital input

I am meassuring data pulses from my electrical meter, giving me one pulse per Watt used. I have 4 electrical meters connected to my Raspberry Pi model B. I have connected them directly like this (no ...
4
votes
4answers
712 views

Did I destroy my GPIO board?

I bought a 30mm DC fan to cool off my Pi. It worked just fine if I plugged it into the 5V and GND pins. However, I wanted it to be programmatically controlled, so I plugged it into pin #18 and GND. ...
4
votes
2answers
1k views

Use 3.3V regulator on 5V rail with GPIO

I would like to run a the LD1117H linear 3.3V regulator on my Pi's 5V rail in order to provide more current than the 50mA that the onboard 3.3V rail provides. My concern is that this is not entirely ...
4
votes
2answers
14k views

Can I control this ESC/Brushless Motor with a Raspberry Pi and/or Arduino

My friend and I have been reading up on articles talking about controlling ESC/Brushless Motors from a Arduino or Raspberry Pi. Articles i've read give caution on the idea that controlling such ...
4
votes
2answers
2k views

Using RasPi to send signal, for locking / unlocking alarm clock?

I'm totally new to electronic/hardware/interfaces/GPIO sort of thing, but I have a project in mind. My house has an alarm system, which can be unlocked by key, with buttons. The alarm system gives a '...
4
votes
3answers
1k views

Controlling a relay with GPIO

Is it possible, using the GPIO Port to power a relay. I have read things about the GPIO port saying it is very easy to mess up, and seeing that activating a relay (basically a short circuit through a ...
4
votes
2answers
117 views

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 ...
4
votes
1answer
6k views

Connecting a standard telephone through GPIO

I am wondering if you can interface a standard, RJ11 telephone through GPIO, and input an output through the phone, even using asterisk to connect to voip. The phone I have is a GE model number ...
4
votes
4answers
4k views

Logic converter for relay module or extra resistors and transistors?

I would like to use a 8 channel relay of SainSmart for house automation: http://www.sainsmart.com/8-channel-dc-5v-relay-module-for-arduino-pic-arm-dsp-avr-msp430-ttl-logic.html This Relay module ...
4
votes
2answers
2k views

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 ...
4
votes
2answers
1k views

Cannot open 12V Solenoid Valve

I am a beginner in DIY electronics, and I am attempting to control a 12V Solenoid valve from a Pi B2 connected to a 12V Battery and WiringPi Pin 1. I am using a 1kOhm Resistor between the gpio pin ...
4
votes
0answers
90 views

Raspberry Pi wild boar reppelent [closed]

In my father's farm, he may face a problem with wild boars. There are currently too many of them around. They already came to my father's farm but they did not destroy anything (there's not much to ...
4
votes
5answers
1k views

GPIO to hifi amplifier's trigger input (remote power on). Protection? Circuit?

I use my raspberry 1 B+ with a DAC board (like hifiberry) and volumio/moode audio distribution. The board is working as a pre-amp and it's connected to my hifi amplifier RCAs input, sending analog ...
3
votes
2answers
2k views

Power USB hub and Raspberry Pi with the same PSU

I am still searching for a solution to conveniently power some external hard drivers. I would like to use only one AC plug as I think it is not very efficient to use two different PSUs. My idea is ...
3
votes
1answer
3k views

Common ground with 9V?

I'm new to pi's extending. I've a MB102 breadboard, coupled with a powersupply. I plugged a 9V power supply, and it's working (powersupply => resistor => led on). I'd like to interface some ...
3
votes
2answers
659 views

Using an L293D chip (to control a motor) with a separate power supply

I've got an L293D Motor Driver chip powered by 4.5v via some batteries and am trying to send high signals via the GPIO library in Python to control a motor, however this does not seem to work. My code ...
3
votes
2answers
101 views

Is it normal to read a connection between pins 2 and 4 of a GPIO breakout board?

So, I recently bought this cobbler kit from adafruit, and finished up the soldering as they instructed. However, after doing so, I hooked the cobbler up to my breadboard to test the connections. I ...
3
votes
3answers
2k views

How to turn on a high current electrical device? (water heater)

I am looking into a project to measure the temperature inside a water heater and turning it on based on: time, temp, etc. I am only on the theoretical phase since I am not sure it is possible. I ...
3
votes
1answer
843 views

Using WiringPi with Jasper (voice recognition)

I am using Jasper. The voice control part works, however the function I call when a certain word is said, does not. I'm trying to control a robot, sending high signals to certain pins on an L293D ...
3
votes
1answer
2k views

Not getting 3.3v from GPIO Pin

I hope this is the right place to ask this kind of question. I'm quite new to this, so I expect there is a simple explanation. Basically, I have a small electro magnet (the type from an old doorbell)...
3
votes
3answers
2k views

Has anyone manage to drive a HD44780 LCD using a 74HC595 shift register?

Using Python, I am trying to interface with a HD44780 16x2 LCD display and would like to save a few pins from my Pi's GPIO banks by using a 74HC595 shift register. So far, I have managed to run the ...
3
votes
1answer
235 views

5.8V Electrical Short = half baked Pi (or, questions about damaged but still working Pi)

I just shorted 5.8V+ (4 half-done AA batteries) through my Pi... at most for 3 seconds... it went through somewhere near the ethernet port... whilst connected to the ground of the circuit, also ...
3
votes
3answers
853 views

Which platform is best for project? Raspberry vs Arduino?

[CAVEAT: Very basic question from someone who not yet even at the "newbie" stage. Please forgive is the question is too basic and/or poorly formed. --thank you!] I work for a small start-up firm ...
3
votes
2answers
189 views

Electronics manual for noobs

In my faculty course I didn't have any introduction to electronics... just programming. So I want to start small thinks with the GPIO of the raspberry pi but I even to plug a simple led is not ...
2
votes
3answers
2k views

reverse engineering: Transcend digital photo frame display to Raspberry Pi

I have a Transcend [TS-PF705B] digital photo frame lying around with me for a while. And since the day i got this unit, i always gave a thought to do some thing with, like hooking it up with my ...
2
votes
1answer
757 views

Reversed LED in GPIO Output

I want to make a circuit where I can control 2 LED's with one GPIO pin. But my question is if this would be possible and/or harm the Raspberry Pi because of the negative flow? Is there another way or ...
2
votes
4answers
2k views

Raspberry pi and shift register

I have a project using a Raspberry pi and an 8 bit shift register to pull one of the 8 pins to ground if an event occurs, but leave it at 5 v 99% of the time. Ideally this will be done with Python, ...
2
votes
4answers
356 views

Rasberry Pi for a tractor

I am just starting Raspberry Pi and I am far from being a guru in electronics. I want to know: Is Raspberry Pi shock proof? Can it handle vibrations and bumps? I have seen some dust proof containers ...
2
votes
2answers
151 views

Is it safe to drive a current between a GPIO output at 0V (LOW) and the 3.3V supply?

Normally I would drive a current between a GPIO output at 3.3V (HIGH) and GND, for example to light a LED (with a resistor included of course). I am now wondering if it is safe to drive the current in ...
2
votes
2answers
5k views

How to control 12V DC motor with a NPN transistor, a GPIO pin and a 12 V DC power supply

I wish to control a 12V dc motor through the GPIO pins of a Raspberry Pi. I am currently referring to this tutorial. I have a 2N222 NPN-transistor which will used as a Switch, a 12V-2A power supply, ...
2
votes
2answers
2k views

Simple DC Solenoid Valve Circuit, How to size components?

I'm trying to build a circuit controlled by a 3.3V GPIO pin on a raspberry pi to open / close a 12VDC Solenoid Valve. Part of me feels I'm in over my head and I should back away slowly, but hopefully ...
2
votes
2answers
109 views

Is there a display that can be turned on/off via a Pi?

I have seen many small displays that work with the Pi, however I am wondering if any of them can be turned completely on/off via the Pi. If so, what should I look for? many are GPIO based (especially ...
2
votes
2answers
7k views

How to measure DC current RPi?

I have recently bought a Raspberry Pi, and I would like to be able to measure the current flowing through the circuit in our Greenpower electric racing car. It would also be useful to record this for ...