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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2
votes
2answers
58 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 ...
3
votes
4answers
178 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 ...
0
votes
1answer
43 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 ...
0
votes
0answers
28 views

Difference pifacedigitalio and wiringpi2 piface ouput pins

I would like to use a stepper motor connected to the piface with the wiringpi2 python module. I found some code online for testing stepper motors. import pifacedigitalio as pfio pfio.init() def ...
0
votes
0answers
34 views

GPIO pin PULL_DOWN would

I have set up a Arduino to send a 3.3V signal to my RPi if an object is detected in front of the UltraSonic sensor. I have measured the signal at 3.26V. But it does not work. Since the signal from ...
0
votes
1answer
49 views

Connecting RPi GPIO into a relay that draw high ampere

So straight to the problem I need to connect My RPi's GPIO to a (or some) relay(s) that consume around 30 - 60 Amps to fire up and RPi GPIO only give around 16 mA/Pin(Accroding to this). My question ...
1
vote
2answers
70 views

My 3V relay doesn't work on GPIO but works on 5V pin with resistor

Ok, I have this awkward situation. I have a 3V relay that I need to implement in my project. When I connect it to a 5V pin on RPi, everything's working fine, I can hear the coil opening and current ...
3
votes
3answers
334 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 ...
1
vote
3answers
123 views

Plant watering installation

I'm building a device, which can water my plant after certain input. The whole problem I've got is connecting a water pump to RSPI - I more or less understand that I need a relay, but is it possible ...
0
votes
0answers
114 views

Powering 3.5 inch LCD screen and RPi with 7.4V Lithium Polymer Battery

I am attempting to create a portable Raspberry Pi. I am wondering how I would go about running the RPi and the LCD screen from the same battery. The screen draws about 6.5V. I have a 5V voltage ...
0
votes
1answer
1k 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 ...
3
votes
1answer
662 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 ...
2
votes
1answer
86 views

How to start making and designing a raspberry pi “shield” [closed]

I would like to design a "shield" (arduino terminology) that will sit on top of the pi connected to the GPIO pins, although I have no idea how I should go about starting the design et.c Does anyone ...
2
votes
1answer
54 views

Is it okay to operate relay boards with less than voltage specified?

I was watching this video where the user explains that he is using Raspberry Pi to trigger the relay board, which requires 5v. But he says it's okay do it with the 3.2V that's from GPIO. Does doing ...
-1
votes
1answer
71 views

Voltage controlled current amplifier [closed]

How to amplify current 1A, 5V from the 5mA, 5V??. More Particularly, In input side, i have 10mA and 5V and output side required 1A, 5V. Thanks.
0
votes
1answer
74 views

Multiple sensors on one GPIO

I would like to know is it possible to connect for example: thermometer and pressure sensor to one GPIO? Thanks.
3
votes
2answers
362 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 ...
0
votes
0answers
57 views

Can the GPCLKn be used to provide an accurate clock signal for external microcontrollers and logic?

I have a hardware project based on an AVR microcontroller which must be clocked at 13.875 Mhz. The crystal for this is relatively expensive and quite difficult to obtain compared to the other ...
0
votes
0answers
123 views

Controlling a standard Bulb & Fan with Pi

I have been playing around with Pi for sometime now, and I am now able to do basic wiring to control LED using the command line of Raspbian in my Pi. However, now I want built something real. I want ...
2
votes
1answer
1k views

Raspberry PI as intercom?

I am currently looking for a way to connect an intercom to the raspberry pi, at the moment, the intercom wires are connected to a regular telefphone ( only two wires needed ), when someone dials the ...
2
votes
3answers
620 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 ...
0
votes
1answer
185 views

Replace USB port with USB cable RPi Model A

Is it possible to remove the USB port on a model a and solder on a 4 wire USB cable? I know that theoretically it is possible but does anyone have any experience actually doing this? If anyone has ...
1
vote
1answer
1k views

Is an external pull-up/down circuit mandatory for GPIO pins?

3 days ago I bought my first Raspberry Pi and it's a rev.B. I read that it provides through GPIO pins either 3,3V or 5V and the GPIO pins can handle between 2mA and 16mA each one. Moreover, to avoid ...
3
votes
2answers
145 views

5.8V Electrical Short = half baked 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 ...
1
vote
1answer
119 views

Is it harmful to write to a GPIO pin when there is nothing hooked up?

Is it possible to harm the Raspberry Pi by writing to a GPIO pin through software when there is nothing hooked up? From what I understand, this should not do any damage, but I want to make sure.
6
votes
4answers
390 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 ...
1
vote
1answer
104 views

Environmental Tolerance

I am planning a use for the RPi where it will be permanently connected to a car via the CAN-BUS. While other questions have discussed the stability of power, I am more concerned about the ...
4
votes
2answers
2k 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
2k 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 ...
1
vote
2answers
120 views

Roadmap to leverage RPi to do signal processing from 4 inductive loops and data transmission in an outdoor environment [closed]

I'm currently weighing my options to build a semi-industrial outdoor device, which is aimed to do some signal processing from 4 inductive loops which have been laid in the ground to detect vehicle ...
0
votes
2answers
385 views

Best source for raspberry pi sensors and accesories [closed]

this is a bit of a vague question but I have been building my own pi robot and am just getting to the stage where I wish to start adding some sensing capability however I am not an experienced techie ...
2
votes
1answer
487 views

Run model train with RPi [closed]

I am trying to figure out how to run my model HO scale train using my Raspberry Pi. While I have found videos on YouTube of people operating their model via RPi, I can't find any way to do it myself. ...
0
votes
1answer
109 views

what limits the number of LEDs I can connect to the GPIO

if I just want to simply connect LEDs to the +3.3v pin and ground pin, what limits the number that I can connect? for example using green LEDs with a voltage drop of 2.2v, I can only connect one with ...
1
vote
1answer
2k views

Cheap USB powered hub to work with the pi without backfeeding

I am trying to build a 3D printer farm with the pi, and I need a large USB hub. I found this hub. But don't know how to evaluate if its any good. Has anyone tried something like this? Do you have a ...
0
votes
2answers
492 views

Does anyone know of any Accelerometers that are easy to use in Python

I'm fairly new to GPIO programming and robotics with the Raspberry Pi, and was wondering what I should look out for to avoid pitfalls later when buying an accelerometer. I've heard that the GPIO pins ...
2
votes
2answers
60 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 ...
1
vote
2answers
4k views

How to get an SPI Analog-to-Digital (MCP3204) working with the GPIO?

I have an MCP3204 12-bit Analog-to-Digital Converter (ADC), and a Raspberrypi. Does anyone know what I need to plug where to get them to communicate? Is there an SPI python library I can use? O am ...
2
votes
4answers
613 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
3answers
869 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 ...
2
votes
3answers
532 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 ...
2
votes
3answers
978 views

Capacitor C6 dislodged

I managed to break the C6 capacitor on Raspberry Pi Model B. Its the 220uF 16V EE6 capacitor. Nobody seems to have such low capacitance, low voltage capacitor (the least I can find is 220uF and 60V). ...
2
votes
2answers
1k 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 ...
4
votes
2answers
834 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, ...
5
votes
1answer
237 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 ...
16
votes
1answer
7k 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 ...
3
votes
3answers
150 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 ...
1
vote
2answers
186 views

Need help with (ambitious?) project

I gave up on using my Pi as a VPN'd NAS, since the CPU is too slow to handle OpenVPN (see here Low bandwidth internet over VPN). So I want to set it up to do (all of) the following: Control a light ...
3
votes
2answers
365 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 ...
0
votes
2answers
89 views

eda tool to validate basic circuits [closed]

I am new to electronics but am a hobbyist. I plan to use the GPIO headers on RPi to drive simple circuits. I would prefer to design simple circuits on some eda tool but also validate them. That will ...
6
votes
3answers
3k 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 ...