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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0
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0answers
24 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
29 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 ...
1
vote
1answer
289 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
176 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
76 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 ...
0
votes
1answer
633 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
113 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
108 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
266 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
84 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 ...
3
votes
3answers
1k 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. ...
4
votes
4answers
1k 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
104 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
270 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
335 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
97 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
1k 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
376 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
46 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
3k 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
511 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
603 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
479 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
2answers
677 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
963 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
2answers
563 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
191 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 ...
15
votes
1answer
5k 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
145 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
177 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
309 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
76 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
2k 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 ...
3
votes
3answers
880 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 ...
19
votes
3answers
8k 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 ...
7
votes
4answers
690 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?