GPIO stands for General Purpose Input Output and can be used to receive and send digital signals to and from simple electronics from the Raspberry Pi.

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rPi model B + MCP23017 + relay board. GPA0 pin low output not close enough to 0v to trigger relay

I've setup a MCP23017 16-bit I/O expander with a rPi model B via i2c, and I am able to set its pins to outputs, and control components like LEDs on the channels using code like this; # set GPA pins ...
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3answers
32 views

GPIO pins: (3v3 and #pins) not providing power

The 3v3 gpio pins and all of the numbered pins are not providing any voltage. Or rather, very little voltage. I used a voltmeter to check the voltage difference between 3v3 and ground and the needle ...
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2answers
32 views

Count RPM/Frequency/Pulses on GPIO ports (Maximum?)

I'm planning to count the RPM of a RC Car which is controlled with a PI B+. But while planning the question occurs, how to count the RPM. My Idea is via a Sensor, which gives a Pulse every Round, and ...
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1answer
29 views

Building a two DC motor robot cart with rpi

I want to build a Robot which runs on Two DC motors have cart like structure , I want to control it using PWM. what is best way to do it directly from rpi without using Arduino or kits or modules but ...
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1answer
36 views

connecting LED to gpio pin without using jumper wire

Can I use Ordinary wire and wind it on a gpio pin instead of using a jumper wire to test aN LED? Will it damage my Pi?
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1answer
27 views

Power on 5V GPIO power pin at boot

I am new to the Raspberry Pi, so I wanted to describe my project along side my question. I have a functioning Raspberry Pi A+ and I am building a heads-up display using a MyVu Crystal. This link ...
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1answer
53 views

Is my Pi's GPIO damaged?

I am trying to test GPIO output on a Raspberry Pi, and I am wondering if it is broken. These setups work: 3v3 >> +LED terminal -LED terminal >> resistor >> GND (the LED is unusually dim here) 3v3 ...
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2answers
43 views

Is it possible to expand the PWM signal?

I'm looking at the WS2812B LEDs and I've noticed that it is possible to control the LEDs by an external library (https://learn.adafruit.com/neopixels-on-raspberry-pi/software). But, this only drives a ...
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2answers
30 views

RPi B v2.0 P5 header on RPi B+

I have the PiFi DAC v1.0 from VullersTech that requires the P5 header which only seems to be available on the RPi B v2.0 ("Made in the UK"). Are the P5 header pins somehow accessible on the RPi B+, so ...
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1answer
17 views

Controlling Brushed Motor ESC from the raspberry Pi

I've tried solutions from similar problems, but none of them gave me any usable results. I'm trying to control those http://www.ebay.com/itm/311177661450 ESCs with Raspberry Pi. I have tried ...
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1answer
44 views

Raspberry Pi GPIO input fluctuating

I'm trying to read the output of a photodiode sensor circuit by the Pi GPIO. The sensor circuit outputs roughly 3.3v, from an Op Amp when the sensor detects IR. Circuit Diagram: N.B Op amp is a ...
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2answers
60 views

Proper hardware debouncing my interrupt driven digital electrical meter input?

This is a child of my first problem, I am getting ghosting/bouncing on my digital input, but this question is more hardware related and specific to my problem. I have a RasPi model B. I have read ...
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1answer
123 views

Raspberry Hardware simulator to practice on

I don't own a raspberry (it's in the mail) and would like to practice coding and interacting with the IO ports to turn on LED lights. Is there an gui hardware simulator someone can point me too? ...
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1answer
52 views

Can Rasberry Pi drive a PCB speaker directly?

I have this PCB speaker I really would like to mount to my Rasberry Pi model B but I am not sure if I can connect it directly to the 3.3VDC and a GPIO? As far as I can tell it is from 0.1W to 0.2W as ...
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1answer
33 views

Gertboard to control 4 servos?

I have been given this arm: It consists of 4 servos, which need to be controlled individually. Can I control them using Gertboard? Gertboard has only one motor driver, but it also has several open ...
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1answer
20 views

Monitor/Debug SPI using another GPIO Pin?

ive trouble to get SPI working: loopback spi_test works MCP23S17 does nothing So i'm searching a wayto debug the SPI Bus. I thought i could monitor/log the MOSI bits using another GPIO Port using ...
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0answers
18 views

Serial line hangs after first call

I have written a short program to monitor a serial line using the uart on GPIO-Pin 8/10. It works fine the first time I start the program, but hangs without any output the 2nd time I call it. To be ...
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1answer
34 views

i want to set the alt function for the gpio in raspberry pi

I am working on the raspberry pi, doing changes in the machine driver. And there is a hack in the machine driver to change the alt function of one gpio. So i want to remove the hack and want to call ...
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1answer
28 views

Measuring frequency via GPIO

I'm trying to input the frequency of a 3.3V square wave on a GPIO pin as a program feedback parameter. The input frequency range would be 1000 to 100,000 Hz and data polling would happen at 30 Hz. ...
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1answer
44 views

Systel level differences in making a GPIO high in Raspberry PI vs Beaglebone

I understand the Raspberry PI uses the previous Kernel and the Beaglebone Black uses the one after and both do a great job for different applications. I would like to know what is the difference in ...
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1answer
20 views

Issues with multiple SDA sensors

I am facing some issues trying to connect two sensors which make use of the SDA GPIO. Ultra sound sensor HC-SR04 Gyroscope & Accelerometer MPU-6050 Separately, they work just fine, however ...
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56 views

Assembly - set gpio as input

I have 2 leds and one button. both green and yellow led off when booting from card. When the button is pressed, i want to turn green led off and yellow led on. However, I have to write assembly. I ...
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1answer
28 views

Enable GPCLK line for 1MHz (or greater) clock

I'm trying to drive a TLC5940 with a brand new RPi Model A+ (V1). I plan to use the Pi's SPI bus to pipe data to the chip, which I've done successfully before using an AVR. The part I'm stuck with is ...
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32 views

Java ME embedded has no effect on the raspberry pi's gpio

I recently tried following the instructions listed here: http://www.oracle.com/webfolder/technetwork/tutorials/obe/java/RaspberryPi_GPIO/RaspberryPi_GPIO.html#section1 I was able to do the extremely ...
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1answer
42 views

Pins I2C cannot be used as input

When using pin 3 and 5 as inputs, I get only 3.3v and I'm not able to use them as inputs. I use the same code and circuit on all the GPIO pins the circuit worked on every single pin except on this 2 ...
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14 views

How to do a repeated start with the Raspberry Pi to get the MMA8452Q accelerometer working?

I am trying to use an MMA8452Q accelerometer with the Raspberry pi B+. I have it hooked up to 5 GPIO pins on the Pi, J8 pins 1/3/5/7/9. After installing some i2c libraries, the Pi recognizes the ...
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35 views

How to get an IR sensor and motors to work together?

I've managed to connect a IR sensor to GPIO pin 23 and get LIRC to work with one of my remote controls. I've also set irexec up to launch a bash-script that drives motors (connected via open ...
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2answers
85 views

may connect 26 pin touchscreen display to a 40 pin raspberry pi A+?

Recently, i've got as a present a raspberry pi a+ (40 GPIO pins) and touchscreen display for older version (26 GPIO pins) I tried to google, but wherever i search it gives me description of the new A+ ...
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31 views

PySerial not responding after 10 seconds of inactivity

I've got the JY-MCU Bluetooth module connected to the hardware serial port on my Raspberry Pi. It seems to be working except for one thing: when there is no communication for about 10 seconds or more, ...
2
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1answer
116 views

How to connect a 12V fan sensor wire to the Pi

I have a 3-wire 12v DC fan (Sanyo Denki 9S1212M4011). It's actually getting 15V because my "12V" wall wart isn't accurate. When the fan is not running my multimeter tells me there is 14V on the ...
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105 views

TFT RPI LCD Screen doesn't work properly

I purchased a TFT Screen from dx to be a small monitor for my Raspberry, this is the screen: ...
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1answer
61 views

GPIO problems, when run infinitely goes to the right

I'm trying to get a controller to move right, preferably one space, using GPIO. I'm not quite sure what I'm doing wrong but whenever I run the script it moves to the right but it never stops. I don't ...
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49 views

Daisy Chaining MCP23017 & Addressing

I'm looking to daisy chain multiple MCP23017 chips (upward of 10) to essentially give me more IO to play with from my Pi. I've started to work on the circuit diagram, but I'm really lost with all ...
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1answer
59 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 ...
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1answer
48 views

Can GPIO measure 3-10ms input spike?

I want to measure speed with one infra gate. The width of the bypassing object is known therefore I could calculate the speed. However the infrared gate would be interrupted only for 3-10ms. I ...
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21 views

PIGPIO: Can child process use the parent initilized pigpio library?

I have a parent process (which is a basic tcp server). This process calls gpioInitialise() before forking a child process which polls gpio pins for input. After forking the child, the parent process ...
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2answers
155 views

5.3v power source into the GPIO

I bought a UBEC (Universal Battery Elimination Circuit), which, for those not familiar with it, is a "5 volt" dc-dc power conversion circuit (you can get them as high as 5A). It gets it's name from ...
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37 views

Receiving a nack (clockstretching) while measuring distance [closed]

So I have written a small piece of software in C to measure distance with an ultrasonic distance sensor and then print it to the screen: uint8_t TxData1[2] = {00,0x51}; uint8_t TxData2[1] = {0x03}; ...
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1answer
52 views

How can I detect if specific USB port is being used, and then command an action?

I'm very new to Raspberry Pi/Linux/Python world and I'm trying to identify one of the ports on my RPi, so if someone for example, connects a USB Flash drive (or anything) to that specific port an ...
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0answers
28 views

Switching a RS-360SH motor on/off

I'd like to know what electronic components I need in order to switch on/off a RS-360SH motor via a GPIO pin. I know the circuit needs to look something like this with a diode across the motor to ...
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1answer
32 views

'var gpio' INVALID SYNTAX in IDLE3, Raspberry Pi

I'm new to Python and Raspberry Pi. I'm trying to drive a stepper motor with the Rpi from this website: http://www.sundh.com/blog/2014/02/control-stepper-motors-with-raspberry-pi-and-node-js/ I find ...
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95 views

How do I run Piscope

I installed pigpio and ran with sudo pigpiod -p 8877 I have exported PIGPIO_PORT=8877 Following the discussion on How to install stripped version of GTK (without *dbg files)? I downloaded and ...
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1answer
83 views

Why is GPIO 16 on at boot?

I have a RasPi B+ running Raspbian and have connected an LED to GPIO 16 (pin 36) and another LED to GPIO 12 (pin 32). It is my understanding that the GPIO ports are all off (low) by default and ...
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1answer
45 views

GPIO interference

I want to use the rPi as a thermostat so I wrote this code. What it basically does it reads the temp and sends it back to the client, some client will then issue a command ON or OFF and based on this ...
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4answers
153 views

GPIO Pin 17 does not trigger RPi.GPIO callback

I'm trying to read from all my Raspberry Pi B+ GPIOs. Using the Python3 RPi.GPIO library, it is quite easy to do, but I've come across a problem that I can't seem to resolve : GPIO 17 does not ...
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2answers
190 views

What is a failproof method for testing a GPIO pin?

So, basically, I've been trying to get my raspberry pi to get the room temperature from a DS18B20 1 wire temperature sensor. I've read only GPIO 4 is capable of this, and I think for some reason GPIO ...
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1answer
37 views

UPS with battery reading

I need a UPS (Uinterrupted power supply) which I can connect via gpio to read if it is charging, the battery level, etc. Anyone know how I can make one or where to buy one from? Thanks
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1answer
66 views

Connect screen to rasp

I have disassembled a virgin router that I had left over at home, and managed to get this screen out. I am wondering if it would be possible to connect it to the raspberry to show time or ...
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1answer
93 views

How to get RPi to generate a triangle wave, then outputting a PWM signal

I want my Raspberry Pi B+ Model to generate a triangle wave and output a PWM signal from one of the GPIO pins, but I'm not sure how to go about doing this. All I want it to do is add some small length ...
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23 views

I2C Gertduino + Raspberry

I am struggling to install the I2C properly. When I connect the rpi with the gertduino and set the jumpers for the atmega48p I only have two entries in the matrix from i2cdetect -y 1: 10b: UU 30b: ...