I²C stands for Inter-Integrated circuit, and is a data transferation system that allows connections between computers and low-level peripherals.

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I2C stops working if a DiBcom DVB USB adapter is plugged

I can't help to get my I2C device (an Adafruit Pi Plate I just bought and built) to work in my Raspbian machine. Although the command sudo modprobe i2c-bcm2708 showed no errors, something strange ...
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is there a library for raspberry pi to use with MMA8452 I2C Three Axis Accelerometer Module?

I bought this accelerometer : http://www.fasttech.com/products/0/10000007/1012002-mma8452-i2c-three-axis-accelerometer-module I would like to use it with raspberry pi, I know that it is possible ...
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2answers
52 views

I2C with zener protection isn't working

I wanted to put some protection on my PI's pins and chose the zener voltage protection one, as described here. I used TZX3V3A zener diodes and 330 ohms resistors. Like this : Then i tried to ...
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3answers
124 views

How to use 2 x MCP23017?

I need to control 32 L.E.D's individually, now looking through the forum, the common solution is to use MCP23017 chips, as they can control 16 l.e.d's. With that in mind, I would require two chips. ...
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75 views

How to connect more than 1 am2315 temp rh sensor to respberrypi

Hi I have to read temp and rh from 2 locations. so I bought 2 am2315 sensors which is i2c logiced temp rh sensor. I connected it as shown in the below diagram, and its working fine. I can read data ...
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89 views

Disable i2c in Raspberry Pi

I want to disable the i2c in raspberry pi, so that I can use it as GPIOs. I commented the lines in the /etc/modprobe.d/raspi-blacklist.conf, but not working.
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396 views

Controlling Multiple analog RGB 12V led strips

I need to control several (5 to 10) analog RGB strips which have a separate power supply at 12V or 24V. Just like this one for example. I need to control the intensity of each colour channel for each ...
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1answer
60 views

Connecting Raspberry Pis With I2C

I would like to connect 6 slave RPis to 1 master RPi via I2C. Has this been done before and is it even possible. I know the I2C interface on the RPi has 1.8K pullup resistors so having all of those ...
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3answers
5k views

Safest way to connect Raspberry Pi to Arduino Uno R3

I am working on a robot using an Arduino Uno R3 and I wanted to have the ability of controlling the Arduino wirelessly, like stopping the Arduino without having to pull the power-plug every time. I ...
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1answer
214 views

Control a SainSmart 20x4 LCD?

I've got some SainSmart 20x4 LCD left over from my Arduino projects and I wanted to check if and how it's possible to get them running with an Raspberry Pi. I've come across this question. ...
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640 views

I2C devices not detected

I'm running raspbian on my pi and followed this tutorial to get the i2c going. i2cdetect -y 1 used to detect my i2c devices but doesn't anymore. The sensor is connected like this: Could this be a ...
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i2c data understanding [closed]

let me first say that I'm somewhat of a noob when it comes to i2c and serial communication. I've been trying for 2 days now to grasp it, reading datasheets, youtube videos etc. And I'm having a hard ...
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3answers
1k views

How can I automatically update the hwclock with NTP when I have internet connection

I'm using an RPi with Raspbian which runs the NTP-daemon by default. I have connected an rtc-ds1307 external i2c hardware clock. I was following the instructions given here to set it up: ...
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3answers
1k views

Analog input to the PI

I have a bit of a specialized question for you. Recently I got my Pi up and running, and am amazed at what it can pull off. But I want more. I want to be able to record the output from an ...
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1answer
501 views

Raspberry Pi/“Arduino” communication

I'm looking to use a raspberry pi to speak to multiple "arduino" ATMEGA328p ICs (through a logic-level converter). I figure I can do this reasonably well over the GPIO RX/TX and use qualifiers to let ...
2
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1answer
474 views

How to install smbus to virtualenv?

How to setup python-smbus in the virtual env? Pip does not find any appropriate package. Is there a way to make main python installation's libraries visible to virtual env?
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3answers
844 views

Raspberry Pi and BMP085 (I²C)

I tried to get the temperature and pressure with the BMP085 sensor and my Raspberry Pi (256MB) via I2C. I used this Adafruit tutorial: Using the BMP085 with Raspberry Pi, but this isn't working for ...
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1answer
228 views

HD44780 Character LCD C++ Library

I'm looking for a way to connect my Raspberry Pi Model B to my HD44780 LCD, I've tried the Rpi-hw C++ Library but to no avail. You can find the issue about it here. I've been looking ever since for a ...
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1answer
662 views

Meaning of cmd param in write_i2c_block_data

I am testing i2c communication between Pi and Arduino. The doc says: write_i2c_block_data(addr,cmd,vals) Block Write transaction. int addr,char cmd,long[] None I have this test: On Pi: ...
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142 views

SPI , I2C interfaces of Pi

I was going through this article : http://www.airspayce.com/mikem/bcm2835/ Under the heading "Real Time performance constraints" it talks about the constraints and says that "This means that you ...
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353 views

I2C (via BCM2835 library) and a mysterious error

The main function I'm having a problem with is where I'm writing a value to external EEPROM. I clear the EEPROM, then write my value to it, waiting 100ms afterwards. #define BAUD_RATE (int)100e3 // ...
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2answers
489 views

Connecting to an LCD via I2C

I'm trying to use a SainSmart 20x4 LCD connected via I2C. I can manually drive pins 0 & 1 to high and low so I know they work. I've commented the blacklist I2C-bcm2708 and blacklist SPI-bcm2708 ...
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1answer
554 views

What does UU mean for RasClock

I acquired a RasClock made by After Thought Software (http://afterthoughtsoftware.com/products/rasclock) . This is a real time clock using i2c. I wanted to play with its other features via i2c but ...
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1answer
1k views

i2cdetect doesn't catch ANY address. How can I tell if I2C working correctly?

I'm having difficulties interfacing the Raspberry Pi to basically any I2C sensor. I've gone through a lot of tutorials on how to get the I2C driver to work and my connections are correct. Still, ...
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Controlling 400 LEDs from a raspberry pi

I have a client who has several large bronze signboards, each with 100-150 little light bulbs on it, totaling approximately 400 bulbs. The bulbs are turned on and off on a schedule, currently by hand ...
2
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1answer
3k views

I2C cable length and type

I have made some tests with a temperature sensor tmp102 connected with 1m long cables and it works great. Now I am wondering if I can use a 10m long cable and if yes, what type of cable shall I use? ...
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2k views

Using the wiringPi I2C Library

I am trying to figure out how this library works (https://projects.drogon.net/raspberry-pi/wiringpi/i2c-library/) . Firstly, what is int fd that all the functions require. It is never stated. I can't ...
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1k views

How to get pin addresses on a MCP23017

Recently I purchased a few MCP23017. I've been reading up on them and I've gotten a few lights to turn on and such. I am having a problem trying to understand how to figure out the register address ...
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1answer
2k views

MMA8452 I2C module

I am working on Raspberry Pi Model B. I am trying to interface this device over the I2C Bus on the Rpi. My hardware Connections are: RPi Accelerometer Vcc P1_1 ...
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1answer
204 views

Detect version 1 or version 2 Pi

I'm writing a small application that could run on version one Pi ( mine ) or a version two ( co-workers ) that uses the I2C bus. Since the I2C bus is different depending on the version, I was ...
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365 views

Converting two's complement hex values to binary using PHP

I'm reading x-axis accelerometer data from an IC via the I2C bus using I2C-Tools' ( specifically i2cget ) in Linux. Here is the code that is reading these values: $OUT_X_L_A = shell_exec( 'i2cget -y ...
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245 views

How can I read and write data to a Character Device File in Linux with PHP?

I'm trying to read and write to modules on the I2C bus on a Raspberry Pi using PHP. I'm using fopen() and fskeek(). Below is the code I've been trying to use to read data coming in from the physical ...
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2answers
1k views

I2C: Raspberri pi as a Slave

I am trying to make two raspberry pi communicate through I2C protocol. I got little information that how I can code as a master in C using i2c-dev.h. So my question is how to make one of my raspberry ...
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0answers
504 views

Raspberry Pi on AVC-LAN / IEBus

I'm planning on using my Raspberry Pi in my car as an XBMC server. I'll be able to select songs/videos using the Android remote control app, but it occurred to me that it would be really neat if I ...
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1answer
948 views

Connecting the HMC6352 compass module to a Raspi using I2C

I am trying to connect a HMC6352 compass module to my Raspberry Pi. According to the datasheet I need to send an "A" for a read command. However, I am somewhat new to I2C and do not know how to ...
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221 views

Variaty of sensors sitting on a single board for RPI

Is there a board that has a few different sensors sitting on top of it and able to talk to RPI via I2C/1-Wire?
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428 views

I²C frequency changeable?

Is the I²C frequency meanwhile changeable? I read a few articles a while ago, that the frequency is not changeable.
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323 views

Couldnt get any value from accelerometer

I am using accelerometer MMA766 to read values. Used the following commands root@raspberrypi:/home/pi# i2cdetect -y 1 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- ...
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1answer
703 views

Xenomai RTDM Skins for I2C, SPI

In another post I read that Xenomai could be used for real-time tasks like control loops. I'd need to implement a real-time task which also talks to I2C and SPI. In this mailing list message I read ...
3
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1answer
1k views

PREEMPT_RT and RPi Drivers

I'm planning to do some realtime control loop tasks with the RPi. In this post PREEMPT_RT and Xenomai were proposed. I'm thinking about trying PREEMPT_RT, as I'd like to keep it as simple as possible. ...
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2answers
995 views

i2c Group on Arch

I'm trying to get I2C to run on Arch Linux with Kernel 3.6.11+ #352 PREEMPT with Raspberry Firmware from Jan 9, 2013 updated via rpi-update. So far I have got good results by just loading the i2c-dev ...
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1answer
750 views

Configuring to read RTC at boot time

I have added an RTC to the I2C bus of the Raspberry Pi. If I follow the steps mentioned here (I am using the DS1307 RTC IC), I can run hwclock and read the time. root@raspberrypi:~# modprobe ...
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2answers
2k views

I2C library for Mono/C#

Is there a library to use I2C bus on RPi for Mono/.NET? I was trying to find anything, but there are only libraries to work with GPIO but not with I2C.
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1answer
632 views

What is the difference between i2c-dev and i2c-bcm2708

I have been trying to figure out how to use i2c on RaspberryPi, and the What is the difference between i2c-dev and i2c-bcm2708 mentioned here? I would assume the i2c-bcm2708 module is specific to the ...
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3answers
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Is there an i2c Library

Is there a simple library to talk to i2c for C++? I have found some stuff for python and Java, but I wanted C++. I was hoping someone has ported the Arduino Wire library so I could use code I have ...
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1answer
434 views

sample speed i2c

If running standard release of debian on my Rpi. How fast can I sample the sensor readings through i2c and save values? Why Im asking, I tried to read a DS18B20 and save it,s values (wrote the ...
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296 views

Current state of I2C in Kernel and Kernel version in general

I need to use kernel drivers for some I2C peripherals, so I need kernel I2C support. As already discussed in a previous question, the current 3.1.9 kernel doesn't provide support for the SoC's I2C ...
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2answers
13k views

How to use a DS18B20 temperature sensor in my Pi?

I have a few DS18B20 temperature sensors. These are normally used in Arduino but I don't see why not to use them in a Pi. There is a software called DigiTemp that seems to drive the device and I have ...
7
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2answers
5k views

How to make raspbian load the i2c-dev module on boot up

I have installed 2012-07-15-wheezy-raspbian, and the i2c-dev module and i2c_bcm2708 are there and work with i2c-tools. How do I get the i2c-dev module etc. to load at bootup?
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1answer
2k views

How do I bit bang I²C master?

I've installed RPi.GPIO. It doesn't support I²C yet, but can I use it to bit bang I²C? I would just need the Raspberry Pi to be the master.