What hardware should I start with..??

Hi hersey..., i am making a project in which i have to interface accelerometer

sensor, GPS modem and GPRS modem with Raspberry pi. can i write the

above devices interface coading in C language. is it ok, with the

hardware.

hrpreet,

As a rule of thumb, yes raspberry can control through the C language, sensors such as an accelerometer, a GPS, and a GPRS modem - and pretty much everything as the whole kernel is written in C.

But you need to tell us what interfaces are using the devices you want to connect.

If the GPS and the GPRS are connected through USB - the easiest way - you can easily control them through a USB-to-serial port, just opening the port as a file and reading the NMEA data - GPS - or using AT commands - GPRS.

The accelerometer, can be an UART, I2C, SPI ... and yes you should be able to control any of those through the GPIO pins, but to be able to do them without a level switcher depends greatly in the voltage levels supported by your sensor - the Raspberry GPIO are 3.3 volts.

So there is pretty much no information in your post to let people help you, as you are not even pointing to what kind of sensors you are talking about.

hrpreet,

As a rule of thumb, yes raspberry can control through the C language, sensors such as an accelerometer, a GPS, and a GPRS modem - and pretty much everything as the whole kernel is written in C.

But you need to tell us what interfaces are using the devices you want to connect.

If the GPS and the GPRS are connected through USB - the easiest way - you can easily control them through a USB-to-serial port, just opening the port as a file and reading the NMEA data - GPS - or using AT commands - GPRS.

The accelerometer, can be an UART, I2C, SPI ... and yes you should be able to control any of those through the GPIO pins, but to be able to do them without a level switcher depends greatly in the voltage levels supported by your sensor - the Raspberry GPIO are 3.3 volts.

So there is pretty much no information in your post to let people help you, as you are not even pointing to what kind of sensors you are talking about.

Hi,

     Im going to interface accelerometer, GPS, GSM module to Raspeberry Pi through USB only. Im getting trouble in the Coding... I need your help in the coding to interface all this device to Rpi.

     If the coding is in C or C++ that would be very help full for me.

You should at least post what devices you are using.

There is no way to help if we don't know what you are interfacing with.

Usually those USB devices open USB-to-serial port.

The GPRS modem is driven by AT commands, in the documentation of your device should come what AT commands it supports.

The GPS data use to be in NMEA format, this is a open C library to read NMEA streams http://nmea.sourceforge.net/

About the accelerometer I have no idea, I have only used I2C accelerometers.

You should check if your raspberry opens the devices com port and recognizes them. Just plug one and use the "dmesg" command to see the kernel output.

If it says something about /dev/ttyACM0 or /dev/ttyUSB0 - that's 0 or 1 or 2 ... - then your device is recognized and the USB to serial port created.

You can use the "cat" command as root and is some garbage or text is spilled to the console, there is output from the device.

To read from it usually just involves to open the port as a file.

FILE* fd;

int char;

fd = fopen("/dev/ttyACM0", "rw");

if( !fd ){

     return 0; // error cant read com port

}

while( (char = fgetc(fd)) != EOF ){

     // you have output in "char"

    // do whatever you need with it

}

If your raspberry don't opens the port you should check first if the physical connection is working with the "lsusb" command. This should output the device name if the kernel can detect it on the usb hub:

Example output is:

$ lsusb

[iago@ironforge ~]$ lsusb

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

Bus 002 Device 036: ID 0424:2504 Standard Microsystems Corp. USB 2.0 Hub

Bus 003 Device 002: ID 046d:c016 Logitech, Inc. Optical Wheel Mouse

Bus 007 Device 002: ID 413c:2005 Dell Computer Corp. RT7D50 Keyboard

If it's recognized but not mounted as a usb to serial port first and foremost check the documentation of your device. If it is not a serial device and you have the protocol data you can use libusb to interface with it.

If it's a serial device you may have to do an udev rule to have the dev entry made for you, from the idVendor, idProduct and serial number of your device from the kernel output.

Anyway, it would be much much better to start a new thread so people who knows about those issues can help you, than to keep writing on this one where people just see it's about something completely unrelated. If the title matches the content of the thread is much easier to get people involved in it.