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by xian
Mon Jun 17, 2013 10:10 pm
Forum: Linux Kernel
Topic: Writing a driver for my hardware project (I2C based)
Replies: 2
Views: 1411

Re: Writing a driver for my hardware project (I2C based)

My driver will expose an interface to control the hardware in it's logical form so that userland sees motors, outputs and IR messages, and not the I2C chips that control them. I expect it will use the existing I2C bus drivers but add something to sysfs. Maybe add a dir for each motor containing a fi...
by xian
Mon Jun 17, 2013 8:41 pm
Forum: Linux Kernel
Topic: Writing a driver for my hardware project (I2C based)
Replies: 2
Views: 1411

Writing a driver for my hardware project (I2C based)

So I've made a hardware project that uses some I2C chips (including a micro controller I've written firmware for) and I would like to write a driver so that shell scripts (or anything else) on the Pi can control it. The overall concept of the hardware contains three sections: 1) A set of 8 motor dri...
by xian
Mon Jun 17, 2013 7:53 pm
Forum: General discussion
Topic: Home Geysers
Replies: 2
Views: 663

Re: Home Geysers

yarx wrote:i want to make a home geyser system
Could you please explain what one of these is, and how you currently go about switching it on and off.
by xian
Mon Jun 17, 2013 7:49 pm
Forum: General discussion
Topic: Connect to cell phone
Replies: 4
Views: 1136

Re: Connect to cell phone

I use my phone to access my Pi but probably not quite how you are intending: I have enabled the SSH server on the Pi and use a combination of Connect Bot and Hacker's Keyboard on my android phone so that I can use command line on the Pi over my WiFi. It won't display the Pi's screen, but it would be...
by xian
Sun Jun 16, 2013 9:41 am
Forum: Automation, sensing and robotics
Topic: Problem using Tx Rx pins after auto start
Replies: 4
Views: 957

Re: Problem using Tx Rx pins after auto start

Also be aware that by default Raspian runs a terminal on the Tx/Rx pins. You will probably need to disable that if you haven't done so already.
by xian
Sun Jun 16, 2013 9:35 am
Forum: Automation, sensing and robotics
Topic: Lego motor controller and IR reciever
Replies: 11
Views: 5062

Re: Lego motor controller and IR reciever

@Gbaman The BrickPi does look good. I backed it a little while ago and when mine arrives I will get a few NXT parts to use it with. I am actually shifting my approach. I'd rather see the Raspberry Pi to communicate to Lego motors by sending IR commands. That is an option I considered, though placing...
by xian
Mon Jun 10, 2013 12:12 pm
Forum: Automation, sensing and robotics
Topic: Lego motor controller and IR reciever
Replies: 11
Views: 5062

Re: Lego motor controller and IR reciever

I want to put a Pi between the IR receiver and the motors, so that I can add more stuff, for instance, a sonar to stop the car when it's about to hit a wall, or a webcam. It is aligned with what you want to do, right? That's exactly what I'm doing. I have a lego model that I built that pick up an e...
by xian
Thu May 02, 2013 10:09 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Unexpected I2C Bus speed
Replies: 4
Views: 6188

Re: Unexpected I2C Bus speed

I would suspect that the bus pirate isn't exactly up to scratch in measuring high frequencies - it also probably doesn't take into account the fact that I2C will have long periods of idling between bytes, for example because the hardware is waiting for more data to transmit. Ok so on your suspicion...
by xian
Wed May 01, 2013 10:08 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Unexpected I2C Bus speed
Replies: 4
Views: 6188

Unexpected I2C Bus speed

I have been communicating with an AVR chip using I2C which seems to work fine up to around 250kHz. The problem is that the default speed the RPi uses seems to be around 500kHz (and when loading kernel module i2c_bcm2708 with baudrate=100000). Is this behavior to be expected? I've been measuring the ...
by xian
Fri Apr 12, 2013 6:37 pm
Forum: General discussion
Topic: Programming ON the RPi
Replies: 1
Views: 522

Re: Programming ON the RPi

I have compiled java code on a PC and executed the class files on the RPi. Just make sure you compile for the version of java you are running on the RPi and you should be fine. The RPi will run the compiler too if the jdk is installed.
by xian
Sat Apr 06, 2013 8:46 am
Forum: General discussion
Topic: cross compile problem
Replies: 5
Views: 1642

Re: cross compile problem

I seem to remember having a similar problem. IIRC it was because the execute bit was not set on something. Might be the symlinks.
HTH
by xian
Thu Apr 04, 2013 7:55 am
Forum: Automation, sensing and robotics
Topic: Raspberry Pi temperature sensor
Replies: 6
Views: 3427

Re: Raspberry Pi temperature sensor

First see if you already have the driver, please post the output from

Code: Select all

 zcat /proc/config.gz | grep ^CONFIG_SENSORS_TMP102
It may produce no output.
by xian
Wed Apr 03, 2013 6:03 pm
Forum: General discussion
Topic: Sending data to web host/server
Replies: 12
Views: 20003

Re: Sending data to web host/server

FTP opens two (minimum) connections: one for control and one for each file uploaded. Personally I would look into using something like a RESTful API and dump into it a compressed archive if you need to upload more than one file at a time. That would be my guess at the easiest way to upload stuff wit...
by xian
Wed Apr 03, 2013 5:16 pm
Forum: General discussion
Topic: Sending data to web host/server
Replies: 12
Views: 20003

Re: Sending data to web host/server

The RPi is able to use web services and FTP. Either should be fairly easy and too taxing for the RPi. There are many ways of doing both.
by xian
Wed Apr 03, 2013 5:08 pm
Forum: Automation, sensing and robotics
Topic: Raspberry Pi temperature sensor
Replies: 6
Views: 3427

Re: Raspberry Pi temperature sensor

I am using the TMP102 . It is easy to use and has an output that goes high when a programmed temperature is reached, that could in your case be used to operate a fan. Although this feature could also be implemented using a GPIO from the RPi using another temperature sensor such as the DS18B20. There...
by xian
Wed Apr 03, 2013 4:41 pm
Forum: General discussion
Topic: Sending data to web host/server
Replies: 12
Views: 20003

Re: Sending data to web host/server

Using python/curl to do a HTTP POST or PUT will work for images as well as the GPS data if you don't want or can't have an FTP server. I also highly reccomend learning some PHP, what you can code will probably dictate how you transfer your data.
by xian
Wed Mar 27, 2013 3:50 pm
Forum: Automation, sensing and robotics
Topic: DC Motor Speed Control
Replies: 3
Views: 4975

DC Motor Speed Control

I have noticed that DC motors that are required to drive forwards and backwards with variable speed are usually driven using an H bridge (e.g. L298) and PWM. Direction can be set on inputs a & b, and the enable line switches between driving the motor and allowing it to coast. Now I am putting togeth...
by xian
Wed Mar 27, 2013 1:49 am
Forum: General discussion
Topic: How to brake motor with wiringpi?
Replies: 29
Views: 4079

Re: How to brake motor with wiringpi?

I'm really not sure that this idea of fudging a 1 on all L298 inputs will stop the motor, all that achieves is to connect both wires from the motor to +Ve via 2 power transistors. One would need to conduct in reverse to work.... As you say a 1 on all the inputs allows a (conventional) current to fl...
by xian
Tue Mar 26, 2013 8:01 pm
Forum: General discussion
Topic: How to brake motor with wiringpi?
Replies: 29
Views: 4079

Re: How to brake motor with wiringpi?

It depends on what circuitry you are using to drive the motor. Please give details and we may be able to help you.
by xian
Sat Mar 23, 2013 10:57 pm
Forum: General discussion
Topic: Running WinSCP as sudo
Replies: 5
Views: 7287

Re: Running WinSCP as sudo

If you will be the sole user to write to /var/www you could chown it to yourself, or there are other ways of using the permissions. Using root privileges seems a bit overkill to me.
by xian
Sat Mar 23, 2013 10:52 pm
Forum: General discussion
Topic: GPIO from kernel space
Replies: 3
Views: 1273

Re: GPIO from kernel space

Thanks. Ok, so this just go a whole lot more involved than I was expecting. Currently I'm just using the gpio_request_*() and the like found in linux/gpio.h . I guess there is no similar kernel functions to perform this. So the procedure is (correct me if I'm wrong): - acquire the GPIO lines with gp...
by xian
Sat Mar 23, 2013 9:33 pm
Forum: General discussion
Topic: GPIO from kernel space
Replies: 3
Views: 1273

GPIO from kernel space

I am beginning my venture into kernel programming by writing a simple driver to read and toggle some GPIO lines. All is going well expect I cannot find any documentation on how to enable the pull up resistors from kernel code. Can anyone point me in the right direction please?
by xian
Thu Mar 21, 2013 11:02 am
Forum: General discussion
Topic: files and directorios permissions
Replies: 10
Views: 51416

Re: files and directorios permissions

What are you using to share the directories? Relevent sections from /etc/exports or /etc/samba/smb.conf would be good to see.
by xian
Tue Feb 19, 2013 12:25 pm
Forum: General discussion
Topic: help neederd
Replies: 4
Views: 578

Re: help neederd

If you could you could be more specific as to what you want help on, it will be easier to help you.
by xian
Sat Feb 16, 2013 10:38 pm
Forum: C/C++
Topic: Serial communication with 328 on Gertboard
Replies: 4
Views: 1940

Re: Serial communication with 328 on Gertboard

Personally, I would have only one process (or section of code) open it once, and then have that part manage interaction with the 328 between any other process that wants to access it. I don't understand your setup well enough to be able to recommend anything more specific. Edit - Gordon and I just p...

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