I’ve tried advice which uses apt-get to purge “python{,3}-rpi.gpio” and then to install it again, but to no avail. Can anyone advise if the script works on a Pi2 and if not how might I use the pan and tilt module on my Pi2

(base install is 2015-05-05-raspbian-wheezy)

Thanks
Roddy

Thanks for the reply.

I understand a little better the relationship between angles and pulse.

Regards.

Sorry for the delayed reply. The exact relationship between angle and pulse width will vary a bit depending upon which brand of servo you’re using. In general the correspondence will usually be 1000us = 0 degrees, 1500us = 90 degrees, and 2000us = 180 degrees, although you’ll need to experiment to find the exact relationship for your servos, and also you may find that some servos don’t go all the way left or right. This article on the Society of Robots website gives a good explanation of servos and PWM signals. Although they quote times in millisections (ms) where 1 ms = 1000us.

Hope that helps.

Regards

Alan

I found your exemple very helpful but i have a problem. I don’t understand how to get angle and pulse width.

Regards

I think I’ll have to wait until the ADC is available since I’d like to avoid using an Arduino on top. I’m planning on deploying the system where there is no mains power and so it would need to run on a (big) battery. The smaller the power consumption will be the better.

Chris

Yes, this sounds like it would be a very cool addition to the project.

You’re right that you’d need an ADC, which the Raspberry Pi currently lacks. We are hoping to stock an ADC for the Pi soon, but in the meantime a good alternative might be an Arduino compatible such as the Mini Driver board we sell. I think that adding an Arduino to a Raspberry Pi project can be a really good option as it can be much easier to hook up sensors (analog and 5V) to an Arduino, and you have a little bit of onboard processing power that can be used to monitor sensors and control motors in realtime whilst the Pi gets on with more computationally intensive tasks.

Regards

Alan

I really like the setup for the pan/tilt camera here. Would it be possible to extend this setup to use a 2-axis joystick for input (controlling the camera, eg http://www.adafruit.com/products/512) with the necessary parts and code?

I’m guessing a ADC would need to be used to convert the analog signal to digital.

The end result would be that the user did not have to type any commands but could use the joystick to control the servos.

Thanks,

Chris

Sorry for the delayed reply.

The Mini Driver is Arduino compatible, so can be used with the Arduino IDE, which should be installed by default on your Pi, or can be downloaded for Windows etc. We have a blog post for getting started programming the Mini Driver here. Also, the Arduino IDE comes with lots of demo programs, including a Servo example which can be found by selecting File > Examples > Servo > Sweep.

So to answer your question, you’d need to write a sketch for the Mini Driver to control the servos, and then if needed, use serial communication to send commands from the Pi.

Hope that helps.

Regards

Alan