Category: BeagleBone

Sonar sensor on the BeagleBone part 1, direct approach

When building a robot one needs to use sensors. I used sonar sensors before for this post:

https://fleshandmachines.wordpress.com/2011/09/16/arduino-double-sonar-with-ros/

The main idea is to get rid of the Arduino on our rover “Scarabeus” and use the sonar sensor directly on the BeagleBone. The problem is that this sensor needs a 5V pulse to trigger ultrasonic output and it also answers with a pulse according to the received incoming signal but all the GPIOs on the BeagleBone operate at 3.3V. There are several possible ways to solve this and I’m presenting two of them here.

  1. Do some electronic hack and apply the sensor directly onto the BeagleBone.
  2. Use a dedicated 5V chip to handle the sensor and communicate via serial port (uart) to the BeagleBone.

This article will describe the first one, the direct approach. (more…)

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BeagleBone pin layout cheat sheet

I’m not good with memorizing things.

After two weeks of working with it I got bored of reading the BeagleBone manual over and over every single time I had to use a pin so I created this “pin layout cheat sheet” that can be printed and hung on the wall.

Enjoy!

Image

Born of the Firebug rover or an old friend is back

Yesterday we went to our evil genius friend  to ask him to make a new rover for us. Instead of making a new one we ended up reviving an old rover.

This rover was our robot in the competition of Magyarok a Marson 2011 (Hungarian on Mars). The competition was similar to a capture the flag game, with four rovers on the field at the same time.
We weren’t that experienced that time (and our budge was low) so the project failed. We were good in the first round but unfortunately at the second round some smoke has been made and the motorcontroller went to the robo-heaven. Also we smoked an 25A car fuse, yeah something was very bad in our design. We didn’t have the automatic control in time so we used the manual version. In this case we had to use 15 sec delay between two command to follow the rules. We started the blog roughly after two months to the competition. Here is a picture of the rover at that time.
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mjpeg-streamer on BeagleBone

Now that we are done with the platform we have to attach some sensors.
I had some experience with webcams and mjpeg-streamer so I thougth it’s is time to create the BeagleBone version.
I used the latest demo image with 3.18 kernel.
I have an Canyon Wc 23 type webcam(CN-WCAM23). When I plugged it in, the kernel modules and drivers loaded automatically without the need to install anything. You can still make sure that everything went well by typing:

lsusb

(more…)

Web interface for a BeagleBone controlled robot

Given a situation where one needs to implement a simple RC interface for a robot. What’s more straightforward? We could create a thick client and implement a server application for the robot but that’s too complicated. In order to have something light-weight and portable I was thinking of implementing the RC interface using some HTML and possibly some cgi.

The outcome of this tutorial will be a webpage that looks like this:


(more…)