FNR – Robot Mesh Network: Intro & Node 1

Posted by Erin, the RobotGrrl on Sunday, September 19th, 2010

I’m trying to create a network for my robots to communicate through and interact with the outside world to have some new behaviours emerge. Each robot will be able to read and transmit messages. The robots will be given basic instructions for things to listen to and eventually some behavioural AI to link previous commands together. The idea is to have robots talking to each other, informing one another of different sensor readings, thereby creating a shared knowledge of the environment that the robots are in.

In a military robots example, a UAV could be observing the environment below and an autonomous rover analyzing some LIDAR sensor data of its ahead of it. With some mapping algorithms applied and communication between the two robots, a rescue mission could be planned and executed very quickly. It’s all about networking the robots and making them talk together in “words” they understand.

Last Friday I worked on getting Twitter integrated with Processing. This weekend I added on to that existing work by trimming down the tweet string, and having it transmitted to an Arduino which broadcasted the message through the XBee to the other devices.

There are currently three devices on the network right now:
Node 0: Transmitter from the computer
Node 1: RoboGlyphs
and a Watchdog, which doesn’t transfer data, only reads what is being sent out.

Here is a video of a broad and basic explanation of everything so far:

The transmitter node serves as the main point of communication of the internet to the devices, and vice versa. It’s using an Arduino with an XBee attached to it. Right now its main purpose is to send out the tweet that it receives from the Processing sketch.

The transmitter node looks like this:

Which is attached to the computer running a Processing sketch:

The Processing sketch is connected to Twitter, and searches for tweets that are to @RobotGrrlsBots. The connection is through OAuth, since IP rate limiting for feeds resets less often, as far as I have observed. It sends the most recent tweet to the transmitter node.

The RoboGlyph node receives the tweet, and does what the command says. The command has to be formatted in the way of this:

If it is received OK, which is usually is, then it will display it! The process that the RoboGlyphs follow is that it fades in the colours, then it waits for a command. Once it receives a command, the colours will fade out.

This is what the RoboGlyphs node looks like:

And this is it working!

Pretty cool. The RoboGlyphs could use a tune up though by using one of the TLC594 16 bit PWM out chips. Right now the green LEDs don’t use PWM, so it makes the animation look choppy.

The Watchdog watches all of the data that is being transmitted and shows it on the screen. This is what it looks like:

It’s useful to try to debug some things. While making everything I was having trouble with the New Soft Serial library and Arduino 0019.

Next time I will be working on getting data transported back from the RoboGlyphs and sending a tweet. From there, it will be about adapting that code to all of the other robots too. This is just the start!

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Posted in: Programming, Projects, Robot.