Making a Roomba run Half Speed?

[jkunkel2]

Im working on a project that involves modifying an iRobot Roomba to do another task. In order for my project to work, i need the robot to drive half speed, all of the time. I have read that people have issues when the front sensor lense gets dirty, and it makes their robot runs at only half speed. I have been unable to re-create this situation reliably and consistantly. I have tried many ways of blocking these sensors, but no luck.

Does anybody have any ideas on accomplishing a half speed Roomba??

How hard is it to reprogram the speed?
What kind of algorythm controls the speed and these sensors?

Any and all feedback would be greatly appreciated.

thanks!

[vic7767]

The Light Touch sensors on the 500, 600, and 700 model Roombas are responsible for slowing the forward speed of the robot. There is an Open Interface document that is used to communicate with the Roomba using the Serial Command Interface port. That document contains the commands that you can use to control the direction and speed of the robot.

Depending on what model you are using there are two different Open Interface documents for communicating with the Roomba. One is for the 4XX and 4XXX models and the other for the 500, 600, and 700 Roombas. Both can be found in the hacker forum or on the iRobot website.

[jkunkel2]

Thank You for the Quick Reply!

im not sure if programming is going to be possible for me, since it is quite above my level of computer skills. Any other ideas, or further info would be greatly appreciated.

[jkunkel2]

Just out of curiosity....... Could anyone explain the process of reprogramming speed?? What software/hardware would i need? Im a programming dummy, but maybe with a little head start i could get this figured out.

[vic7767]

There is no programming that needs to be done. The commands that are sent to the Roomba are documented in the Open Interface document provided by iRobot.

You might try using a 3x5 white index card and attach it to the front bumper. It's possible that if positioned in a way to reflect the IR signal back to the receiver it may slow the robot.

[mfortuna]

One possible way to do this is to add a magnet to the encoder disk inside the wheel assembly. The robot wouls see twice as many tach puldes which could fool it into running at half speed.

If you use SCI you really need a wireless connection (or a mind control if that is still available and if it works with the 500 series). You can make the robot drive around and even respond to stimuli.

But you can't change the existing firmware to change the speed.

If the robot sees a constant IR bump due to the index card it may cause an error.