How much can I strip out of a Roomba?

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How much can I strip out of a Roomba?

Postby ps0001 » January 5th, 2019, 1:29 am

Paging Vic...

I have a project for an outdoor robot in mind that could benefit from a Roomba's navigation algorithm for total coverage of an enclosed space. Before I get started, I was wondering if anyone knew how few sensors a pre-Wifi 400-600 series Roomba needs to function.

My idea is to take the motherboard, bump sensors, and maybe RCON from a Roomba and adapt its signals to drive two motors. I'll feed it tach signals from motor encoders. I think I can get away with leaving the IR wall sensors, cliff sensors, dirt detect sensor, brush deck, bin, and maybe the stasis sensor disconnected. What do you think?

If not, I can simulate the signals from most all of those things.

Also, I'm concerned that IR signals will get washed out outdoors, but it'd be nice to have the robot dock automatically...
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Re: How much can I strip out of a Roomba?

Postby vic7767 » January 5th, 2019, 7:18 pm

First question is, how large of an outside area do you want this modified bot to run in? There is an issue with Roomba navigation whenever nothing is encountered to interrupt forward movement after traveling 12 meters. Either an IR signal or obstacle event must be detected.
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Re: How much can I strip out of a Roomba?

Postby ps0001 » January 5th, 2019, 9:45 pm

See, I didn't know that! The area is about 39' x 50', about 12m x 15m. I'm not sure if the processor compares its motor PWM to the tachometer signals, but if not, I can just run the tach signals through a frequency divider.
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Re: How much can I strip out of a Roomba?

Postby Brett » January 7th, 2019, 8:49 pm

AFAIK (and I'm no expert) you can ignore the halo and front caster movement (stasis?). The cliffs and wheel-drop switches must report a 'healthy' signal to allow it to start. Bumper switches must be present to allow it to start, and (as Vic mentioned) needs an occasional signal to prevent a logic stop.

That's all I can think of.

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Re: How much can I strip out of a Roomba?

Postby ps0001 » January 7th, 2019, 9:06 pm

Brett wrote:AFAIK (and I'm no expert) you can ignore the halo and front caster movement (stasis?). The cliffs and wheel-drop switches must report a 'healthy' signal to allow it to start. Bumper switches must be present to allow it to start, and (as Vic mentioned) needs an occasional signal to prevent a logic stop.

That's all I can think of.

(-8

Thanks! I was thinking of keeping the RCON (halo?) sensor so the thing might be able to dock automatically, but that's good to know about the front caster/stasis sensor. I bypassed the cliff sensors on my 530 because of the black rug problem, so I'm sure I can do the same here. I'm thinking the wheel-drop switches must be just as easy to circumvent.
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