Additional bumping sensors

[passie]

Hi there,

I'm quite new to the Roomba robot's so i you feel this is already been asked please point me to the right direction.

I would like to add 2 additional bumping sensors on top of the Irobot (581)
So my question would be A) is this possible , B) is there already some sort of manual flying around on the internet on how to-do this ?

With regards,
Passie

[mfortuna]

I assume you mean soft-touch IR LED based sensors? You could just relocate two of the existing ones. I am not sure how they are wired but if they are in parallel so any one IR sensor can detect an approaching wall then you should be able to add two more. One thing to keep in mind is you need to provide power to the IR LEDs. I believe they are modulated so you would need to tap into the existing LED string without affecting power to it.

[passie]

Thank you for your reply.
Indeed I mean the soft-touch IR LED's. I would like to add 2 additional led's on-top of the Irobot.
This way it can detect closest which are a bit higher then normal.

Could you tell me which one I should buy and is there a schema somewhere ?

[Gordon]

...Indeed I mean the soft-touch IR LED's. I would like to add 2 additional led's on-top of the Irobot. ...
Could you tell me which one I should buy and is there a schema somewhere ?

I believe the greatest amount of information (outside of iRobot's Engrg Dept.) about Roomba-R3's Soft-Touch system will be found in this thread: viewtopic.php?f=1&t=15647

Read those pages to learn what has been discovered. I think you will eventually learn / decide that your project is doomed for the reason that Roomba's micro controller and its firmware must participate in your project by processing additional data collected from the extra pair of sensors (2 IREDs + 2 PTs) you would add. There is no information on this board regarding customization of Roomba's firmware to suit special projects.

[passie]

Thank you, I'll go trough the pages.

[mfortuna]

Now that Gordon has reminded me of the SCI manual I would say you still have some hope. If a bumper sensor pulls the processor pin low when it detects an object you could wire photo-transistors (PTs) in parallel with two of the existing PTs. You have to pick which PTs you want. If either the upper or lower PT detects light then the MCU would see it as coming from one PT.

Then you have to figure out how to power the IR LEDs with the modulated signal. You would have to figure out how the LEDS are presently driven and then somehow add them to the circuit. I think you are going to need an o-scope to proceed with this project.