DIY Roomba Virtual Wall

Recently, my Roomba virtual wall broke. Not sure what happened. I did a battery change, and the darn thing will not power up after the new batteries were inserted.

Anyway, while looking online for a new virtual wall to buy, I came across info on people making their own virtual walls. Here is a links dump:

1. https://petezah.com/category/development/roomba/
2. https://www.thingiverse.com/thing:3104027
3. http://blog.batmule.dk/posts/2019/Roomba_Virtual_Wall_part1/
4. http://www.robotreviews.com/chat/viewtopic.php?p=65658&mobile=on
5. https://misc.ws/2014/02/27/diy-virtual-wall-for-roomba/
6. https://misc.ws/2014/08/09/diy-virtual-wall-for-roomba-part-two/
7. http://www.enide.net/webcms/index.php?page=virtual-wall-for-roomba
8. http://eka.tomeczko.pl/index.php/diy-roomba-virtual-wall
9. http://gregthielen.me/blogstuff/2017/06/27/roomba-virtual-wall/
10. https://github.com/MKme/Roomba
11. http://forkthings.com/2016/11/25/diy-an-irobot-roomba-virtual-wall/

Turns out it is extremely easy to produce the IR signal emitted by the virtual wall. It's basically 0.5ms mark, 7.5ms space, 3 times, followed by 132ms of rest (based on the info given here), over a 38KHz modulation frequency.

I decided to test the idea using a simple ATtiny85-based circuit on the breadboard:

 

The test program is as follows:

#include <Arduino.h>

#include <tiny_IRremote.h>

IRsend irsend;

void setup() {
  irsend.enableIROut(38);
}

void loop() {
  for (int i=0; i<3; i++) {
      irsend.mark(500);
      irsend.space(7500);
    }
    delay(132);
}

My initial attempt using the IRRemote library found in Arduino's Library Manager didn't work, though ATtiny85 is supposed to be supported.

Being the lazy bum that I am, instead of trying to debug the library, I simply googled around and found another IR remote library called tiny_IRremote. I downloaded the library and changed the include file, and to my amazement, the test circuit worked on first try!

The IR LED that I was using on the breadboard was the one salvaged from the broken virtual wall. I also tested another IR LED that I removed from an old TV remote, as well as a IR LED that I found in the original Arduino kit purchased many years back. They all worked without a problem (at least with the two 500-series Roomba in my possession).

Now that the proof-of-concept works, I am going to build a replacement Roomba virtual wall with the ATtiny85.

Part 2 - Part 3 - Part 4