Page 394 - Hacking Roomba

Chapter 16 — Other Projects 375

Warranty-Voiding Hacks

This book has purposefully steered away from projects that definitely void the warranty of your
Roomba. Interfacing through the ROI probably doesn’t void the warranty, but the following
hacks definitely do.
If the following hacks interest you, you should get a second Roomba to do them on. These hacks
can destroy a Roomba, and you don’t want to take your nice, expensive Roomba and void its
warranty. You can find older used Roomba models on eBay. And factory-refurbished ones with a
significant discount can be found on Amazon.com and other retailers on the Internet.

Line-Following Roomba

http://www.northridgerepair.com/plog/

Ben Miller discovered a way to turn the four cliff sensors on the front of Roomba into line sen-
sors. He found that by placing a calibrated resistance across the photodiode of a cliff sensor, he
could make the cliff sensor differentiate between carpet and black tape. Figure 16-12 shows the
essence of his hack. The resistors are attached across the photodiode part of the cliff sensor and
can be made reversible so you get normal functionality back.
Each sensor has to be calibrated by tuning the variable resistor until it triggers when it passes
over the tape. Then, by programming the robot through the ROI (Ben used a Basic Stamp),
you can poll the cliff sensors and watch for when Roomba crosses the black line.

100 100
Added circuitry

Sensor photodiode Original Roomba circuitry
FIGURE 16-12: Schematic of added components to each cliff sensor

Vacuum Motor Connector Hacking

The vacuum motor of Roomba exists in the removable dustbin. This means power must be
routed to that motor and if you remove the dustbin and look at the right side of Roomba, you’ll
notice two electrical connectors (see Figure 16-13). This connector provides power directly
from the Roomba battery but switched through the vacuum motor bit in the ROI MOTORS