If you are using the PIC12f675 you can improve the performance of your BLF bot by performing calibration.
Due to differences in the brushes and motors the bots tend towards circling around, rather than going in a straight line. Calibration evens up these differences.
If you are not using the PIC12F675 then doing this step may damage a port on your uP
To calibrate the bot you will need to download and print the BLF calibration sheet.
To enable the Learn mode bring up the SL4 LED line high when powering on the bot. Remove the high on the led as soon as the bot starts. This will immediately start the bot in Learn mode.
Place the bot on the sheet and let it run a couple of times to the edge of the sheet.
Restarting the bot will restore the normal operation, but with the new calibrated settings.
If you need to restore the bot to its non-calibrated state, Repeat the above instructions, but rather than letting the bot run over the sheet switch if off and remove the high on the led without running it over the calibration sheet.