Originally, I used a universal TV remote. For the second
bot, I decided to completely redesign the remote control. I
used one of the Kronos Robotics motor switch boxes, as
shown in Figure 9. These control boxes have four, three-state
I used the Athena microcontroller to create an interface
to the switch and to send the IR data. The Athena has
built-in IR transmitter and receiver commands. All you have
to do is connect an IR LED to port 6 and you can start
transmitting IR codes.
I used the Athena Carrier 1 board for the IR transmitter
with a couple of headers. The board is mounted on the four
AA cell battery holder (Figure 10). If you lose control of the
bot, simply poke a small, 1/4” small hole in the duct and
insert the transmit LED to regain control.
A 2N2222 transistor is used to drive the IR LED for more
power. If you use a transistor other than the one listed, you
may need to place a 1K-10K resistor between the I/O port 6
of the Athena and the base of the transistor.
The Athena program monitors the four switches on the
motor switch. Every 25 ms, a code is sent to the duct bot
with instructions on the state of each switch, as shown in the
‘motor switch controller for duct bot
swno=1 : gosub check1
swno=2 : gosub check2
swno=3 : gosub check3
swno=4 : gosub check4
Figure 7 — Front of the
decked out crawler.
Figure 9 — The robot control box.
12 SERVO 07.2004
Figure 8 — Notice the large Tx
antenna for the camera.
Figure 10 — The Athena carrier
on the battery pack.