Servo power 6V
Picaxe power
4.5V to 5V
3.5mm stereo
jack (used with
USB download
cable)
Servo
SerialIn
Gnd
Serial-Out
Caution!
Don’t mix up
these wires!
WARNING:
Double- and triple-check
the wiring before applying
power, and make sure
the power connections
aren’t reversed, or else
permanent damage can
result to the Picaxe, the
capacitors, and the
servo. Reversing the
voltage to the servo
can cause its nearly
instant (and sometimes
explosive) death!
H
Front
1
2
3
Vishay
TSOP38238
IR module
(or equivalent)
123
4.5V to 5V
+ – 6V battery
pack
4.7kΩ
330Ω
Picaxe 08M
3
1
Out1
Out4
330Ω
54
In3
8
LED
1
2
Signal
+
–
47μF
Servo
3
4.7μF
I
08M has built-in commands for reading and
decoding Sony SIRC protocol IR codes.
4. Program the Picaxe.
Download and install the free Picaxe Program
Editor (Windows) or AXEpad (Mac/Linux)
software from picaxe.co.uk. Plug your programming cable between your computer’s
USB and the 3.5mm jack.
Launch the Program Editor or AXEpad, and
specify 08M under Options → Target Device.
Also select the serial port used with the
download cable.
Download the project code from make
projects.com/v/27 and open it in the editor.
Apply power to the microcontroller circuit
only — the servo doesn’t need to be powered
yet — and click the Program button to compile and transfer the code to your Picaxe.
should glow to indicate when the Picaxe is
sending pulses to the R/C servo, and the servo
should quickly center itself.
Point the remote at the IR receiver on the
breadboard and start pressing buttons to
control the servo actions as follows:
» Channel Up/Channel Down — close/open
the gripper incrementally.
» 2/8 — close/open the gripper fully.
» 5 — set the gripper to midway.
» 0 — toggle the servomotor power on and
off (to extend battery life).
The gripper should be closed, or nearly so,
when the servo is rotated all the way clockwise. To adjust its range, unscrew the servo
horn from the servo’s motor shaft, reposition
it, and put the screw back on.
The 0 button toggles “active” mode. Press
it once (the LED goes out), and the servo
shuts off after each move, saving power and
eliminating a slight jitter. Press 0 again (the
LED goes on), and the servo receives periodic
pulses to set its position, which makes it
maintain a tighter grip on things.
Comments in the code explain how to
change parameters to fine-tune your Teleclaw.
That’s it! It’s just that simple. In the next
installment of Telerobots for World Domination,
I’ll tackle the job of creating a weapons system
consisting of a pulsed atomic-powered rail gun
and chemical laser. Stay tuned, fellow space
explorers!
5. Now play!
Connect power to the servo, then disconnect
and reconnect power to the Picaxe. The LED
Gordon McComb, “the father of hobby robotics,” has been
building robots since the 1970s, and wrote the bestselling
Robot Builder’s Bonanza. Read his plans to take over the world
with an army of mind-controlled automatons at robotoid.com.
65 Follow us @make
