MATERIALS
Resistors: 1kΩ, 2.2kΩ, 3.3kΩ, 4.7kΩ, 10kΩ ( 2), 12kΩ,
22kΩ ( 2), 33kΩ, 39kΩ
78L05 voltage regulator (TO- 92 package) Digi-Key
part #LM78L05ACZNS-ND, digikey.com
Picaxe-08M 8-pin microcontroller SparkFun
Electronics part #COM-08308, sparkfun.com
24-pin IC socket either 10.16mm or 12.7mm wide
(see Step 6); 10.16mm is Digi-Key #A407-ND
9V battery
9V battery clip RadioShack #270-324
Mini speaker removed from a pair of headphones
3.5mm stereo jack Vetco Electronics #PH-504KB,
vetco.net
24-gauge insulated wire, 2'– 3'
1" and 2" heat-shrink tubing, each 3" long
Small cable ties
Picaxe serial programming cable
SparkFun #PGM-08313
TOOLS
Soldering iron and solder
Hot glue gun
Needlenose pliers
Side cutters
Knife
For the Moof Tronic software, circuit diagram
with parts list, and programming instructions,
see makezine.com/15/mooftronic.
1. Fit the 8 resistors to the
IC socket bottom.
The 8 resistors form a ladder of increasing resistance that allows the socket pins to play different
notes. Start the ladder by bending the legs of the
1K resistor around pins 12 and 13, leaving enough
wire on one end to join pin 13 to pin 14. Trim excess
wire and repeat down the socket, joining pin pairs
with the 2.2K, 3.3K, 4.7K, 12K, 22K, 33K, and 39K
resistors, in order (Figure A). No jumper is needed
between pins 20 and 21. Finally, solder the resistors
in place. See makezine.com/15/mooftronic for a
schematic.
2. Add the voltage regulator.
Trim pin 3 of the 78L05 voltage regulator to about
1", then solder it to the red wire of the battery
clip and cover the joint with heat-shrink tubing.
With the 78L05 facing up, bend pins 1 and 2 out at
right angles, pin 1 to the left and pin 2 to the right.
Positioning the regulator flat within the socket,
bend pin 1 around the IC socket’s pin 1 and bend
the regulator’s pin 2 around the socket’s pin 24
A
B
Fig. A: Building the 8-resistor ladder under the
IC socket. Fig. B: The voltage regulator tucked
underneath the socket.
(Figure B). Trim the wires, but don’t solder yet.
3. Wire the link and 10K resistor.
Solder a wire diagonally from pin 1 to pin 20 of
the IC socket. Connect pin 22 to pin 24 with a 10K
resistor. Wrap the legs around the pins, but don’t
solder yet.
4. Add the stylus and antenna.
To make the stylus, strip and tin a 5" length of wire
and fit some heat-shrink over one end, leaving a
bit of metal exposed. Solder the other end to pin 22
on the socket. For the antenna, solder some leftover
wire from a resistor leg to pin 3 of the socket, and
bend it around to the top (Figure C, next page).
5. Add the program port.
Cut three 4" lengths of wire and solder 1 wire each
to socket pins 2, 23, and 24. Cut the wire from pin
2 in half, and solder-splice a 22K resistor in the
middle. Cover the resistor with heat-shrink. Solder
the wire from the 22K resistor to the ring (middle)
contact of the 3.5mm audio jack, solder the pin 24
Make: 71
