Project Design

Schematics and Part Lists

Control Board

(From headwize.com)

Note: This circuit has been replaced with a modified design.

Parts List

Resistors (1/4W, 1% metal film):
R1 - 4.7Kohm
R2, R3 - 2.2Kohm
R4, R5 - 1M
R6, R7 - 1Kohm
R8, R9 - 33Kohm
R10-13, R15-18 - 10Kohm
R14, R23 - 100Kohm pot, dual-gang, linear taper
R19, R20 - 100Kohm
R21, R22 - 47 ohm

Additional Parts and Materials:

IC1-3 - NE5532 dual audio op-amp
C1 - 33uF, 25WVDC, electrolytic capacitor
C2, C3 - 0.01uF Mylar capacitor
C4, C5 - 10uF, 25 WVDC, electrolytic capacitor
J1-3 - Audio jacks, 1/8-inch, stereo
S1, S2 - Dpdt toggle switch
B1, B2 - Battery, 9 volt
Microphones (Digi-Key P9967-ND or similar), headphones, PC board, case, wire, hardware, etc.
Microphone: Jameco Part # 160979CH
IC1-2 - TS912N
IC3 Replacement: LM386

Charger Board

Identical design as TekBot charger board

Schematic (ECE112 lab manual appendix)
Assembly instructions (ECE112 lab manual)

MOSFET power control

Using a MOSFET as a switch

Replace LED/Resistor with the rest of the circuit.
Switch is the 4th contact on headphone jack.

All About Circuits article on MOSFETS

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