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 voltMicrophones (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
Replace LED/Resistor with the rest of the circuit.
Switch is the 4th contact on headphone jack.
All About Circuits article on MOSFETS