--- Bill of Materials ---

                                         Reference
Quantity     Description                Designator(s)
   1     Capacitor, 10pF                 C3
   1     Capacitor, 30pF                 C6
   3     Capacitor, 100pF                C2, C4, C5
   2     Capacitor, 300pF                C8, C10
   1     Capacitor, 330pF                C7
   1     Capacitor, 500pF                C11
   2     Capacitor, 1µF                  C1, C9
   5     Diode, 1N4148                   D1, D2, D3, D5, D6
   1     Diode, IR Transmitter           D4
   1     PIN photo diode, e.g., BPV23NFL D8
   4     Transistor, 2N3904              Q1, Q2, Q3, Q4
   1     Resistor, 249                   R15
   1     Resistor, 2K                    R4  
   2     Resistor, 4.99K                 R6, R22      
   3     Resistor, 10K                   R3, R16, R19
   3     Resistor, 24.9K                 R2, R9, R14
   1     Resistor, 90.9K                 R1
   1     Resistor, 121K                  R21    
   2     Resistor, 162K                  R5, R13
   1     Resistor, 221K                  R18
   3     Resistor, 249K                  R7, R12, R20
   1     Resistor, 499K                  R17
   3     Resistor, 1.1Meg                R8, R10, R11
   1     LT1018                          U1