The following parts are needed if you use the Olimex board as a starting place
I believe this is finally correct. You may only need two of the 0.1 uf bypass caps but they are cheap so I recommend we be safe and add one to the 16F88.
|1||Olimex Board||Prototype board (16F88 20 Mhz)|
|3||0.1 uf||C3, C6, C7 - Monolithic capacitors|
|2||1N4148||D3, D4- Signal diodes|
|1||color LED||D1 - Receive data indicator|
|1||color LED||D5 - Transmit data indicator|
|4||1k||R1, R5, R8, R11 - resistors|
|2||2k||R9 - resistor|
|1||3.9k||R3 - resistor|
|1||8.2k||R4 - resistor|
|1 or 2*||100k||R6 - resistor|
|1 or 2*||470||R10 - resistor|
|1||10K variable||R12 - miniature potentiometer|
|1||2N2222A||Q1 - PNP transistor|
* There is a suggested addition to Bob's original circuit that would add another 100K and a 470 ohm resistor. They add a little hystereses to the input comparator circuit. I recommend these changes and will add them to my unit but they are not required. I will describe how the additional resistors are wired into the circuit an a few days.