ID-O-Matic Manual
6/16/2004
Page 5 of 5
a small piezo speaker or using a small transistor amplifier. More elaborate solutions might include an audio amplifier such as
an LM386 with filtering to "round off" the square wave to produce a more comfortable tone.
Keying a transmitter:
In general, avoid any voltage exceeding the supply voltage Vdd on any I/O pin, and limit current to less than 20 mA. Keying
for most solid state, positive-keyed transmitters and transceivers is simple and requires only a single transistor or MOSFET.
Small signal MOSFETs such as the recommended 2N7000 can generally be driven directly from the output pin of the PIC. If
you intend to use the ID-O-Matic with a rig requiring grid-block or cathode keying, you will need to add a grid-block keying
adapter such as the Universal Keying Adapter.
Support:
Should you need support, have questions, have feature requests or bug/problem reports, please feel free to contact me via email
at [email protected] or [email protected]. I will make every effort to respond as quickly as possible.
Warranty:
All parts are tested and are guaranteed against defects for 90 days from date of purc hase. This warranty does not cover damage
due to incorrect assembly, improper soldering or wiring, overvoltage, static damage or other misuse or abuse. If you have
problems, please contact me via email to arrange for an exchange or replacement part. If you accidentally damage a part, don’t
panic – just contact me, replacements are not expensive. Unfortunately I cannot offer assembly or repair service, but you
should be able to find someone local to help out in the event of problems with assembly.
NOTE: Complete electrical specifications for the PIC16F628A can be found on Microchip’s web site at
http://www.microchip.com/.
Schematic of ID-O-Matic Kit:
