IAMBIC KEYER



 

COMPONENT VALUE
R1,R2 100K
R3,R4,R5,R6 5K1
R7 1K2
C1,C2 0.01 mFd
C3 470 pF
C4 47 mFd
ZD 5V1
T1 BC547
IC1 PIC16F84 OR PIC16C84
D1 1N4007
P1 22K

This iambic keyer uses a PIC16C84 or PIC16F84 microcontroller to generate the dot/dash timing and key the transmitter. Most modern rigs are keyed by grounding the key line. The maximum current on the keying line is usually no more than a few mA. If your transmitter has high voltage or high current on the keying line, you will need to use a relay to key the rig (see circuit below.)


You can download the pic program source code here: iambic.asm
PIC16F627 and PIC16F628 code here: iambic-62x.zip See below.





IAMBIC KEYER PCB.



IAMBIC KEYER PCB LAYOUT (GIF)


Download PCB layout as a Postscript file: key_pcb.zip



KEYER COMPONENT OVERLAY (VIEW FROM COMPONENT SIDE)



USING A RELAY TO KEY THE TRANSMITTER




FINISHED PCB



Sept 2009. The circuit was modified to work with the PIC16F627 and PIC16F628. Note that the PIC16C84 RC oscillator has been replaced by the ER (external resistor) oscillator configuration of the PIC16F62x. The hardware modifications are shown below. Source code and HEX files are available above. This configuration has been tested with the PIC16F627 and PIC16F628. The chips I used were -04/P types (4MHz/DIP). It will almost certainly work with other 62x variants like the PIC16F628A.



Modified hardware for PIC16F627/PIC16F628



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