The Low Cost Telemetry Device (LTD) provides a low cost, minimal parts count Telemetry keyer using an Atmel’s ATMega8 Microcontroller. The LTD sends data by measuring voltage levels of up to four analog channels via its on-chip 10-bit Analog to Digital Converter (ADC) and converting them to numbers and sending the measurements via Morse Code. There are two signal outputs – one is a binary Morse Code signal such as would be used to key a Continuous wave (CW) transmitter, and the other output is tone modulated and could be used to drive a small speaker to the audio input of a transmitter.
Options allow setting code speed to 25, 10, 5 or 1 word per minute, 1 kHz or 500 Hz tone, and measuring 1, 2, 3, or 4 analog channels. The options maybe set with jumpers or with and EIA-232 terminal, and in the case of setting it up with a terminal, a text string of up to 80 characters maybe sent along with the data. Terminal settings are 9600 Baud, no parity.
The controller firmware contains routines to scan from one to four 10-bit analog input channels and send the measurements by Morse Code as determined by either jumper settings, or parameters set with a serial terminal and the parameters stored in the chip’s internal EEPROM. The Low-Cost Telemetry Device is designed by Dick Cappels and Jeff Heidbrier.
Project Detail and Documentation