MIM.TXT The Micro-Interface-Module (MIM) =========================================================================== Document version: 8.3.8 Document dated: 27 Mar 99 Author(s): Bob Bruninga, WB4APR ABSTRACT MIM.TXT: Using the Micro Interface Module (MIM) for APRS all kinds of APRS low power and compact applications. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ See TELEMTRY.txt for how the MIM telemetry system works See Mic-E.txt for how the MIM chip is used in the APRS Mic-Encoder See Mic-Lite.txt for how to make the MIM into a simple Mic-E The MIM module is a complete telemetry TNC transmitter in under 1 cubic inch! It has a serial data port, 5 analog and 8 digital telemetry inputs. It outputs PTT and transmit audio AX.25 tones. The MIM was developed by Dr. Carl Wick, N3MIM, as a simple, light-weight, throw-away module for experimental balloons. WB4APR modified it for Mic-E operation and Dr. Will Clement refined it into a commercial product. It is now sold by APRS Engineering LLC at the address below. The only external components besides the sensors themselves, are a transmitter and optional GPS and battery. APPLICATIONS: 1) Mobile stand alone tracker with front panel controls 2) Balloon payloads using only party balloons (not big ones) 3) Tracking wildlife or packages 4) Model Aircraft 5) Keeping track of your kids. (Even without GPS, the APRSdos vicinity tracking capablity will tell you if he is near a digipeater. And you can install short range digi's near school or home. MODULE INPUTS INTERFACES ___________ Analog 1 --O| |O--> PTT to XMTR Analog 2 --O| |O--> AX.25 Audio to XMTR Analog 3 --O| |O Analog 4 --O| M.I.M |O<-- GPS data Analog 5 --O| |O<-- RCV Audio Input bit 1 --O| Telemetry |O input bit 2 --O| |O input bit 3 --O| Module |O input bit 4 --O| |O input bit 5 --O| |O input bit 6 --O| |O<-- 7 to 16 volts input input bit 7 --O| |O input bit 8 --O| |O<-- Ground ------------- MIM PACKETS: The mim can operate in either MIM mode or MIC mode. Here are the packets in each mode: MIM MODE: STATUS packet transmitted every N seconds POSIT packet transmitted every P seconds TELMETRY packet transmitted every T seconds CWID transmitted every C seconds Mic MODE: POSIT packet every P seconds STATUS text apppended to posit every P/S seconds TELM telemetry appended every P/T seconds MIM TELEMETRY: See the full telemetry spec in TELMTRY.txt. The on-air packet telemetry format is as follows: T#sss,111,222,333,444,555,xxxxxxxx where sss is the serial number followed by the five 3 digit analog values and the eight binary values. CAUTION: The MIM inputs and outputs are unprotected and assume your circuits are protected against transients above +5 and below 0 volts. For this analog voltage input, a 5v zener diode should be used on A0 for protection. ORDERING YOUR MIM: Price is $79 plus $4 S&H or $69ea for 10 or more. APRS Engineering LLC (Sorry, can't do credit cards) 115 Old Farm Ct (Phone voice mail 410-553-6021) Glen Burnie MD, 21060