APRS TELEMETRY

The APRS on-the-air protocol (see my APRS page) also allows for a wide range of telemetry experiments. I am using a 68HC11 based microcontroller system (LEMPS) to carry out some telemetry experiments. The present idea is to use it as a remote weather station by adding various additional sensors (pressure, humidity, etc.). Telemetry data are transmitted as AX.25 packets in the 144 MHz amateur radio 2-meter band using the APRS digipeater network.

Below you can have a closer look at the telemetry system itself and at a telemetry recording.

Data recorded by the LEMPS weather station can be reviewed here.

The microcontroller system is housed in a suitcase. For a larger version and details click picture.	The last transmitted telemetry values are displayed on the LCD. For a larger version click picture.
A variety of sensors can be attached to the system. This is a photovoltaic cell used for light measurements. For a larger version click picture.	A Kenwood TH-D7E is used as a terminal node controller (TNC). For a larger version click picture.

 

 This plot shows light intensity and temperature (°Celsius) recorded in Zauggenried (JN37SB) on August 20th, 1999.

The "noise" on the light intensity (blue) corresponds to clouds briefly hiding the sun.

Ernst Niggli's Home Page

Ernst Niggli's Group Page

HB9PVI APRS Page

These on-the-air packets are then analyzed by MacAPRS software and an example is shown below.