Abstract
This program is able to calculate the position of moving targets (i.e. moon, sun,
cosmic noise sources) and follow them. It is also possible to get azimuth and
elevation data from a Tracking Server (i.e.
WinOrbit). To read the azimuth
and elevation angle, the mechanical parts of a computer mouse and its interface
are used. The steering of the rotors will be done via the parallel interface.
That is with a Microsoft-Mode 2 mouse, two ICs and 4 relays you can realize a
lowcost autotracking system.
Function
After loading RotorSys32, the program needs to be calibrated at the reference
positions, which should be set close to the parking headings, in order to shorten
the calibration procedure. A blue AZ/EL-angel indication marks the reference position.
The azimuth reference is reported by the left mouse key, the elevation reference
by the right one. As long as the azimuth and elevation reference marks are not
found, the autotracking is disabled. After entering the proper position or
locator and selecting the object to follow the tracking may be started. An
existing offset in azimuth or elevation may be corrected using Config/Offset/
AZ-Offset or EL-Offset. If the calculated elevation is negative, the rotaries
won´t be activated.
Configuration
A number of parameters may be defined in the Config-menue and saved in a standard
Windows-format .INI (initialization) files.
- Config/COM-Port = where the mouse encoder is connected Com1...Com4.
- Config/LPT-Port = where the rotor interface is connected LPT1...LPT2.
- Config/Decoder/AZ-P/360 = number of azimuth-pulses over 360 degree.
- Config/Decoder/El-P/360 = number of elevation-pulses over 360 degree.
- Config/Reference/AZ-Ref. = AZ-angel, on which the sensor is activ (left
mouse button).
- Config/Reference/EL-Ref. = EL-angel, on which the sensor is activ (right
mouse button).
- Config/Precision/AZ-Prec. = tolerance of the azimuth-tracking [0..10°]
(depends on the play in drive and the speed of rotation).
- Config/Precision/EL-Prec. = tolerance of the elevation-tracking [0..10°]
(depends on the play in drive and the speed of rotation).
- Config/Offset/AZ-Offset = corrects an eventualy existing
offset-azimuth-angle [+/-10°].
- Config/Offset/EL-Offset = corrects an eventually existing
offset-elevation-angle [+/-10°].
- Config/QTH/Latitude = geografical latitude (+ = north, - = south).
- Config/QTH/Longitude = geografical longitude (+ = west, - = east).
- Config/QTH/Locator = own locator, (latitude and longitude will be calculated).
- Config/Park/AZ-Parkpos. = azimuth parking position of the antenna.
- Config/Park/EL-Parkpos. = elevation parking position of the antenna.
Interface
The rotaries are controlled via the data lines of the parallel port (active high).
Pin2 = AZ-rotary moves clockwise
Pin3 = AZ-rotary moves counter clockwise
Pin4 = EL-rotary moves up
Pin5 = EL-rotary moves down
Pin6 = AZ-rotary moves fast (if in the tracking mode the target offset > 10°
this pin is H)
Pin7 = EL-rotary moves fast (if in the tracking mode the target offset > 10°
this pin is H)
Pin25 = ground
Interface circuit.
Adaption of the encoders
This part of the work needs a bit of subtle intuition since there are different
ways of encoder mechanics used in a mouse. Of special interest are those with
two physically separated encoders. In principle, they must be demounted from the
circuit board of the mouse and attached to the axis of the rotary. The same applies
to the two reference sensors. This task has to be solved individually, of course.
Additionally, so far the necessary experience is missing to provide a patented
recipe. The tests were carried out using a Genius mouse, in which encoder wheels
with 45 slits are mounted. With this wheels, a resolution of 360°/45*4 = 2° is
achieved.
The mouse electronics evaluates the signals coming from
the opto couplers. It can recognize even a quarter of a period, since the opto
coupler are mounted at 90° to each other. Also a professional incremental encoder
(1250 pulses per 360°) was tested after connecting it to the mouse electronics
(resolution = 0.072°). This, of course, is the best solution, but also a bit
more expensive. It should be noted, that rotary speed must be decreased with
rising pulse rate.
Final note
With this program the author tried to find an inexpensive solution for the
Antenna autotracking problem. Of course, this system can be improved. This
should be a stimulus for further experiments to replace the existing analog
system by a digital one.
Please note that RotorSys32 is still under test, any hint about mistakes or new
ideas are welcome.
Mouse electronics with demounted encoder and sensors,
behind you see an professional encoder (1250 pulses/360°).
Download RotorSys32 (314kB) for Windows 95, 98,
Me. Last update 15.01.05.
Download ObjData (250kB) This program calculate the position of the sun, moon and cosmic noise sources.
Please note that if you use Rotorsys32 on Windows 2000, XP or NT you will need a kernel
driver that gives usermode programs access to I/O Ports.