Direction indicator for HF antenna using LED chip WS2812 and magnetic sensor AS5600
Last update February 23, 2020
In our club we need an angle indicator to display azimuth of our new antenna. I decided to
use some new smart components that make it simple.
LED circle - the direction is shown using circle of 48 RGB LEDs WS2812. You can find description on the web, so just
shortly. It needs a 5V supply, the data go to LED as serial data stream. First LED keeps own data and passes other data
to next LED in chain etc. Advantage - only one wire can control all LEDs, no need to separate wire to each LED.
Sensor - uses IC magnetic sensor AS5600. It is sold as a module, including magnet. The IC offers lot of configuration
possibilities, I use analog output 0.5 to 4.5V (by 5V supply) for angle range 0 to 360 degs. Sensor is configured
via I2C bus, configuration is burned in it so the I2C bus is later not needed.
Controller - I use AtTiny13 with internal 9.6 MHz clock. It has 2 ADC channels - one for sensor signal and
the other for trimmer giving offset signal (you can compensate zero position of sensor). Additionally there is a
jumper that reverse the rotation sense. PCB design is not the best (AtTiny is up end down :-) but I suppose nobody
will make a copy, at least because of not standard stabilisers used. Firmware is written in assembler (the code
that transfers data to circle is time critical), but it is relatively simple. As usual on my web, see bellow for open source code.
Interface - to be mounted close to sensor module. Contains 5V stabiliser, amplifier with factor 2, giving
output voltage 1V to 9V, plus ESD protection (the antenna tower can be hit by lightning!)
Note: the controller with the LED ring can be connected to other sensors (like potentiometer used in most rotators),
it is not specifically designed for AS5600 sensor. The source code can be modified for other LED circles with
different LED count - just try it!
Files:
Complete archive containing datasheets of important components, Arduino application used to program the sensor
over I2C bus, circuit diagrams and PCB layout for KiCad, source code and compiled hex code (flash only, EEPROM
is not used). I appolgize some documents are in Czech (intended to our club members).
73 OK1DX