avnav-anchor-chain-counter-rpi-gpio

read the pulses from reed relais on anchor winch via Raspberry PI's GPIO

General

The plugin reads pulses from a read relais on the anchor winch. Addtionally it need the Up/Down information anchor winch relais.

It is widely based on the

• seatalk remote plugin (https://github.com/wellenvogel/avnav-seatalk-remote-plugin),
• more nmea plugin (https://github.com/kdschmidt1/avnav-more-nmea-plugin) and
• Seatalk1 to NMEA 0183 (https://github.com/MatsA/seatalk1-to-NMEA0183/blob/master/STALK_read.py).

Parameter

• circumference: circumference of anchor winch
• gpio_reed: Define gpio where reed relais is sensed (default is 17 => GPI17 on pin 11)
• gpio_up: Define gpio where the up is sensed (default is 27 => GPI27 on pin 13)
• gpio_down: Define gpio where the up is sensed (default is 22 => GPI22 on pin 15)
• inverted: Define if input signal shall be inverted 0 => not inverted, 1 => Inverted (default is 1)
• pulldown: Define if using internal RPi pull up/down 0 => No, 1= Pull down, 2=Pull up (default is 2)

Details

Hardware needs

It is strongly commended to use optocoupler between seatalk 1 level and Raspberry Pi inputs.

An example for such an circuit is suggested here: https://pysselilivet.blogspot.com/2020/06/seatalk1-to-nmea-0183-converter-diy.html

First tests are made with th module BUCCK_817_4_V1.0.

The reed relais is a brought one:

All is connected via a 5-pin-socket

Software installation

To install this plugin please

• install packages via: sudo apt-get update && sudo apt-get install pigpio python-pigpio python3-pigpio
• start pigpio deamon e.g. via sudo servive pigdiod restart
• create directory '/usr/lib/avnav/plugins/avnav-anchor-chain-counter-rpi-gpio' and
• and copy the file plugin.py to this directory.

Using in anvav

TODOs

• reading GPIO in interrupt mode doesn't work => currently poll mode is implemented with 10 ms