INA219 directly on i2c of Pi without ESP8266

[e-sailing]

The code example for python3  openplotter 2.0 is:

Code:

#!/usr/bin/env python3

# This file is part of Openplotter.
# Copyright (C) 2020 by sailoog <https://github.com/sailoog/openplotter>
#                     e-sailing <https://github.com/e-sailing/openplotter>
# Openplotter is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# any later version.
# Openplotter is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Openplotter. If not, see <http://www.gnu.org/licenses/>.

# This tool should receive data from ina219
# convert the data and send it to the signal k server
# You need to install pi-ina219 (sudo pip3 install pi-ina219)

import socket, time, math, csv, datetime, subprocess, sys, os

op_folder = os.path.join(os.path.dirname(os.path.realpath(__file__)), '../..')
sys.path.append(op_folder+'/classes')
from ina219 import INA219
from ina219 import DeviceRangeError

SHUNT_OHMS = 0.1

if len(sys.argv)>1:
    if sys.argv[1]=='settings':
        pass
else:

    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

    poll_interval = 1000

    ina = INA219(SHUNT_OHMS,1.0,1,0x41)
    ina.configure()

    try:
        inaV = ina.voltage()
        inaA = ina.current()/1000
        inaW = inaV*inaA
    except DeviceRangeError as e:
        print(e)
    
    while True:
        time.sleep(poll_interval*1.0/1000.0)

        try:
            inaV = inaV*0.8 +ina.voltage()*0.2
            inaA = inaA*0.8 +ina.current()/1000*0.2
            inaW = inaV*inaA
        except DeviceRangeError as e:
            print(e)

        SignalK = '{"updates": [{"$source": "OPsensors.I2C.ina219","values":[ '
        Erg=''
        Erg += '{"path": "electrical.batteries.rpi.current","value":'+str(inaA)+'},'
        Erg += '{"path": "electrical.batteries.rpi.voltage","value":'+str(inaV)+'},'
        Erg += '{"path": "electrical.batteries.rpi.power","value":'+str(inaW)+'},'            
        SignalK +=Erg[0:-1]+']}]}\n'
        sock.sendto(SignalK.encode(), ('127.0.0.1', 20220))

Please remember we set i2c address to 0x41 because the standard 0x40 could be used by other devices (HTU21D).
And you have to setup a signalk connection on port 20220.

For 1.2:
I think the library has changed. You have to change line 45 /home/pi/.config/openplotter/tools/analog_ina219/analog_ina219.py to

Code:

    ina = INA219(SHUNT_OHMS,1.0,1,0x41)

There is also a chance to read ina219 by node-red (advantage less cpu power consumption)
cd .signalk/red
npm install ina219
git clone https://github.com/easybotics/node-red-c...ina219.git
cd node-red-contrib-easybotics-ina219
npm install
sudo npm link
This link must be moved or copied to .signalk/red/node_modules
cp /usr/lib/node_modules/node-red-contrib-easybotics-ina219-sensor /home/pi/.signalk/red/node_modules

Code:

[{"id":"9dd53318.b65b58","type":"ina-sensor","z":"413e23b8.c0b474","name":"","handle":"cd4c02a9.2f45b","x":510,"y":120,"wires":[["4ac9724a.23dc94"],["f3918cff.9c8ab8"]]},{"id":"5d9fe981.6e7708","type":"signalk-send-pathvalue","z":"413e23b8.c0b474","name":"","source":"","x":1030,"y":120,"wires":[]},{"id":"f3918cff.9c8ab8","type":"function","z":"413e23b8.c0b474","name":"current&power","func":"msg.topic = \"electrical.batteries.rpi.current\";\nmsg.payload = Number(msg.payload)/1000;\nnode.send(msg);\nmsg.topic = \"electrical.batteries.rpi.power\";\nmsg.payload = Number(flow.get('voltage'))*Number(msg.payload);\nreturn msg;","outputs":1,"noerr":0,"x":740,"y":180,"wires":[["5d9fe981.6e7708"]]},{"id":"4ac9724a.23dc94","type":"function","z":"413e23b8.c0b474","name":"voltage","func":"msg.topic = \"electrical.batteries.rpi.voltage\";\nflow.set('voltage', msg.payload);\nreturn msg;","outputs":1,"noerr":0,"x":720,"y":120,"wires":[["5d9fe981.6e7708"]]},{"id":"cd4c02a9.2f45b","type":"ina-sensor-manager","z":"","address":"0x41","delay":"1000","ohms":"0.01","customResistor":false}]