I2c on OrangePi Zero

Hardware
1

Hi all.
I'm new .
On my OrangePi Zero install OLED LCD.
if list all device on my i2c bus show this :

i2cdetect -y 0
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- 3c -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

OrangePi_i2c

I install node-red-contrib-i2c
how I can list all devices on my i2c bus??
some example pls ..
my bus is used 0 not 1

thanks

2

i2c

[{"id":"a296b2f6.143b6","type":"inject","z":"95f61204.15452","name":"","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":624,"y":600,"wires":[["f57e2b0c.6cf508"]]},{"id":"f57e2b0c.6cf508","type":"i2c scan","z":"95f61204.15452","x":756,"y":600,"wires":[["869fbda3.677f4"],["502204e0.c7244c"]]},{"id":"869fbda3.677f4","type":"debug","z":"95f61204.15452","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":914,"y":576,"wires":[]},{"id":"502204e0.c7244c","type":"debug","z":"95f61204.15452","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":914,"y":612,"wires":[]}]
3

this is result :
i2c_scan

then on what bus search ?? 0 , 1 , or 2 ??

4

you need bus 1 per node-red-contrib-i2c 0.5.2
"Downside my nodes work only for newer version where the i2c driver is on /dev/i2c-1"

This is something i still need to try, I2C For Everyone
maybe this could help

5

hi.
Orange Pi zero have two TWI port , 0 and 1 .
My LCD is connected to 0 , but if connect to 1 and test node-red then work..
will be good if user can select want port want use ..I can redefine .. my code for LCD for port 1 .. but still will be good if user can select what bus want use ..

regards.

6

I have just tested -
"This is something i still need to try, I2C For Everyone"
and it works, So there is you solution it will work on both busses

Let me explain;
cd ~/.node-red/
npm install i2c-bus
node-red-stop
sudo nano ~/.node-red/settings.js
functionGlobalContext: {
// os:require('os'),
// jfive:require("johnny-five"),
// j5board:require("johnny-five").Board({repl:false})
//underscore:require('underscore'),
i2c:require('i2c-bus'),
},
cntr o
enter
cntr x
enter
node-red-start

var i2c=global.get('i2c');
i2c1 = i2c.openSync(0);

node.warn(as())
function as() {
var info = i2c1.readByteSync(3c, 255);
i2c1.closeSync();
return info;
}
7

Hi. I do it ..
try function but not response from bus .. return info not see on debug ..
I'm new nad don't good understand how node-red work ..then sorry..

8

The example i used is to read a chip in this case a pcf8574,

I think you need to write data to the oled screen, not read data from it.
maybe this can help you Display temp (18b20) on oled with just pi and nodered

9

Don’t run this line with sudo, a normal nano ~/.node-red/settings.js is fine. By editing as sudo, the file becomes owned by root after saving, meaning node-red running as the current user (as ~/.node-red suggests) might have trouble reading it, thus leading to running node-red as root too to get around. Just don’t use sudo here.

10

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