picmd example

README.md

picmd example

Host (Raspberry PI) Side

Install

Deploy app.py and requirements.txt to Raspbian.

Login to Raspbian and set up the Python environment (You need python3-venv to use venv).

$ python3 -m venv venv
$ source venv/bin/activate
$ pip install -r requirements.txt

Enable serial communication in raspi-config.

Launch

Run the app.py script under the venv environment.

(venv) $ python app.py

Client (PC) Side

Install

Deploy app.js and package.json to PC.

Install node-picmd using npm.

$ npm install

Launch

Run the app.js.

$ node app.js

app.js

const { PiCmd } = require('@ushiboy/picmd');

(async function() {
  const pic = PiCmd.connect('/dev/ttyUSB0')

  const r1 = await pic.request(0x01, Buffer.from('world'));
  console.log(r1.value.toString('utf-8'));

  const r2 = await pic.request(0x02);
  console.log(r2.value.readDoubleLE(0))

}())

app.py

import re
import subprocess
from picmd import PiCmd

app = PiCmd.create('/dev/serial0')

@app.handler(0x01)
def greeting(data: bytes) -> str:
    return 'hello %s' % data.decode('utf-8')

@app.handler(0x02)
def measure_temp():
    r = subprocess.run(['vcgencmd', 'measure_temp'], capture_output=True)
    d = r.stdout.decode('utf-8')
    m = re.match(r"^temp=([\d\.]*)'C", d)
    return float(m.group(1))

app.run()

package.json

{
  "name": "picmd-example",
  "version": "0.1.0",
  "description": "picmd client example",
  "main": "app.js",
  "author": "ushiboy",
  "license": "MIT",
  "dependencies": {
    "@ushiboy/picmd": "^0.1.1"
  }
}

requirements.txt

picmd==0.7.0