skywriter - python to javascript

[kclemen]

Just bought a skywriter to control my mirror based on swipes and presses. (https://shop.pimoroni.com/products/skywriter-hat)

It comes with a python library: https://github.com/pimoroni/skywriter-hat

What I would like to achieve is that a certain div comes to the page when I make a “up” gesture. Or when I swipe left, that the entire page is switched to another profile.

What is the best starting point to control javascript in a webpage thru python?

[Jopyth]

@kclemen If you want an example of how to put together python and a module, you can have a look at this. It uses a python backend for face recognition. I think you could use a similar approach to “listen” for flicks.

[kclemen]

Thanks for your reply. First glance at the link, seems to be rather difficult to implement what I want.

Following code can be generated in py to link an action to a certain “gesture”:
if(start == “north” and finish == “south”):
print “Volume: down”
system(“irsend SEND_ONCE TV KEY_VOLUMEDOWN”)
elif(start == “south” and finish == “north”):
print “Volume: up”
system(“irsend SEND_ONCE TV KEY_VOLUMEUP”)

I would like to slde in a certain dev when I wave from “north” to “south”… Searches on the net results that py and javascript do not work ery well together?

[Jopyth]

@kclemen Well, you can try googling for node.js (which is programmed in javascript) and python, and the answer will be quite different.

If you want to program this module, you will need (at least) 3 components (I will demonstrate how it works in the facial recognition example):

• the module in the browser:
  this will listen for events send from node_helper.js, for example see this function. In the example, it broadcasts this event to all modules (here), and then catches that notification again (here) to show all modules with a certain class

• the node_helper.js:
  this is what will be calling your python code in the backend, for example in this line the python module is started, and then listens for events here

• your python code:
  not much here you need, most of the code would look like your example, except the communication to node from this line

Hope this helps to get you started.

[kclemen]

@Jopyth Thanks for your wonderful reply. Will take a look at it as soon the skywriter is delivered.

[kclemen]

ok, first steps are being taken… https://github.com/Kclemen/MMskywriter

[kclemen]

fixed it…

[kclemen]

I’ve got following error:

SyntaxError: Unexpected token g in JSON at position 0
at PythonShell.asJson (/home/pi/MagicMirror/modules/MMM-skywriter/node_modules/python-shell/index.js:142:21)
at /home/pi/MagicMirror/modules/MMM-skywriter/node_modules/python-shell/index.js:232:35
at Array.forEach (native)
at PythonShell.receive (/home/pi/MagicMirror/modules/MMM-skywriter/node_modules/python-shell/index.js:231:11)
at emitOne (events.js:96:13)
at Socket.emit (events.js:188:7)
at readableAddChunk (_stream_readable.js:176:18)
at Socket.Readable.push (_stream_readable.js:134:10)
at Pipe.onread (net.js:543:20)

Here is the script:
`#!/usr/bin/env python
import sys
import json
import time
import signal
import skywriter

some_value = 5000

last_airwheel = 0
delay = 5000

def to_node(type, message):
# convert to json and print (node helper will read from stdout)
try:
print(json.dumps({type: message}))
except Exception:
pass
# stdout has to be flushed manually to prevent delays in the node helper communication
sys.stdout.flush()

to_node(“status”, ‘Skywriter started…’)

@skywriter.flick()
def flick(start,finish):

#slide music player div OFF the screen
if(start == "north" and finish == "south"):
	print "gesture is north to south"
	to_node("gesture", "down")

#slide music player div ONTO the screen
elif(start == "south" and finish == "north"):
	print "gesture is south to north"
	to_node("gesture", "up")

#Next track
elif(start == "west" and finish == "east"):
	print "Gesture is west to east"
	to_node("gesture", "next")

#previous track
elif(start == "east" and finish == "west"):
	print "Gesture is east to west"
	to_node("gesture", "previous")

#else:
	# print "Invalid"

@skywriter.airwheel()
def spinny(delta):
global some_value
global last_airwheel
global delay
some_value += delta
if some_value < 0:
some_value = 0
if some_value > 10000:
some_value = 10000
now = int(round(time.time() * 1000))
if(now - last_airwheel > delay):
print(“TV & Digibox: power”)
# system(“irsend SEND_ONCE TV KEY_POWER”)
# system(“irsend SEND_ONCE Digibox KEY_POWER”)
last_airwheel = now

signal.pause()`

I do not really understand what is wrong? Anybody an idea?

[Jopyth]

@kclemen Please use three backticks (```) for markdown if you paste your code, instead of one (`). Otherwise it will not recognize it as multi line code.

The problem are your regular print statements (e.g. print "Gesture is west to east"), these are also read by node, and they are not in the JSON format. You can comment these out, or maybe write them to a log file instead, if you want them to debug.

[kclemen]

Thanks for the input. Indeed this was the mistake.

seems I’m missing still something. Now I get following error:

TypeError: parser.close is not a function
at SAXStream.openf1 (/home/pi/MagicMirror/node_modules/feedme/lib/xmlfeedparser.js:107:14)
at emitOne (events.js:96:13)
at SAXStream.emit (events.js:188:7)
at Object.me._parser.(anonymous function) [as onopentag] (/home/pi/MagicMirror/node_modules/sax/lib/sax.js:258:17)
at emit (/home/pi/MagicMirror/node_modules/sax/lib/sax.js:640:35)
at emitNode (/home/pi/MagicMirror/node_modules/sax/lib/sax.js:645:5)
at openTag (/home/pi/MagicMirror/node_modules/sax/lib/sax.js:841:5)
at Object.write (/home/pi/MagicMirror/node_modules/sax/lib/sax.js:1404:13)
at SAXStream.write (/home/pi/MagicMirror/node_modules/sax/lib/sax.js:239:18)
at yoshi.write (/home/pi/MagicMirror/node_modules/feedme/lib/feedme.js:41:14)

[kclemen]

Ok, the script is performing without any errors at the moment.

Would somebody be so kind to check why console.log(“payload.action is up”); is not executed in MMM-skywriter.js?

I only get the message from node-helper.js : console.log(“[” + self.name + "] " + message.gesture);

Files can be found here: https://github.com/Kclemen/MMM-skywriter

[kclemen]

Node helper:
self.sendSocketNotification('gesture', message.gesture);

script:

Module.register("MMM-skywriter",{
	
	//	gesture_up: 0,
	//	gesture_right: 0,	

	// Override socket notification handler.
	socketNotificationReceived: function(notification, payload) {
			console.log ("socketnotificationreceived.")
		if (payload === "up"){
			console.log("test - up");
		}
		else if (payload === "left"){
			console.log("test - left");
		}
		else if (payload === "down") {
			console.log("test - down");
		}
} ```

Why is there no ccommunication between the helper and the script?	}

[Jopyth]

@kclemen Are you searching for the output in your browser console? The console.log("...") command from node_helper.js is shown on the console, however console.log("...") commands of your module will appear in your developer tools console in the browser (e.g. electron).

[kclemen]

@Jopyth said in skywriter - python to javascript:

developer tools console in the browser (e.g. electron).

Indeed, I want to see the output to verify the communication works.
Could you elaborate some more about the developer tools console?

ctrl + shift + i does the trick :)

@Jopyth you are a HERO. Last 2 days working on it, antd the trick was that simple!

[Jopyth]

@kclemen I was just pointing you in the right direction sometimes. ;) Best of luck with finishing the rest of the module.

[kclemen]

ok, for now the last question ;):

Uncaught reference error: gesture_up is not defined. I understand what this means, but I can’t figure out why it says that :s

	
	// Default module config.
	defaults: {
		gesture_up: 0,
		gesture_right: 0,
		
	},

	// Override socket notification handler.
	socketNotificationReceived: function(notification, payload) {
		if (notification === "gesture_observed"){
			const self = this;
			
			console.log ("socketnotificationreceived.");
		
			//self.sendNotification(notification, payload);
			
			if (payload === "up"){
				
				if (gesture_up == 0) {
					
					if (gesture_up == 0){
						gesture_up = gesture_up+1;
						
						console.log("gesture_up is nu 1");

[yawns]

Try this.config.gesture_up instead

[kclemen]

This helps indeed for the error, thanks. But how to use it like I want? I mean, how can you do calculations within following up socketnotifications? It looks like with every gesture the this.config;gesture_up starts with the value 0.