Espruino JavaScript
Connecting EspruinoWiFi to computer over WiFi #936
Replies: 18 comments
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Posted at 2017-06-02 by @allObjects ...get Web sockets going... or on a higher level mqqt... there are plenty examples out there... |
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Posted at 2017-06-02 by trusktr Hmmm, maybe I can request a predefined IP on the computer DHCP, then just have espruino talk to that IP hard coded. Gonna try that out... |
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Posted at 2017-06-02 by trusktr @allObjects I see the |
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Posted at 2017-06-02 by trusktr Seems to me like the client (espruino using |
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Posted at 2017-06-02 by trusktr Alright, I think I found a way, Chrome OS has a "network" tab for my wifi connection, and I can turn of automatic configuration and specify an IP address. I think now I can just use the |
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Posted at 2017-06-02 by trusktr I know the IP of my computer, but when I try require("http").get('http://192.168.0.5:3000', function(res) {
res.on('data', function(d) {
console.log("--->"+d);
});
}).on('error', function(e) {
console.log(' --- ERROR: ', e)
});it shows the error But I can access Any thoughts on why Espruino might not be able to access it? EDIT: hmm, I can access the Espruino if I know it's IP: Is there a way to make Espruino's IP static? |
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Posted at 2017-06-02 by @gfwilliams I just posted a workaround for setting a static IP address here: Assuming that works for you it could easily be rolled into the EspruinoWiFi library. I'm not sure why you're not getting a response from |
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Posted at 2017-06-02 by @allObjects @gordon, great idea... and the IP can be put into a module to externalize the same way as the network credentials - SSID and password - as mentioned in this (and another) post. You place the module code as The creds object can be complemented with other information you need, but at some point you will just create another object of less data privacy and call it cfg and store and use it the same way as the creds object. Giving the module a suffix (and id to the object) - such as XYZ - you can have multiples and load the code to the different devices with respective credentials and configuration. 2cts about code modularity / reuse / 'hiding'. |
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Posted at 2017-06-03 by trusktr
That didn't seem to work at all on the Espruino end, but I didn't check if the server received anything. However, now I'm connecting from computer to Espruino. What I'm currently doing is the browser sends a websocket request to the local Meteor server (simply calling an RPC method defined on the server, not needing to know Meteor's DDP websocket API), then the server does a It takes 120 to 200 milliseconds for the server to receive a response back from the Espruino. This includes the time it takes for Espruino to request data from the MPU6050 module. So it's not really ideal for realtime visuals. I haven't timed how long the MPU6050 request takes yet. At first I tried the browser's new So instead of making direct HTTP requests from the browser I am going through the local Meteor server which obviously will take longer. Do you know if the Espruino WiFi is capable of replying with data over WiFi at a speed closer to something usable with a graphical application? If not, maybe can you recommend a chip that is easy to install Espruino firmware on, so that it can be faster (and just as easy to connect to in Web IDE)? |
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Posted at 2017-06-05 by @gfwilliams I think you'd struggle with sensible realtime speeds using individual HTTP requests... On pretty much any device running Espruino. What about just using websockets, or opening a direct socket connection to Espruino? Those would be really quick (especially sockets). |
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Posted at 2017-06-09 by trusktr Thanks for the tips @gordon. I gave websockets a try on Espruino Wifi, like the following, and it seems to work at a reasonable rate that could be used for animation, however every few seconds or so the incoming values on the UI seems to pause for a very noticeable while. Could it be GC on Espruino? Maybe there's some way to smooth it out? By values, I meant that Chrome console shows a counter for every time the same thing is logged. So this counter increments, it isn't really a value sent from Espruino, but the counter pauses every short while, which could cause "jank". I wonder if it is possible to fix that. function getMPU() {
I2C1.setup({scl:B6,sda:B7, bitrate: 100000});
var MPU6050 = require("MPU6050");
console.log(MPU6050);
var mpu = MPU6050.connect(I2C1);
return mpu
}
function connectToWifi(wifiName, options) {
var resolve, reject
var promise = new Promise(function(res, rej) {resolve = res; reject = rej})
var wifi = require("EspruinoWiFi");
wifi.connect(wifiName, options, function(err) {
if (err) reject(err);
resolve();
});
return promise
}
connectToWifi("starlancer", { password : "Next stop: Mars." })
.then(function() {
const mpu = getMPU();
const wifi = require("EspruinoWiFi");
wifi.getIP(function(err, info) {
if (err) throw err
console.log('IP:', info.ip)
});
var page = '<html><body><script>var ws;setTimeout(function(){';
page += 'ws = new WebSocket("ws://" + location.host + "/my_websocket", "protocolOne");';
page += 'console.log("host", location.host);'; // <--------------------- this is logged slowly.
page += 'ws.onmessage = function (event) { console.log("MSG:"+event.data); };';
page += 'setTimeout(function() { ws.send("Hello to Espruino!"); }, 1000);';
page += '},1000);</script></body></html>';
function onPageRequest(req, res) {
res.writeHead(200, {'Content-Type': 'text/html'});
res.end(page);
}
var server = require('ws').createServer(onPageRequest);
server.listen(8000);
server.on("websocket", function(ws) {
ws.on('message',function(msg) { print("[WS] "+JSON.stringify(msg)); });
setInterval(function() {ws.send("Hello from Espruino!");}, 42);
});
});
function onInit() {
console.log('Espruino started!');
}Thanks for all the help! I am loving to learn, but I have a long ways to go. |
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Posted at 2017-06-09 by trusktr I wonder what happens if the Espruino sends too many values faster than the network can handle? I wonder if it can crash if it is sending too fast, and how to prevent that. Could that be a problem? |
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Posted at 2017-06-09 by trusktr Cool, even a higher rate for the interval like |
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Posted at 2017-06-09 by trusktr Alright, so I'm trying it with actual values from the accelerometer, but that really slows it down. For example: function getMPU() {
I2C1.setup({scl:B6,sda:B7, bitrate: 100000});
var MPU6050 = require("MPU6050");
console.log(MPU6050);
var mpu = MPU6050.connect(I2C1);
return mpu
}
function connectToWifi(wifiName, options) {
var resolve, reject
var promise = new Promise(function(res, rej) {resolve = res; reject = rej})
var wifi = require("EspruinoWiFi");
wifi.connect(wifiName, options, function(err) {
if (err) reject(err);
resolve();
});
return promise
}
function getIP() {
const wifi = require("EspruinoWiFi");
wifi.getIP(function(err, info) {
if (err) {
console.log('Wifi connection failed, trying again in a sec...')
setTimeout(getIP, 1000)
}
console.log('IP:', info.ip)
});
}
connectToWifi("starlancer", { password : "Next stop: Mars." })
.then(function() {
getIP();
var server = require('ws').createServer(function() {});
server.listen(80);
server.on("websocket", function(ws) {
ws.on('message', function(msg) {
print("[WS] "+JSON.stringify(msg));
});
const mpu = getMPU();
setInterval(function() {
let result = {
acceleration: mpu.getAcceleration(), // returns an [x,y,z] array with raw accl. data
gravity: mpu.getGravity(), // returns acceleration array in G's
rotation: mpu.getRotation(), // returns an [x,y,z] array with raw gyro data
degreesPerSecond: mpu.getDegreesPerSecond(), // returns gyro array in degrees/s
}
result = JSON.stringify(result)
ws.send(result);
}, 16.666);
});
});
function onInit() {
console.log('Espruino started!');
}And the browser just does something like let mpuData = {...defaults};
let ws = new WebSocket("ws://192.168.43.247/my_websocket", "protocolOne");
ws.addEventListener('message', ({data}) => {
mpuData = parseEspruinoJson(data)
});
// ... use mpuData in requestAnimationFrame loop ...The rendering in my animation loop is slow now that I'm sending actual MPU data. Also after a short while I start to see some out-of-memory output until it crashes: _____ _
| __|___ ___ ___ _ _|_|___ ___
| __|_ -| . | _| | | | | . |
|_____|___| _|_| |___|_|_|_|___|
|_| http://espruino.com
1v91 Copyright 2016 G.Williams
>
=undefined
IP: 192.168.43.247
{
"connect": function (a,c) {return new b(a,c)}
}
[WS] "Hello to Espruino!"
ERROR: Out of Memory!
Execution Interrupted
Execution Interrupted
Execution Interrupted
Execution Interrupted
Execution Interrupted
Execution Interrupted
Execution Interrupted
Uncaught InternalError: Timeout on I2C Read Receive
at line 1 col 66
...is.i2c.readFrom(this.addr,6);a=c[0]<<8|c[1];var b=c[2]<<8|c[...
^
in function "readSXYZ" called from line 1 col 17
this.readSXYZ(59)
^
in function "getAcceleration" called from line 2 col 51
...ation: mpu.getAcceleration(), // returns an [x,y,z] array wi...
^
in function called from systemIt seems like trying to read MPU and send over socket every What might be the best way to do this to get values as fast as possible and not crash it? Maybe I need to be able to somehow detect how many network request and/or MPU requests are queued, and not request faster than is possible, somehow? |
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Posted at 2017-06-09 by @gfwilliams Yes, I imagine every 16ms is too quick, and likely the data is just getting buffered until you run out of memory. It's a difficult one - it is possible to actually look at the internals of the socket connection and see how much data there is in the buffer, but personally I'd say just back off a bit until you get something that works reliably. Obviously if you've got the buffer even at all full then that's data that is being delayed from being sent - so having slower data is better than having fast data that's out of date. Also - try sending the data as binary, or at the very least change the existing JSON so you sent a As for the pause, I don't know what to suggest - maybe blink an LED each time Espruino takes a reading so you can see if it's the Espruino or something else that's causing the delay. Espruino's GC is called very rarely, and is designed to be super-fast (it should be well under 2ms) so you shouldn't notice it at all. |
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Posted at 2017-06-09 by @gfwilliams Just an update on what you can expect:
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Posted at 2017-06-09 by dave_irvine Might be worth noting that you can get a fair bit more out of the WiFi in terms of baud rate if you configure it. |
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Posted at 2017-06-09 by @gfwilliams Yes - but to do it reliably you'd need a build for the Espruino WiFi from Git, and to tweak the EspruinoWiFi libs to enable flow control. That's opening a whole new can of worms :) |
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Posted at 2017-06-02 by trusktr
I'd like to connect Espruino WiFi to my computer over WiFi so that I can send data from (f.e. accelerometer data) from Espruino to the computer without a wired connection.
I could easily set up website and communicate through it, but that would be too slow.
When both devices are connected to a router, I am thinking to have the computer scan the network for IPs and send a request to each one, then Espruino will reply when the computer hits its IP and then the computer can know which one is Espruino.
Is there a better way? Maybe I can pre-configure the IPs and just hard code them? Any tips on how to do it?
Maybe it is possible to do it directly from computer to Espruino with Espruino is a WiFi AP? Would that work and be better?
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