Error: Invalid response from Ambient module

[snollygolly]

I'm following the example on http://tessel.github.io/t2-start/modules/ambient.html but I can't get my module to work. This is what I get:

INFO Looking for your Tessel...
INFO Connected to Charmander.
INFO Building project.
INFO Writing project to RAM on Charmander (42.496 kB)...
INFO Deployed.
INFO Running index.js...
/tmp/remote-script/index.js:1
(function (exports, require, module, __filename, __dirname) { var t=require("tessel"),n=require("ambient-attx4"),e=n.use(t.port.A);e.on("ready",function(){setInterval(function(){e.getLightLevel(function(t,n){if(t)throw t;e.getSoundLevel(function(e,t){if(e)throw e;console.log("Light level:",n.toFixed(8)," ","Sound Level:",t.toFixed(8))})})},500)}),e.on("error",function(e){console.log(e)});
                                                                                                                                                                                                                                                                ^

Error: Invalid response from Ambient module
    at Error (native)
    at null.<anonymous> (/tmp/remote-script/node_modules/ambient-attx4/index.js:1:2516)
    at null.<anonymous> (/usr/lib/node/tessel-export.js:296:31)
    at emitNone (events.js:67:13)
    at Socket.emit (events.js:166:7)
    at emitReadable_ (_stream_readable.js:411:10)
    at emitReadable (_stream_readable.js:405:7)
    at readableAddChunk (_stream_readable.js:157:11)
    at Socket.Readable.push (_stream_readable.js:110:10)
    at Pipe.onread (net.js:523:20)

I also tried running the ambient triggers example, and it doesn't crash like this one, but it doesn't seem to register sound or light.

[corymickelson]

I get the same response running the demo code

[johnnyman727]

Thanks, I'll check that out this week.

[draco2003]

+1 for seeing this error:

https://forums.tessel.io/t/tessel-2-error-invalid-response-from-ambient-module/2316

[johnnyman727]

Thanks everyone. It's likely that because T2 is faster than T1, we're running into issues that we haven't seen before. I think it can likely be fixed by making sure all messages sent between the Tessel and the module are serialized (ie don't send the next packet until you got a response from the previous) but I won't get a chance to work on this until later this week (currently working on install issues). @corymickelson or @draco2003 if you want to work on a fix, I can help advise in the meantime.

[draco2003]

I won't get a chance to work on it this week, but i did notice that it randomly updates the firmware as well, which might be a related issue when it's asking for the firmware version info.

[johnnyman727]

Thanks for the extra info @draco2003.

[corymickelson]

I can give it a go this weekend.

[seiyria]

Just wanted to note that this happens to me regularly. I take a reading of data every 5 minutes for a chart for my place of residence, and the ambient module seems to just die randomly. Same error as stated in the topic.

[johnnyman727]

@seiyria thanks for the feedback. I worked on this a bit early this weekend and this PR should fix a good number of these issues. I'm going to continue investigating though.

[seiyria]

@johnnyman727 thanks, I've subscribed to that PR. I'll watch and update you if my situation changes.

[johnnyman727]

Some investigation into this problem. I have a screen grab of when the error occurs based on this example code:

var tessel = require('tessel');
var ambientlib = require('../'); // Replace '../' with 'ambient-attx4' in your own code

var ambient = ambientlib.use(tessel.port['A']);

ambient.on('ready', function () {
 // Get points of light and sound data.
  setInterval( function () {
    ambient.getLightLevel( function(err, lightdata) {
      if (err) throw err;
      ambient.getSoundLevel( function(err, sounddata) {
        if (err) throw err;
        console.log("Light level:", lightdata.toFixed(8), " ", "Sound Level:", sounddata.toFixed(8));
      });
    });
  }, 500); // The readings will happen every .5 seconds
});

The problem occurs with the second transaction (requesting the sound data).

The first transaction can be analyzed as:

Tessel

0x2 = Send me light data
0x1 = Just send me one reading
0x0 = Dummy byte
0x0 = Dummy byte
0x0 = Dummy byte
0x16 = End of transaction

Ambient

0x55 = Confirming we are starting a transaction
0x2 = Confirming you want light data
0x1 = Confirming you want 1 reading (16 bits)
0x0 = High data byte
0x6F = Low data byte
0x16 = End of transaction

Then we can see the problem with the second transaction when we request sound data:

Tessel

0x3 = Send me sound data
0x1 = Just send me one reading
0x0 = Dummy byte
0x0 = Dummy byte
0x0 = Dummy byte
0x16 = End of transaction

Ambient

0x0 = Confirmation byte (SHOULD BE 0x55)
0x05 = Confirming command type (SHOULD BE 0x03)
0x51 = Confirming you want 1 reading (SHOULD BE 0x1)
0x0 = High data byte
0x0 = Low data byte
0x0 = End of transaction (SHOULD BE 0x16)

I'm not yet sure why the ATTINY is not able to respond correctly to such a simple command. My guess is that the SPI protocol or timing is not what it's expecting.

[johnnyman727]

This should be fixed with a combination of c11274f and tessel/t2-firmware#209.

Should be closed once tessel/t2-firmware#209 is merged and a new firmware build is released.