New M-code to send a network request

Danal

@lostapathy said in New M-code to send a network request:

Mine's on my NAS, but you can run that anywhere, or use a public one in the cloud.

No thanks. With all due respect, the concept of having a NAS, or server, or cloud be REQUIRED for my printer to trigger the camera that is bolted to it (or similar)...

I totally get having such a service/broker for tens, hundreds, thousands, ... of IoT devices. For what should be totally local interaction between two or three endpoints, MQTT feels (to me) even "heavier" than some of the things we've already rejected.

Danal

HTTP with option for ultra-quick timeout seems to be a pretty good hammer.

Still like to see an UDP option, but I seem to be in the miniority for that, and the existing internals of Duet/RepRap/WiFi-module also don't seem amenable.

So... HTTP with timeout options. Sounds pretty good.

Mnnn [resolvable name|IP] [timeout in ms] "payload"

Should there be an option to express a payload buffer entirely in Hexadecimal?

Danal

@oddkode said in New M-code to send a network request:

Another idea I've been toying with. I've downloaded DWC to try and see if it's possible to raise a JS event upon layer change.

Yes, but... DWC just polls. Nothing is ever "pushed" to DWC from the printer. If you are already polling, no need to 'hook' DWC.

I was hoping I could tap into the field that stores the IP / web camera URL

You can certainly get that from DWC internally (JS read the HTML field, among other things), but there is a potentially easier way: DWC stores its persistent settings in a file on the printer itself, and pulls them via an AJAX call. You can either:

HTTP download the file

http://192.168.1.100/rr_download?name=DWCconfig.txt

Or make an AJAX call (still really an HTTP GET) for a JSON object (containing the same info)

http://192.168.1.100/dwc.json

Note: REALLY old DWC kept config in a cookie; then DWC kept it in local browser storage... but for some time now, the above has worked. So you should be able to ignore those old ways.

Nightreaver

I think having MQTT for this scenario makes sense to me.

I already like the Idea of having MQTT as part of the DuetFirmware as described here: https://github.com/dc42/RepRapFirmware/issues/284

Having a more detailed status will allow you to use MQTT to do lots of things with the report.
Even taking a picture would be possible that way if the status is properly prepared.

So lets say the MQTT connection is setup like wifi with some M-code, and you have another "M-code" (like M118 Px) to send a message to a MQTT topic, which is checked form another service/agent that will take care of anything else.

Also like mentioned in my ticket, you can use it to tigger power supplies like Tasmota-Compatible via Homeassistant/OpenHAB.

Setting up the Broker itself is part of another system, you usually dont use MQTT if there itsn't anything else in place. For these scenarios you might already have a broker running. Even if not, that broker can simply run on a RaspberryPI that you might use for the Webcam as well.

I really support that MQTT idea. MQTT with a proper topic-layout can be used to do many many more things...

Nightreaver created this issue in dc42/RepRapFirmware

closed MQTT Status Update / MQTT power control #284

fma

Why not just use a little RPi Zero W, and connect it to the Duet via I²C? RRF can send I²C commands, so once the RPi is set up, you can do whatever you want (up to cmplex tasks). An ESP8266/32 could also do the job.

Jacotheron

Regarding the RPi Zero W on I2C, we should just remember that at present a RaspberryPi can't be an I2C slave (it can communicate with I2C devices, but other devices can't establish a connection to them). I have spent a few days trying to set it up (in my case it was trying to safely shutdown the Pi, before the printer shuts itself down).

fma

I didn't know that. Too bad So one should use Arduino/ESP...

Nightreaver

yes you might use it, but then I'm having another ESP32/8622 device beside the esp of the duet, to get a feature via I2C that could be "easily" integrated via MQTT on the current duet?

I know there is many workaround to solve my issue, but MQTT is a neat solution.

Also think of this
https://forum.duet3d.com/topic/9668/telnet-printing-using-a-filament-monitor

There is already solution that work with MQTT and telegram.

So i.e. the Duet is updating a "Status" mqtt topic, when this is changing to "out of filament" send a telegram message. no need of utilizing and coding arduino or micropython. it can be done with much simpler and higher level language.

And as other already said, why do i have need to have another device for much simpler things when i already have a 179$ duet in place.

Feels like fixing my porsche with cheap volvo parts...

fma

@nightreaver said in New M-code to send a network request:

And as other already said, why do i have need to have another device for much simpler things when i already have a 179$ duet in place.

Well, I like the idea to have multiple simple systems doing specific tasks, and doing them well, rather than heavy things doing badly a lot of stuffs... Maybe RRF needs a good hooks system, with a simple and powerfull com design, to allow us to expand its capabilities without the need to modify the firmware, introducing complexity and potential unstability...

Feels like fixing my porsche with cheap volvo parts...

What a waste of Volvo parts

dc42

I have it on the list for RRF3 for the Duet to be able to send network messages. Whether we support sending via HTTP or MQTT or something else has not been decided yet.

dc42

@fma said in New M-code to send a network request:

... Maybe RRF needs a good hooks system, with a simple and powerfull com design, to allow us to expand its capabilities without the need to modify the firmware, introducing complexity and potential unstability...

That's hard to do on Duet 2, but it will be provided on Duet 3 right from the start.

Nightreaver

@dc42 said in New M-code to send a network request:

I have it on the list for RRF3 for the Duet to be able to send network messages. Whether we support sending via HTTP or MQTT or something else has not been decided yet.

IMHO is MQTT THE IoT protocol.

Other opinions ( "mqtt vs http" ) :

https://medium.com/mqtt-buddy/mqtt-vs-http-which-one-is-the-best-for-iot-c868169b3105
https://www.linkedin.com/pulse/internet-things-http-vs-websockets-mqtt-ronak-singh-cspo
https://cloud.google.com/blog/products/iot-devices/http-vs-mqtt-a-tale-of-two-iot-protocols

I'd probably not go, an reinvent the wheel with "something else". But im biased

Nightreaver

@fma said in New M-code to send a network request:

Why not just use a little RPi Zero W, and connect it to the Duet via I²C? RRF can send I²C commands, so once the RPi is set up, you can do whatever you want (up to cmplex tasks). An ESP8266/32 could also do the job.

So how would I utilize I²C on duet? I mean.. in need something while no solution is there.

I'd like to get:

power on/off before/after print
print status / filament status

I think if you can point me to any of these, I can figure out everything else

fma

M260 can send data over I²C bus:

https://duet3d.dozuki.com/Wiki/Gcode#Section_M260_i2c_Send_and_or_request_Data

On the I²C slave, just mimic some registers you will write from Duet to take the actions you need.

I recently developped a project using an ATtiny841 as I²C slave (this chip as a hardware I²C slave implementation), working this way. See:

https://framagit.org/fma38/Servo_Node

This is for an hexapod (I will use 6 of them, to control the 4 servos of each leg). But I will certainly use this chip for other projects, like here.

Code in Arduino/ dir is a master example; the real master will be a RPi, running my framework Py4bot: https://framagit.org/fma38/Py4bot

Nightreaver

@fma can i also get a hook in power on/off before and after a print?

Also is there a way to get serial through not usb?

fma

You can send I²c commands from your start and stops scripts.

You can drive the Duet from the LCD connector instead of USB port (This is a serial TTL, you need a TTL-RS232 converter to hook it to a PC serial port).

Nightreaver

@fma I want to use a WemosD1 because I got a couple for cheap. Im currently struggleing getting the I2C connection working (total noob on arduion and I²C)

The wemos is a 3v3 device, so I can use without a level shifter. Ive use the pins of the expansion board.
0_1558808799959_945279ed-cd99-48cd-9302-b77d6e3c201a-image.png

I assume sda is TWD, and scl is TWCK ?

What else do I need?

I'm giving my device a 0x08 address and send the following from the duet: M260 A"x08" B99 or M260 A8 B99
But I cant see anything happening tho.

Did I miss something or is it just a coding/cabling issue? The wires are ~10cm

Danal

@nightreaver said in New M-code to send a network request:

I assume sda is TWD, and scl is TWCK ?

ESP8266s do I2C in firmware, not hardware. Whatever pins you assign in the wire.begin() will work, with very few exceptions. I do encourage you to use "Dn" format, vs. just a number, the Dn are defined to map properly to the silkscreen on the board. Also, as far as I know, and ESP8266 can be an I2C master, but not a slave.

And... this may help your efforts. This sketch scans the I2C bus and tells you the addresses of all slaves that respond. I've tried it, and it does work. I don't remember where I got it, and its own header comments don't say.

/*
 * Wire - I2C Scanner
 *
 * The WeMos D1 Mini I2C bus uses pins:
 * D1 = SCL
 * D2 = SDA
 */

#include <Wire.h>

const int sclPin = D1;
const int sdaPin = D2;

void setup()
{
  Wire.begin(sdaPin, sclPin);

  Serial.begin(115200);
  Serial.println("I2C Scanner");
}

void loop()
{
  byte error, address;
  int nDevices;

  Serial.println("Scanning...");

  nDevices = 0;
  for (address = 1; address < 127; address++)
  {
    // The i2c scanner uses the return value of
    // the Write.endTransmisstion to see if
    // a device did acknowledge to the address.
    Wire.beginTransmission(address);
    error = Wire.endTransmission();

    if (error == 0)
    {
      Serial.print("I2C device found at address 0x");
      if (address < 16) {
        Serial.print("0");
      }
      Serial.print(address, HEX);
      Serial.println(" !");

      nDevices++;
    }
    else if (error == 4)
    {
      Serial.print("Unknown error at address 0x");
      if (address < 16) {
        Serial.print("0");
      }
      Serial.println(address, HEX);
    }
  }
  if (nDevices == 0) {
    Serial.println("No I2C devices found\n");
  }
  else {
    Serial.println("Done.\n");
  }

  delay(2000);
}

Nightreaver

@danal Hey, i found that scetch on github yesterday. I assume it's the esp sample library. Nonetheless I tried it and didn't work for me. I also changed to pins in the firmware, so i assume the pins on the duet i use are wrong, or i missed a cable.
Are the marked pins good for i2c communication on the duet? Do i need any more wires or connections?

dc42

You need to add pull up resistors between each of the I2C lines and +3.3V.