New M-code to send a network request

Nightreaver · 26 May 2019, 04:33

@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 · 26 May 2019, 09:48

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

fma · 26 May 2019, 13:20

Are not pullups already on the Duet?

Nightreaver · 26 May 2019, 16:43

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

pull up resistors

On https://forum.duet3d.com/topic/7269/duet-sometimes-really-slow-i2c-error-or/58 you said, between 1.3k and 2.2k, that works with Duet3d Wifi as well?

@fma Idk, I find it also a bit frustrating why there is no collection about I2C basics anywhere, I have to collect all the information I need to get started one by one...

dc42 · 26 May 2019, 16:54

If you have only the Duet and your I2C device on the I2C bus, and your I2C device doesn't itself have any pullup resistors, then you can go as low as 1K.

I2C isn't particular to the Duet, and there are plenty of pages about I2C on the web. What matters is that somewhere on the I2C bus you have pullup resistors, and they are not too strong that the I2C devices can't handle them, and not too weak that the capacitance on the I2C bus makes the rise time too long. Pullup resistors of 4K7 are commonly used with I2C, but lower value give better rise times and noise immunity.

The Duet does not have any pullup resistors on the I2C lines, because if you are not using I2C you could use them as general purpose I/O pins. The DueX2 and DueX5 do have pullup resistors, with value 1K on recent production and 4K7 on older boards.

Note, I2C was intended for connecting chips together on a single circuit board. It was not designed to work over any length of cable.

Danal · 27 May 2019, 01:31

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

@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?

It may very well be working, if it is reporting zero slaves found, if you have wired ESP<I2C>Duet. There are two possible reasons for this:

The Duet is a MASTER. It will never report to this script because the ESP is also a master when running this script. I pointed out the script only for general debugging... for example, if you have another I2C device with which to test, or take an arduino and load an example slave script, then use this polling script in the ESP, etc, etc. That script can be very helpful in general experimentation with I2C.
As mentioned, all I2C busses need pullups somewhere. It doesn't matter if the resistors are on the master or slave, M/S is a software concept. In fact, in certain circumstances, resistors in multiple places can be OK. This is because the I2C hardware protocol specification works by whomever is transmitting at that moment "pulling down" the lines. Therefore, a resistor is needed to pull them up when no one is transmitting.

Back to point (1) above: There seems to be no easy way to use an ESP8266 connected I2C with Duet. They both want to be master. I've seen some solutions floating around that MIGHT make an ESP work as a slave... but the postings are ALL sort of ambiguous around whether anyone got it to work. For sure, the standard "Arduino core on ESP" I2C library will not work as a slave.

Danal · 27 May 2019, 01:40

So, having said all of that, the origin of this thread was "M code to send a network request".

An ESP8266 could be very good at sending the network request... Tons of different libraries for every protocol under the sun, and the ESP can be a WiFi client, Access-Point, or both at the same time. Very capable little IOT network device.

I know it bothers people to have to add something to the already very capable Duet... but... come on, ESPs are easy to get for $4 to $6 US, even in low quantities, and can be had for even less if you are willing to order in quantity and wait for a direct Asian shipment. Anyway...

A Duet to ESP connection would work over TTL serial, very easily.

A Duet to ESP I2C might be made to work, if someone can find a library or whatever that makes the ESP work as an I2C slave. At this moment, I don't know of any that are proven to work.

fma · 27 May 2019, 05:13

There are some examples of I²C slave with the ESP8266 Arduino package, so I think it can work.

A Former User · 27 May 2019, 05:41

Seems ESP8266 as a slave is limited to 14khz with the current software implementation and it lacks proper hardware support. People report success between two ESP8266 but not with a non ESP master. Hoping to verify during the week

Nightreaver · 27 May 2019, 08:26

@dc42 Yes, I didnt mean infos about I²C in general, but related to the duet. But at one point everything will be discussed in the forums anyways.

@danal Yes ESP are cheap to get, i got 5 WemosD1 for 12$ ? they have the cheaper CH340 chipset, but that still works well after you installed the driver.

So you can get the high quality wemos here:
https://www.aliexpress.com/item/WeMos-D1-mini-PRO-analog-WiFi-D1-mini-PRO-integration-of-ESP8266-32Mb-flash-and-USB/32806566263.html

cheaper bulk wemos:
https://www.aliexpress.com/item/5pcs-D1-mini-Mini-NodeMcu-4M-bytes-Lua-WIFI-Internet-of-Things-development-board-based-ESP8266/32832024575.html

or the ESP32 wroom:
https://www.aliexpress.com/item/ESP-32S-ESP-WROOM-32-ESP32-ESP-32-Bluetooth-and-WIFI-Dual-Core-CPU-with-Low/32864722159.html

secondly:
afer adding the resisors (1k each) i was able to get at least an exception when i have scl/sda wrong way, so i think in general it "works"...

So even tho it doesnt work, i also thought about grabbing serial from the duet and build something around that.
But I dont really wanna sacrifice the usb for that. I have some USB-TTL laying around as well... just didnt check them for wiring on the duet/esp yet.

@bearer that is limited to ESP8266? and what about that ESP32? looks like a bigger package...

@fma I will check to figure something about the slave/master thing. General communication wasn't working yesterday... so i gave up at one point

A Former User · 27 May 2019, 08:56

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

@bearer that is limited to ESP8266? and what about that ESP32? looks like a bigger package...

AFAIK ESP32 has hardware I2C support.

There may be some WIP for 100khz I2C for ESP8266, but haven't seen the code as a PR for the ESP repo

cookie · 4 Jun 2019, 03:26

This is a very interesting topic. It would open a lot of possibilities for production printing. For now, I got to learn and find workarounds until Duet 3.

Thanks a lot !

JoergS5 · 17 Jun 2019, 05:31

ESP32 documentation of ESP-IDF says: "There are two I2C controllers on board of the ESP32, each of which can be set to master mode or slave mode.", so if ESP8266 is restricted, I would recommend ESP32.
The documentation is here: https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/i2c.html

fma · 17 Jun 2019, 05:42

This module could be a good candidate:

https://www.crowdsupply.com/unexpected-maker/tinypico

JoergS5 · 17 Jun 2019, 05:46

I will build an absolute optical encoder to get the actuator positions of the scara printer, so I use ESP-CAM to have the camera.

Nightreaver · 17 Jun 2019, 14:49

I think one issue is, that these device supporting that mode on hardware side, tho the implemenation is missing.
Last time i checked there was no slave implementation on Arduino side, tho micropython seem to have it.
I just didnt start setting up micropython yet....

JoergS5 · 17 Jun 2019, 16:29

@nightreaver I can give you my code when it's finished. But it will be C for ESP-IDF, not Arduino .ino.

tomwor2 · 25 Jan 2021, 21:40

Is there any new information on this topic? I am just getting my new printer fired up and was hoping to be able to send a message to node-red running on a Pi. Node-red manages most protocolls mentioned in this thread including MQTT, HTTP UDP and TCP, so for me it does not really matter which protocol that is used. It would be great to be able to for example shut down the machine when it's done using a smart plug och get a message when it runs out of filament etc.

DIY-O-Sphere · 26 Jan 2021, 10:25

@tomwor2
It works the opposite way...
If you are familiar with Note Red you can pull the status information from the Duet, run some code in Node Red and send any command back to the Duet via g-code....
https://forum.duet3d.com/topic/18520/node-red-mobile-sized-status-dashboard-for-duet

But for an easy shut down after print is finised, that it's not required.
You can use the PS_ON pin to switch the printer of.
Or a more current solution....
https://forum.duet3d.com/topic/19161/smart-remote-power-control

tomwor2 · 31 Jan 2021, 08:48

@DIY-O-Sphere said in New M-code to send a network request:

that it's not required.
You can use the PS_ON pin to switch the printer of.
Or a more current solution....

Thanks for the input. I was hoping to avoid having to turn on a node-red flow when I am printing and not have to buy more hardware but your input made me think around it a couple of more turns and I think I have come up with a workable solution.

I do not have a separate PSU for 5v as I plan to run the board only when the printer is turned on but I do have a smart home controller.

I'll simply activate the node-red flow every time the smart plug for the printer is turned on and turn it off after having ensured the printer is turned off. The smart plug was anyhow needed to shut the printer down when ready and I can also measure the power I consume for printing