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Build an IoT DMM, hardware engineer with smattering of software seeks software engineer ...

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LAN_403

Plasma

Fri Jul 20 2018, 01:02PM

Registered Member #61406 Joined: Thu Jan 05 2017, 11:31PM
Location:
Posts: 268

I'm not 100% sure, if you a form and click submit, it should appear in the urls, saying that both will work the data will be in the packet, but get will be near the top and you can manually enter it in the urls, anything that pass data to another page will work.
I think you will need a auto reload code and if in the index. Html you have hard code editing 123.4 when the dimm gets a value based on the settings the client submitted, you modify the 123.4 as the html page is in a string array, and then send that to the client with the auto reload code will after X time requests the page again.
I was never any good at html and JavaScript, you might want some else to answer that question.

the_anomaly

Fri Jul 20 2018, 04:54PM

Registered Member #19 Joined: Thu Feb 02 2006, 03:19PM
Location: Jacksonville, FL
Posts: 168

Get and Post are client requests to a server so I believe do_get() and do_post() are server side functions that fill those requests.

Generally, Get is used to retrieve information from a server and Post is used to send information to the server W3Schools Get/Post. My experience has been with writing trading bots for crypto exchanges and they manage to implement their API by using only Get requests. I am not sure what is the reason for this since one must send data to their server to execute a trade. You make the Get request in such a way the server can parse the request for the data it needs to take the action you want.

I think the best way to approach this project is to view the server as a slave device and the client(s) as both the webpage and the DMM. The DMM will send its data to the server periodically. Then the webpage using Javascript or some other client side language will request updates from the server to get the latest values. I should clarify it's the browser (Chrome/Firefox) that is the client not the webpage; ie. Javascript runs on chrome and makes Get requests to updates the webpage display. Making Get request with Javascript

As you indicated, it does not need to be a web page as a client, it could just be another device sitting on the network. This device will make the get requests to the server.

Without knowing more about Post requests, I think you should have the DMM make Post requests to the server to send over its data.

I could be out in left field on a bunch of this too...

Dr. Slack

Sat Aug 04 2018, 05:10AM

Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659

I think I've now got a handle on this, so probably no further help needed until I have some much more specific questions. Thanks to anyone who's tried to think down to my level and failed. I was approaching it at too low a level, trying to ride this horse in the direction it wasn't going.

After a month of having the odd poke around at google and youtube, I've realised there are lots of server tutorials around for the ESP82(66) hardware, acrobotic seems particularly thorough and at my level, that could get me going. As I can already drive Arduino, using the arduino core approach on the ESP82 looks like a good fit.

While a web server on the server is not necessarily efficient, a DMM is really slow, and all computers wait at the same speed. Getting python to make web requests to such a server would get me up and running. If I wanted I could then develop that into a human-usable web interface, or socket level server, but probably wouldn't need to do either.

Conundrum

Wed Sept 26 2018, 05:48AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4061

Hi, have you considered using yellow OLED panels for the display?
The ones here are basically the same but share a common controller and electrical interface.

Dr. Slack

Wed Sept 26 2018, 09:08AM

Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659

You know conundrum, I could have sworn that my question was about getting help with the software, rather than suggestions for what sort of display to use.

I've now bought a NodeMCU 8266, and established that the ArduinoCore tools do work to flash its LEDs. However, the funny thing is, I haven't been motivated to program it as a server and talk to it, preferring other jobs around the house and garden, and other programming projects. Perhaps that's part of wanting somebody to collaborate on software, to give me some motivation to do it.

Dr. Slack

Tue Oct 09 2018, 06:26AM

Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659

Actual progress! I think I ran out of other jobs to do, and perhaps the embarrassment of seeing this NodeMCU plugged into a breadboard, leering at me every morning from across the desk, propelled me into doing something.

I've elected to start playing with UDP rather than TCP, as it suits my dinosaur-like assembler brain better. I've now got a PC talking to itself, and to another on the network in python, and handling it when they're started up in the wrong order or stop responding for some reason. UDP is more than enough for 'take a reading' - 'here's the reading' exchanges. Tomorrow, the 8266!

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