Asking for advice on cheap microcontroller board with Wireless and TCP/IP - Page 1
Forum section: electronics / beginners

author: BobbyK
author_rank: Regular Contributor
timestamp: February 19, 2017, 12:34:22 am
content: I am looking for a cheap board that can create various standard IR signals, taking commands that it reads from a web server. It should be able to connect securely to a normal wireless router, connect to an internet address, request URLs and process the returned JSON. These values then trigger a routine to create the IR signals. I have worked with an Arduino + wireless shields before, but I am hoping to keep the cost minimal this time. I have also looked at the ESP8266-based NodeMCU, but it so far it seems it can only connect to a very specific server. Does anyone know of alternative solutions, with a low cost and gentle learning curve for my purposes. I would appreciate any help here. Thanks in advance.

author: drunkenbeagle
author_rank: Newbie
timestamp: February 22, 2017, 04:11:37 am
content: The TCP/IP stack and wifi modem rule out most microcontrollers, they don't have either the memory or speed to deal with IP networking and wifi adapters. Handling that requires a lot of software, that just isn't going to fit in the 32k that microcontrollers typically have to work with.That said, anything complex enough to handle the wifi and IP stuff will work just fine for driving an IR LED.The ESP8266 would work fine for what you want. It doesn't need to be programmed in LUA with nodeMCU, you can program the things with the Arduino software as well. You'll need a USB-TTL cable to program it, which will need Rx/Tx/DTR broken out. The downside of the ESP8266 is that it needs a lot of power, at least a few hundred mA. You'll also be writing a lot of code, as there probably aren't Arduino libraries for the JSON parsing you'll need.A Raspberry Pi (or one of the clones) is a good choice too. It won't use that much more power than the ESP8266, and has a pin header for the GPIO you need for the IR, and has an entire Linux distro running on it. A big plus, as the software you need for parsing JSON is already there, and the networking is standard Linux stuff (well documented and works well), and you can use the Linux LIRC package to handle all of the IR stuff. I would do this if you aren't making thousands of these things. Even then, I would do this first as a prototype.

author: chota.sanjiv
author_rank: Contributor
timestamp: February 22, 2017, 08:47:08 am
content: tryhttp://www.emcraft.com/,they have solution based on stm32f4 and Linux, production will be cheap and all opensource software.

author: cowana
author_rank: Frequent Contributor
timestamp: February 22, 2017, 09:05:17 am
content: Quote from: drunkenbeagle on February 22, 2017, 04:11:37 amNot true - there are quite a few JSON parsing libraries for the ESP8266/arduino. The only limitation I've found is the RAM limits the maximum string length to around 1000 characters (in my experience) - but that shouldn't be an issue for this application.

author: BobbyK
author_rank: Regular Contributor
timestamp: March 19, 2017, 09:48:26 pm
content: Thanks everyone. I went with the ESP8266 and got the project to work. My code barely fit on there...but it's adequate, and it does seem to be the cheapest option.

author: ebclr
author_rank: Super Contributor
timestamp: March 20, 2017, 01:11:51 am
content: That's the board familyESP32many options availablehttps://www.google.com.br/search?q=esp32+board&rlz=1C1CHZL_pt-BRBR723BR723&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiMrYmh8-PSAhUGlpAKHW4uBfkQ_AUICCgB&biw=2327&bih=1247

author: FrankBuss
author_rank: Unknown
timestamp: March 20, 2017, 01:41:14 am
content: Quote from: BobbyK on February 19, 2017, 12:34:22 amNo, it can connect to any server, I've tested it:https://www.eevblog.com/forum/projects/how-to-setup-a-rapid-development-environment-for-nodemcu-and-lua-scripts/

author: ebclr
author_rank: Super Contributor
timestamp: March 20, 2017, 07:23:07 am
content: ESP32 is not ESP 8266 is much powerfulYou can connect to ANY server with propriety software there is the sock connection, after that is only a question to find or implement any protocol, The cpu is powerful double core and a lot of memoryThe unique obstacle may be you because need your software to operateA video what things that are possiblehttps://youtu.be/6SR7anr_Xi4