Has anyone used this wifi module?

Hello everyone,

I would like to know if anyone has already used this wifi module : http://www.ebay.com/itm/HC-21-Embed-WIFI-to-Serial-Port-Wireless-Module-UART-for-Raspberry-pi-Arduino-/121292125857?pt=LH_DefaultDomain_0&hash=item1c3d92f6a1 I would like to know if I can use it with the wifi library?

Thank you in advance.

I thought to buy, but can not find library for arduio of modulo seems compatible, but can not find documentation on. Not sure if I buy this module. have you found any information about this?

I was interested in this module too, so a couple of days ago i asked the seller an english documentation, libraries etc.... He answered that this module has been developed completely in China and all the documentation that's available right now is in Mandarin, but they're working on a translation. So, we must keep waiting for news. He also told me that ,when available, all the documentation, libraries etc will be reported in a link on the ebay announcement page.

I found these modules at a couple of wholesalers I buy from and was going to buy a couple to play with. They look really nicely done.

However, I also got the 3373.zip file with the documentation, all in Mandarin. The thing that you need as well which isn’t there is that all of the supporting exe files come up with the utilities in Mandarin as well.

And the unit can be configured by connecting to which is also nice. The bad news is that the embedded device web page is in Mandarin as well. I know the embedded device and internationalization can be a real problem once you open the can of worms of needing the translations, but they could have or could provide a properly internationalized support utility. Also opening up the source would probably bring a better supported product. (my $0.02 worth on open source vs. proprietary). Also if it is open source you would have a chance of it being compiled and rebuilt in a couple of years when you need to change something.

Take a look on the Networking section, there are several postings on this general type of module. e./g. http://forum.arduino.cc/index.php?topic=232908.msg

I have done extensive work on the model with TLN13UA06 written on it.

The one you linked to looks similar to mine, but not quite the same

I have built a simple web server using the TLN13UA06

Take a look on AliExpress http://www.aliexpress.com/item-img/2-4G-Wireless-Module-Embedded-Uart-Wifi-Module-UART-WiFi-Network-Server-Client-IEEE802-11b-with/988481350.html

Note. I'm not saying these are the easiest devices to use, and no one has written a proper library (I've started but not completed a library)

But they are super cheap for what they can do.

Thanks for the pointer, Roger. That unit certainly looks the same. you mentioned in the threads you pointed at that there was a port 50000, so I'm guessing you know if the port is in Mandarin, or English? Just curious.

I found the FZ0417 module on ebay for 17.50, 4 dollars more than the aliexpress price, as well.

I was not a fan of configuring by using AT but you're certainly right that should not be a problem for one due to language.

Did you manage to find a copy of the documentation for this board? I think it was an aliexpress seller for the board I posted that had a zip with the utilities, etc., in it.


has the data for this board. All Mandarin, near as I could tell.

I didn't see it in the thread (nor did i have a chance yet to look completely thru your thread) for the other board. thanks Jim

These boards have a default port that is defined in their firmware and also stored in Flash RAM.

Stranglely the module I got was initially on port 5000 but when I gave it the command to return to factory settings it moved to a different port.

So someone in the supply chain had changed their default params.

If you look the HC-21 manual doc in link, on page 5 it says its a TLN13UA06 ie the same module that I have

But looking at the board photo its doesnt look quite the same.

So either the are not supplying an item that matches the photo, or the docs are not correct.

BTW. The thread is huge, as Federic preferred if I posted replies to his thread, rather than via PM ;-) so everyone gets the benefit

PS. I've also had one other person PM me about these modules (Larry) and he has ordered 2 of them. I presume he ordered TLN13UA06 but who know what he'll get from AliExpress ;0)

One thing to note, both Frederic and I had to put different firmware on our modules. As Frederic found one of his modules worked fine but the others had issues when creating server sockets. Neither of mine worked correctly (apart from in the basic RS232 over wifi mode), so I put the revised firmware on both of my modules and it fixed the problem Note the revised firmware is older than the supplied firmware ie 2013 version instead of the 2014 version, and the revised firmware is a file I found on a product site where they use the module to turn on and off a light !!

But it works !! and Wifi for less than $15 is a bargain ;-)

BTW. I uploaded all the docs I could find on my board to GitHub. https://github.com/rogerclarkmelbourne/Arduino/tree/master/libraries/UARTWifi/useful_docs

Perhaps not the ideal location, but at least they are available for anyone to look at

Just bought the HC-21 for my arduino nano.

Does anyone can point me where I can connect the pins to my Nano ? I think I make some mistake connecting this wifi module to my nano pins.

I managed to connect this device to my network but how do I use the tx and rx pins to send commands to arduino uno?

Documents in ENGLISH can be found here.... http://storage.googleapis.com/ebimg/HC-21/HC-21%20Documentation%20-%20English.zip

See this thread. It appears the module is basically the same one


Note this is a very long thread but Frederick and I posted a lot of useful information

Oh UAO3, another alias... Sorry for double post, let me digest that threats and links

Thank you

Connecting the module can be done by simple navigating to it's ip address with a wifi adapter and matching your networks settings. The next set of questions involve the direct communication from the module to arduino...

The module will communicate with a webpage (somewhat) but how should I go about the sketch? All the posts I found online about "web controlled relay, led, switch, etc..." use the wifi SHIELD not a module. Changing the values from Ethernet to WIFI demonstrates in testing that the code works, but the actuality of the code does not.

The one that used processing as a "buffer?" works well. But, the practicality of using serial wifi on a computer with processing is only useful when you don't have wifi/ethernet already existant on that computer.

EDIT: So I guess in short, how do I say... turn on/off an led from a webpage with THIS module?

Also, once you setup the module, it is present on the network without any further initialization. IE:

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; //physical mac address
IPAddress ip(192,168,1,102); // ip in lan
IPAddress gateway(192,168,1,1); // internet access via router
IPAddress subnet(255,255,255,0); //subnet mask

is not required anymore??

Where did you find that code?

It doesn't look like code compatible with these modules

Did you take a look at the web server code I posted on GitHub ?


I hope you are doing well,

I recently started working on TLN13UA06. I have downloaded the datasheet mentioned above which is in Chinese Language. I translated it using Google, and found there are lots of AT commands set available which are not mentioned in Electrohouse module user manual. If any one interested I can upload it and share with you. Thanks

Bump to this, I had 4 TLN13UA06 Modules and SUDDENLY 3 of them died without any reason. All were supported with 3,3v (checked twice with different multimeters). Anamnesis: Turns on, only red led working (no green, not even blinking). Tried USBTTL to connect via COM, it couldnt locate device. Tried to send AT commands - no reply at all. My last module still working fine with same power source. Any suggestion? Did all test with power source, even with oscilloscope - its damn 100% legit. Tried to adjust voltage with dead one up to 5v - no effect. Weird!

Can someone give me a simple program to communicate 2 HC 12 using Arduino Nano and Mega...Please