HLK-RM04 is a low cost UART-ETH-WIFI module. It can used to connect any microcontroller to internet/LAN. I just tried it for my latest Home automation project. Its a simple and cheap module for connecting the microcontroller using wifi. The HLK-RM04 is basically a Linux powered Router with serial port output.
Even i have used several serial-wifi modules before. But they are more complex and not stable, they often get disconnected from the network and draw more power. But this HLK-RM04 module is more stable/cheap/less power consumption. Its running in my home for more than 10days without any problem.
The first time user of HLK-RM04 may get confused with this module to get connected to your network. Even i struggled a little. So i am explaining here about setting up the module.
The HLK-RM04 is available alone and with base board. Check this images for the modules with and without base board
HLK-RM04 with base board
HLK-RM04 base board
The HLK-RM04 module is almost half price with base board. You need the base board only if you use the Ethernet cable. If you want to use wifi then there is no need for the base board. But if you are a beginner then better you buy with base board. But you can setup the module even without the base board. I am going to explain to setup the module without base board.
Basic Connection needed to setup the HLK-RM04
There are several methods to configure the module, i am using the wifi method and using a windows smartphone to do it. Connect the power supply (+5v to pin 1 and Gnd to pin2) and switch it now.
Switch ON the wifi on your smartphone
You can find the module as an Wifi AP Named HI-LINK_463F, Connect it to your phone. It will ask for the password, the default password is 12345678
It will say that it does not have internet connection as shown in the figure. But you can still connect to it
Now just open the browser and type 192.168.16.254 on the address bar. Now the page will ask the username and password which is admin for both.
Now you can see the settings page as shown below.
There are 3 modes of operation, which is given below.
Now select the second mode from the dropdown box at Netmode. Click the Scan button to scan all the wifi signals shown in the following figure.
- Ethernet mode -Which uses the ethernet connection using Base Board.
- WIFI Client mode -Which act as wifi client and connect to our Home wifi Router. I am using this mode.
- WIFI AP mode - Which is Router mode.
Now use the SSID name which is your home router. My ssid name is "myhome" and select Encrypt type and give the password for your home network. Also select the IP type as static and enter the Following IP address. You have to use the Gateway IP which is the IP address of your Home router. Also you can change the Baud rate of the serial port at this page.
After entering all values click the Save button. Now you will be disconnected and the router will reboot as wifi client and will connect to your home wifi network. Now you goto the wifi menu and connect to your home network.
If you have entered the correct details then if you just type the new IP address on your browser with the username and password as admin and you can see the module page as shown below.
This is the way you can setup the HLK-RM04 module with your Home network. If you entered anything wrong and need to reset the module to factory settings press the buttons S1 and S2 simultaneously for more than 5 seconds and repeat the step from the beginning.
if you need my help post it on the forum at http://www.8051projects.info/thread...-low-cost-embedded-uart-eth-wifi-module.5959/
Setting up HLK-RM04 low-cost embedded UART-ETH-WIFI module
Installing and seting up the HLK-RM04 UART-ETH-WIFI module