432-434Mhz range spectrum analyzer based on HC-12

a simple RF spectrum viewer in a very small form factor

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I just wanted to do a simple thing with the HC-12 module to test an idea... and I did it and this thing is working better than I expected!

This simple thing is RF spectrum analyzer whithin range 432.9-434.9MHz. 
It  consists a HC-12 and an OLED display(0.91") and a TC4056 li-pol charger module with a 100mAh rechargeable battery.

I used IAR STM8 Embeded Workbench IDE and wrote a new simple firmware for the STM8S003F3P6 microcontroller which placed on the HC-12 module and is driving an Si4463 tranceiver. This new device is very simple and have no many  functions, but the result looks pretty well for this small and simple thing. Little change is needed on the HC-12 PCB to provide an I2C interface to OLED, you have to cut the line which connects GPIO 0 and PB4. Then the pins PB4 and PB5 of the STM8 chip just were directly connected to the contacts SCL and SDA of the OLED display accordingly.

Thanks for your attention!
Sorry, English is not my first language.

How it looks like can be seen on YouTube:

The new firmware for an STM8S003 microcontroller of HC-12 module.

Zip Archive - 5.77 kB - 09/19/2017 at 16:53


  • 1 × HC-12 module
  • 1 × TC4056 module
  • 1 × OLED 128x32 I2C display module
  • 1 × Li-pol 100mAh Rechargeable Battery
  • 1 × Micro slide switch on\off

  • 1
    For load the firmware you can use two golden points those are placed on bottom side of HC-12 module.
    • These are NRST and SWIM contacts. For upload the firmware an st-link v2 can have been used.

View all instructions

Enjoy this project?



Elliot Williams wrote 10/04/2017 at 19:38 point

Very cool!  I'm happy to see a project with the HC12.  Any chance of looking at the source code for inspiration?  If you use GitHub, for example, you could link it in here.  Otherwise, just putting up a zip file is better than nothing.  :)

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