Emil's Projects & Reviews: Entries Tagged black pill

STM32 "Pill" boards 13th November 2020

This is a collection of pinouts and schematics for the cheap Chinese STM32 development boards available on Aliexpress and Ebay:

DemoBoard STM32F030	$1.23
BluePill STM32F103	$1.67
BlackPill STM32F103	$2.22
BlackPill STM32F4x1	$3.70
DevEBox STM32H750	$10.92

Prices include shipping from Aliexpress and are based on buying lots of 10 pcs.

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2 comments. Tags: black pill, blue pill, stm32.

CW Keyer/Decoder BlackPill/F401 23rd March 2022

The nanoKeyer project is a CW keyer based on the Arduino platform and can be operated with a PS/2 keyboard or a Iambic paddle.

I've started my own CW Keyer/Decoder project based on a BlackPill STM32F401 module because I'm not very good at Morse code (neither transmitting nor receiving) and I wanted something more sophisticated as an aid.

By taking advantage of cheap modules available on Aliexpress I propose the following schematics for a BOM of around 15$

The design will use:

a BlackPill F401 module (which is most of the time cheaper than an Arduino board)
an I2S speaker and up to 3W amplifier (MAX98357A)
an I2S microphone (INMP441)
a 16×2 alphanumeric or a 128×64 graphic LCD
rotary encoder, buttons, switching supply, opto-couplers

Advantages:

This design will use a modern Cortex-M4 84MHz processor with hardware floating point unit and lots of RAM.
It can be a USB host so it will support modern (USB) computer keyboards. Typed keys will also be displayed on the LCD.
The LCD will allow parameter setting and the unit will operate independent of computers.
Connection and control from a computer is still possible via the USB-C connector present on the F401 module.
The CW tone will be synthesized and the speaker will generate a pure sine wave which could be directly fed to the audio input or microphone of a SSB transceiver. Attack and decay envelopes of the sound will prevent poping noises. A CW output switch is also available.
The I2S microphone will capture the ambient sound, apply a FFT transform and decode any captured Morse code (I'll probably use the second line of the display).
All the components are through-hole or modules and it will be easy to build and solder.

The project schematic

Gerber files for PCB manufacture

2 layer PCB

The STM32F401 processor CubeMX and its documentation

Components
	ARM Cortex-M4 STM32F401xC.pdf	5pcs	$17.58
	3.3V LCD1 16×2 lines	5pcs	$11.82
	or SPI LCD2 128×64 pixels	5pcs	$20.35
	I2S Microphone INMP441.pdf	5pcs	$10.04
	I2S Speaker Amplifier MAX98357A.pdf	5pcs	$12.92
	Switching Power Supply MP1584.pdf	5pcs	$3.95
	Optocoupler PC817.pdf	20pcs	$2.28
	Speaker 2W 8Ohm	5pcs	$4.68
	Rotary Encoder	5pcs	$2.88
	Switch with Caps 12×12mm	25pcs	$2.38
	USB Type A Socket	10pcs	$1.52
	PJ316 3 pin Socket	10pcs	$1.87
	PJ320a Stereo Socket	100pcs	$6.03
	PCB 1.6mm 2 layers	5pcs	$15.20
	Aluminum Enclosure	4pcs	$40.73
Total			$133.88