STM32F407-RT-THREAD Development Board

PDF_STM32F407-RT-THREAD Development Board.zip

Altium_STM32F407-RT-THREAD development board.zip

PADS_STM32F407-RT-THREAD development board.zip

BOM_STM32F407-RT-THREAD Development Board.xlsx

94564

Retro Industrial Style Clock with Glow Tubes—Based on ESP32

Based on the ESP32-wroom glow tube clock design, it uses inexpensive QS30 glow tube bulbs, keeping costs low. It features a wooden casing, integrated boost module, and network-connected automatic time synchronization.

This project has not yet been prototyped and verified; please proceed with caution!
 
A while ago, I was obsessed with retro industrial design. Seeing the neon tube clock design by the master OMNIXIE, I was instantly captivated and began studying the working principle of neon tubes. After three nights of intense study, I had an epiphany and began designing my own neon tube clock.
Neon tubes are considered rare antiques these days. I vaguely remember seeing one in the rural power station in my hometown when I was very young. The moment it automatically refreshes from 0 to 9 to prevent cathode poisoning is probably its most beautiful and cyberpunk moment.
 
Struggling with my modest budget, I chose a relatively inexpensive neon tube this time: the QS30-1 neon tube, made in Nanchang. The SZ-8 tube from Universe can also be used. The price is relatively cheaper than other stock, around 35 RMB each. Other tubes like the IN-18 are overpriced on Xianyu (a second-hand marketplace) because of the designs by these masters, and they immediately talk about nostalgia and retro style; if you say it's 30-year-old stock, they'll get angry.
 
For the main controller, the inexpensive and reliable ESP32 is the best choice since network-connected time synchronization is required. It also supports Arduino and has sufficient performance.
 
The glow discharge tube requires a power supply of around 150-170VDC. The board integrates a MAX1771 boost converter, with the input power coming from a 5V USB Type-C port. Two Type-C connectors are shown on the board, one on the side and one on the back, for easy selection of enclosures. The high-voltage switching scheme uses the traditional HV57708 64-channel shift register, saving many I/O ports.  
 
As shown in the diagram, three 90-degree buttons are provided at the top, which can be connected to buttons on the enclosure for controlling time adjustment, RGB settings, and other functions, or can be customized.
Next to the buttons is a GH1.25 3-pin connector, which is the ESP32's touch I/O port. Originally, it was intended to connect to the metal buttons on the enclosure for touch buttons, but the enclosure wasn't designed that way. Those with the necessary communication skills can design their own enclosures to modify them for touch buttons.
The leftmost connector is a debugging interface, which also serves as an expansion interface. It has reserved I2C, UART, and analog ports for future expansion with lithium battery modules, freeing it from USB limitations.
 
 
I've hidden a few little surprises; the back is practically bare, so I felt compelled to draw something.
 
The board includes an RTC clock, intended for calibrating the time each time the computer is powered on, and not connecting to the internet at other times.
 
It also thoughtfully includes a radar sensor switch interface for detecting the presence of someone. This way, the glow tubes only light up when someone is near or constantly nearby, saving power and, more importantly, significantly reducing the glow tubes' operating time and lowering the probability of glow tube poisoning, extending their lifespan by several years.
Of course, I mainly like seeing the clock and the instantaneous 0-9 refresh of the tubes – that's a bit too electronic, so I need to look at it more often.
 
The board also features four RGB LEDs, placed under the bulb base for more color. However, I personally don't like RGB clutter, so whether to add them is entirely up to personal preference. There's also a small buzzer on the board for hourly reminders, and it can also be set as an alarm.
It's important to note that the glow tube should not be directly soldered onto the PCB. You need to purchase a pin header or an integrated lamp holder for soldering. My design uses a base like the one shown below, which is readily available and inexpensive on Taobao. Then, insert the glow tube into the base for easy replacement if it breaks. After
 
all this hardware talk, guess what? I haven't written any software at all! (hands on hips). It's not intentional; I changed jobs after designing it and was too busy, so I'm leaving it for now and will work on it later when I have time. Those who can't wait can search online for other open-source solutions. There are quite a few that use ESP32 for glow tubes; you can modify them to use them.
 
I've also attached my own wooden casing design; you can easily find a machining shop on Taobao to make it—it's not complicated. I have two designs, both attached. One is designed using Fusion360; you can check the online preview before deciding whether to use it.
 
Casing online preview: Glow tube clock overall design preview.
Another square box: Another casing design for the glow tube clock.
 

Glow tube clock design solution v1.zip

Glow tube clock design scheme V2 .zip

PDF_Glow Tube Retro Industrial Style Clock—Based on ESP32.zip

Altium_Glow Tube Retro Industrial Style Clock—Based on ESP32.zip

PADS_Glow Tube Retro Industrial Style Clock—Based on ESP32.zip

BOM_Glow Tube Retro Industrial Style Clock—Based on ESP32.xlsx

94565

SA568AD-PLL-demod

SA568 150MHz FM/FSK Demodulation Phase-Locked Loop Module

The NE568/SA568AD is a high-frequency, high-bandwidth phase-locked loop (PLL) FM/FSK RF signal demodulation module
with a maximum operating frequency of 150MHz. A maximum demodulation bandwidth of 10MHz is recommended at an intermediate frequency (IF) of
70MHz. It can be used in conjunction with a 70MHz IF crystal filter, offering significantly better performance than typical hand-made LC bandpass filters.
It can be used for various RF problems in electronic design competitions, wireless audio/video demodulation and reception, satellite communication, etc.
The center frequency and demodulation bandwidth can be adjusted via potentiometers and changes to peripheral loop filters.
The high-bandwidth mode is suitable for demodulating video signals. When demodulating narrowband signals (such as FM broadcasts) with a 10MHz bandwidth, the signal level may be too low. For
demodulating narrowband signals, it is recommended to modify the circuit to use a lower total bandwidth.
For specific calculation formulas and applications, please refer to the chip datasheet.

PDF_SA568AD-PLL-demod.zip

Altium_SA568AD-PLL-demod.zip

PADS_SA568AD-PLL-demod.zip

BOM_SA568AD-PLL-demod.xlsx

94566

Design of a high-precision phase difference measurement circuit based on FFT and STM32

Frequency and phase difference measurement development board

Two signals are acquired at regular intervals by pa5 and pa6. Once the threshold is triggered, the data is immediately moved to a memory array. The discrete-time signal FFT is implemented by DSP library functions, and logic functions are written to extract the spectrum information.

PDF_High-precision phase difference measurement circuit design based on FFT and STM32.zip

Altium: High-Precision Phase Difference Measurement Circuit Design Based on FFT and STM32.zip

PADS: High-Precision Phase Difference Measurement Circuit Design Based on FFT and STM32.zip

BOM_Design of a High-Precision Phase Difference Measurement Circuit Based on FFT and STM32.xlsx

94567

ESP32-PICO-V3 Bluetooth Mouse

This project uses the ESP32 V3 control chip and the MPU6500 as a gyroscope. The buttons are used as the left and right mouse buttons, and the Bluetooth connection is handled by the main control chip.

This project utilizes the ESP32 V3 control chip and the MPU6500 as a gyroscope. Buttons are used to act as the left and right mouse buttons, with Bluetooth connectivity handled by the main control chip.
 
Signals are received via a ceramic antenna, filtered by a π-type filter, and then sent to the ESP32 for data processing.
A TP4056 charging management chip charges the lithium battery and stabilizes it at 3.3V to power the circuit.
 
The MPU6500 provides 3-bit attitude sensing, which is then sent to the main control chip for processing. This simulates a mouse pad on a flat surface,
 
with two touch buttons acting as the left and right mouse buttons.