Starry Sky PCB Optimized Version

PDF_Van Gogh Starry Night PCB Optimized Version.zip

Altium_Van Gogh Starry Night PCB Optimized Version.zip

PADS_Van Gogh Starry Night PCB Optimized Version.zip

95654

Electronic dice

An electronic die made using the air001 chip.

This is an electronic dice made using the air001 chip, intended as an alternative to physical dice for entertainment.
Project features:
1. Convenience: Compared to traditional dice, electronic dice are more portable, easier to carry and use, and less likely to be lost. 2. Randomness: It can simulate the randomness of real dice through an internal random number generator. 3. Programmability: Electronic dice can be programmed to implement specific rules or game modes. 4. Visualization: Simulates the display of results from real dice, providing a clear and intuitive experience. 5. Fairness and impartiality: Through programming, the probability of each result is equal, preventing cheating. 6. Noise-free: Physical dice are quite noisy and can easily disturb those around them; electronic dice are noise-free and can be used without disturbing others.
 
Due to an initial oversight, the reset and start buttons were reversed on the prototype; this has been corrected.
Using black 3D printing material would likely yield better results.
 
 
 
 
 

Shell.STL

Demo.mp4

Simple Code.zip

PDF_Electronic Dice.zip

Altium_electronic dice.zip

PADS_Electronic Dice.zip

BOM_Electronic Dice.xlsx

95655

MediaTek MT7628 router

This is a 100Mbps router based on the MediaTek MT7628, supporting PoE power supply. It features isolated PoE power input, supports the IEEE 802.3af protocol, and can be converted into a 100Mbps access point panel.

 
This solution uses the MediaTek MT7628 chip as the processor, and the PoE chip selected is the Nanjing Guobo WS3203
open source protocol: CC-BY-NC-SA3.0.
Configuration:
MT7628 main controller,
DDR2-128M memory
, 32MB FLASH storage,
WAN supports PoE power reception,
PoE protocol: IEEE 802.3af,
the main controller uses the E103-W20 module (MT7628 main controller)
, and the PoE isolated power controller is the Nanjing Guobo WS3203.
Note: The initial design considered adding a USB-C port for power supply, using 48V for fast charging (PD3.1 protocol), but in actual testing, the regular USB-C port cannot use 48V, and hot-swapping will cause arcing and burn the interface. I've seen 48V solutions on the market, but they might be using custom USB-C
connectors that arced during cable disconnection
, causing issues with the PoE power supply handshake process (which is similar to the PD protocol).
The E103-W20 module comes pre-installed with OpenWRT 14.07 firmware. For secondary development tutorials, please refer to the E103-W20 module datasheet. (
Mobile phone recognition of the E103-W20 module's Wi-Fi
PoE switching power supply circuit.)
 

VID_20240304_195712_1.mp4

breed-mt7688-reset38.bin

PDF_MediaTek MT7628 Router.zip

Altium_MediaTek MT7628 router.zip

PADS_MediaTek MT7628 Router.zip

BOM_MediaTek MT7628 Router.xlsx

95656

A Simple Digital Oscilloscope Based on STM32

A simple STM32-based oscilloscope for detecting and displaying waveforms, and also capable of outputting PWM square waves with adjustable frequency and duty cycle.

A digital oscilloscope is an instrument used to display electrical signal waveforms. It mainly consists of analog front-end processing circuits, microcontroller circuits, power supply circuits, control circuits, trigger circuits, calibration circuits, and other circuits.
This training camp uses a GD32 as the main controller (fully compatible with STM32F103C8T6) for DAC sampling and output of signals.
1. The power module
uses a 3.7V lithium battery and a Type-C port for power supply. A power switching circuit switches between Type-C and lithium battery power. The voltage is then boosted by a PW5100 chip before powering other components. The lithium battery charging circuit uses a TP4056 to charge the battery. Two indicator lights monitor the battery level: a green light indicates charging is complete, and a red light indicates charging is in progress. In addition to the power input circuit,
the negative voltage generation circuit


uses the XD7660 negative voltage generator to obtain a negative voltage to ensure the operational amplifier's performance in measuring negative voltages. This chip has a simple external circuit, requiring only two capacitors and a diode to operate. Theoretically, with an input voltage of +5V, it can also output a -5V voltage. Due to the chip's internal voltage drop and conversion efficiency, the actual measured negative voltage is approximately -4.3V, which still meets the operational amplifier's requirements.

2. The analog front-end processing circuit

includes an input AC/DC coupling switching circuit, an input signal attenuation circuit, and a signal conditioning circuit.
AC/DC coupling switching circuit: A 100nF capacitor is used to block the DC component. The higher the frequency, the smaller the capacitor should be; 100nF is sufficient here. For capacitor selection, please refer to relevant documentation.
Signal attenuation circuit: When measuring high voltage, the board cannot withstand it, so voltage attenuation is necessary. Here, the voltage is attenuated by 1/50. This allows us to calculate that the low-voltage range can measure -1.6~+5V, and the high-voltage range can measure -80V~+250V. Since there is no protection, it's best to avoid measuring high voltage for safety reasons. You can also change the attenuation factor by replacing the resistor.
Signal conditioning circuit: This involves analog electronics knowledge and can be analyzed using the concepts of "virtual short" and "virtual open". A voltage follower (impedance matching) and a proportional amplifier circuit are added after this, resulting in Vo = (5-Vin)/2.
 3. Comparator frequency measurement circuit:
The ADC input signal is compared with the input signal through a hysteresis comparator to achieve frequency measurement.
To enhance the circuit's anti-interference capability, positive feedback is introduced on top of the single-limit comparator to ensure signal stability within a certain range. After passing through the hysteresis comparator circuit, a square wave signal is output. The period of the input waveform is calculated using the microcontroller's timer capture function.
4. Rotary Encoder Circuit: A


rotary encoder is a special type of button. The EC11 rotary encoder used in this project has five pins. Pins D and E are similar to ordinary button pins; they conduct when pressed and disconnect when released. The remaining three pins, A, B, and C, are used to detect the rotation direction of the knob. Pin C is the common terminal and can be directly grounded.
During rotary encoder operation, there is a phase difference between the A and B signal pins. That is, a change in the signal on one pin occurs before the signal on the other pin changes, meaning the two pins do not change simultaneously. By detecting which pin changes first, the clockwise or counterclockwise rotation function can be determined.
The rest of the circuit is relatively simple and will not be described in detail here.
Next, let's look at the actual finished product .  
After measurement, the square wave bandwidth can reach 30~50KHz, making it a good measurement tool.
You can view the effect through a video.
The GD32 and STM32 source code and HEX files, as well as the BIN file, are all included below. If the GD32 software crashes when burning the HEX file, try using the BIN file instead. STM32 serial programming can be done using FLYMCU.
 

Simple Oscilloscope STM32 Version (1).rar

CH340 driver.zip

FlyMcu.exe

Oscilloscope factory firmware.bin

Simple digital oscilloscope factory firmware.hex

QQ Video 20240319233156.mp4

PDF_Simple Digital Oscilloscope Based on STM32.zip

Altium_Simple Digital Oscilloscope Based on STM32.zip

PADS_Simple Digital Oscilloscope Based on STM32.zip

BOM_Simple Digital Oscilloscope Based on STM32.xlsx

95657

Air001 Auto Downloader - Switchable Power Version

A tool specifically designed for automatic serial port downloading of the air001 microcontroller, supporting 3.3V and 5V.

I referenced Walkline's solution on the open-source platform (https://oshwhub.com/walkline/air001-auto-download-tool) 
and modified it to have a switchable power supply, making it convenient for different voltage scenarios.