Spectrum light based on ESP32

Open source project-spectrum light.7z

BOM download

62067

Portable mini heating table V2.0

Introduction: The PID temperature control heating stage based on STM32F103C8T6/C6t6 is very convenient and easy to use. The new version has a self-made menu UI, which can adjust various parameters through the encoder. It is more practical than the first version and also enhances stability. ,Multi-PD protocol support.

 The second version will be more practical, beautiful and stable. Similarly, all modules in the second version will be open source and can be customized, including STM32 master control and PD protocol modules. The second edition will also have more comprehensive information.
The development environment
uses KEIL5 and is developed based on the STM32F103C8T6 or C6T6 standard library (in actual testing, this version of the program is compatible with C8T6 and C6T6A).
Progress update:
March 15, 2022. 
  The program framework has been written, and the menu and UI framework have been built. The first version of PCB is being drawn. On
March 20, 2022, 
  the fast charging protocol module based on CH224K has been experimentally completed. Can output 20v, 15v, 12v, 9v voltage.
On March 31, 2022, 
  the PCB and program were basically completed. Start sample testing. The PCB has been received
on April 5, 2022 
  , and testing of stability and actual usage has begun.
  The basic test passed, there are no major problems in the program, some minor bugs have been solved, the PID has been roughly adjusted, and the OLED refresh rate has been optimized to make the animation smoother.
  Optimized the reading of the encoder, making the reading more accurate and stable. In terms of hardware, due to the difficulty and cost of production, the next board drawing separates the MCU main control and the board and uses pin headers to connect them. This can reduce the difficulty and cost of production.
  After half an hour of constant temperature testing at 200°C, the MOS was about It is 40+ degrees, and LDO generates a lot of heat, about 60 degrees. Heat dissipation needs to be enhanced in the future. The MOS tubes should be managed together to reduce heat generation. The LDO is equipped with a heat sink.
On April 6, 2022, 
　the new PCB has been drawn, and this version is expected to be a stable version. It solves the production difficulty, cost and heat dissipation issues. The 3D shell drawing is completed.   The v2.0 PCB has been verified on
April 10, 2022  , and the 3D shell is on the way. Officially released on April 17, 2022  ! ! ! ! Summary MCU: STM32f103c8t6 (or c6t6A)  Power supply: PD protocol includes 20v, 15v, 12v, 9v (20v is recommended) Chip: CH224K Control: Encoder SIQ-02FVS3 Display: 0.96-inch OLED (IIC) Heating plate: Aluminum substrate (approx. 6.8Ω) Temperature detection: K-type thermocouple + MAX6675 Function introduction The heating stage controls the temperature through PWM pulse width modulation. Main interface: (1) Display parameters: The upper left corner displays the current temperature, the thermometer icon on the left represents the current temperature level, the battery icon represents the current power supply voltage, and the right side is like a pull cord for mode switching display. The lower slider and the temperature on the right are to set the target temperature. (2) Control: You can set the target temperature by scrolling the encoder left and right, and press the encoder to switch to the preset temperature mode with one button. Menu interface: (1) Voltage: Control the power supply voltage. (2) Temperature: Set the temperature step. (3) Setting: Set the temperature of the three modes. (4) Personalization: Not used yet. If you have any desired functions, you can put them here. (5) Return: Return to the main interface. Demonstration video (if you think it is good, please like and vote, you know~) Portable Heating Table V2.0 Open Source Mini Digital Display Heating Table_bilibili_bilibili The overall appearance of the 3D shell can be made of nylon or ABS, I am The nylon material used is made by Jiali Chuang. The texture is really good. The project has been successfully exported. For details of the PCB project file, please see attachment 2. Then the PCB plate making file and BOM have precautions  in attachment 1 (1) The mos tube generates less heat. , you don’t need to install a heat sink (add it if you can), LDO generates a lot of heat, so you need to install a heat sink, and plate the window part with solder to enhance heat dissipation. (2) The aluminum substrate is conductive, so during production, be careful not to contact the two wires connecting the aluminum substrate with the aluminum part of the aluminum substrate. (3) Pay attention to the positive and negative polarities of the K-type thermocouple. (4) Be careful not to use the heating table at high temperature for a long time. Generally, 200 degrees is enough to melt tin. In actual tests, there is no problem in continuous use at 200 degrees for 20 minutes. (5) Pay attention to distinguish the 8M crystal oscillator type of the STM32 core board. If it is a passive crystal oscillator, the new STM chip may cause the passive crystal oscillator to not vibrate and not work properly (of course there is no need to buy a brand new one, the new one is too expensive. Buy a refurbished genuine c6t6A for only 7 yuan each) (6) The screws and studs used in assembly are all M2 models.

































 
 

Portable heating table.zip

PCB project file.zip

62068

Buck-single-turn dual power strip

Introduction: During the preparation for the electronic competition, I accumulated some proven power boards. This time I open sourced two single-turn dual power boards, one of which can output 3V3 with high current and low ripple.

Module 1: TPS5450 is a 5.5V to 36V input 5A 500kHz buck converter. This power board supports a maximum input of 36V (pay attention to the capacitor voltage resistance selection), and is a single-power to dual-power adjustable output power module.
 
 
Module 2: MPM3620 is used as the 8-18V input of the step-down part. After step-down, it outputs plus and minus 5V, plus and minus 1A through two LDOs. The power module has strong load capacity, extremely low ripple, extremely low noise, and is fast. Transient response.
 
Module 3: Using MPM3830 as the step-down input, the input voltage is fixed at +5V, the output voltage is 3.6V, and 3.3V is output through the LDO. Mainly used for chips that require large current and low ripple, such as AD9854 (DDS). The LDO model is MAX8556, which is an ultra-low input voltage regulator that can output a current of 4A at a voltage drop of 100mV.
 
   For electric competition use, generally speaking, it does not require too much current. It is mainly used to convert single power supply to dual power supply to supply power to dual power supply op amps, etc.
(In preparation for the provincial competition, I will open source some modules during the break. I will sort out the information after the provincial competition and open source some ADC, DAC, and DDS. It should be a series.)
 

62069

Open source wearable watch (including firmware, schematics and 3D printing diagrams)

This smartwatch can measure linear acceleration, rotational speed, heart rate and SpO2 (oxygen saturation) of the hand

Open-Watch is an open source smartwatch project developed by B.Sc. This smartwatch can measure linear acceleration, rotational speed, heart rate, and SpO2 (oxygen saturation) of the hand. All this data will be processed by the STM32 processor with ARM Cortex-M core.
MPU6050 is used for IMU purpose, using Kalman filter to reduce noise effects and extract clean data from sensors (3-axis linear acceleration, 3-axis rotation speed and 3-axis rotation angle).
The MAX30102 is a sensor for healthcare purposes that simply reads raw data and moves the process to a smartphone.
Open-watch will send this collected data to a smartphone via a Bluetooth module. On the smartphone side, the Android app reads the data from Bluetooth and processes it. For healthcare applications such as heart rate and SpO2 analysis, ML-based algorithms are used to extract these parameters from the raw data read by the pulse oximeter sensor.

open-watch-master

62070

Teacher ChaN’s headphone amplifier design

FatFS author ChaN teacher open source design

Teacher ChaN’s headphone amplifier design

Teacher ChaN’s headphone amplifier design for reference

hpa_ctrl

Create documentation

62071

electronic