Summary
This article designed the schematic diagram and PCB of AHT20 with reference to the AHT20 manual, and added STM32.
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Introduction
The previous blog introduced the adoption of the data collection of the AHT20 temperature and humidity sensor based on I2C , simulating I2C to collect temperature and humidity, and also drawn the STM32 minimum system. Today I want to talk about how to add the AHT20 schematic diagram and PCB to the STM32 minimum system.
1. Introduction to AHT20
AHT20 is a MEMS temperature and humidity sensor with I2C interface produced by Aosong in China. The number of ADC is 20Bit. It has the advantages of small size, high precision and low cost.
Because AHT10/15/20 has the characteristics of localization, small size, high precision, low cost, etc., it can replace DHT11/DHT12/AM2320/SHT20/SHT30. The price of a single chip is ￥2~3, and it is small and easy to be embedded in the product. . For details, please refer to the previous I2C-based AHT20 temperature and humidity sensor data collection .
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2. Download relevant information
Enter the official website . Download the product manual on the official website:
Relevant data can be obtained (partial screenshots):
With the product data, you can create a package!
Three, AHT20 package design
step1: Open the project and add PCB package
Change the name to AHT20.
step2：Packaging is the most important-Design pad
According to the above figure, the pad is 长0.55mm，宽0.4mm，上下相距1mm，左右相距2mm, design pad
The pad should be set to a square shape with the following size
ctrl+m measure the distance shift+ctrl+g to set the grid, I set 0.01mm to facilitate adjustment, then copy and arrange the position
step3: draw silk screen
There are skills in drawing silkscreen, first place one, set as follows
Then, copy and paste the center point to get the result
Set the pad number
Finally, a flag is set to indicate the orientation of the component
step3: Set up the 3D model
Place -> 3D component body
Adjust the design 3D model according to the size
Make the following settings
The final result is as follows, then type in English to 3，shift+鼠标右键view the 3D body
Finally save
Three, AHT20 schematic design
step1: add AHT20 to the component library
step2: Place the rectangle
step3: add pins
Note that the cross side is outside, TAB key to modify the name and number
Set as follows
step4: setting, packaging
Double-click AHT20 in the schematic library and make the following settings
Add package in the lower left corner:
The final result is as follows, save it
Fourth, modify the general schematic diagram
step1: Reserve a place in the original schematic
step2: Select AHT20 in the schematic gallery and place
step3: select components, and then connect
Find the corresponding component in the following library
The final connection is shown in the figure:
step2: get the following schematic diagram after labeling
inTools-Labeling-Mandatory labeling of all schematics, labeling
The final schematic is as follows:
Five, draw the PCB
The final drawing of the PCB is shown below, and the intermediate process is introduced in the previous blog post . You can understand by yourself.
After typesetting, the final drawing is as follows:
Will be AHT20placed in the upper left corner.
Then the copper had to be laid as before, and then the electrical appliances were checked and so on, so that the entire operation was completed.
Six, summary
This time, according to the reference manual of AHT20, I have carried out the same principle diagram and PCB design, and I am more familiar with the whole process, which is a good exercise.