Simple thermal imaging based on Taishan Pi

Demo video released: BV1PS411F7kT

For the specific tutorial of the small mobile phone, please refer to the official document of Leadron: [Fat Girl Mobile] Practical Project Information

Part 1: 3.1-inch mipi LCD screen expansion board

Based on the first training camp of Taishanpi, a 3.1-inch screen expansion board was added on the basis of Taishan pi embedded Linux development board (the audio seat was later changed)

In order to provide a suitable backlight current, an I2C-PWM circuit is designed on the board.

As well as the same backlight driver of Taishan Pi.

Four 0 ohm resistors are placed to facilitate switching the backlight source (note, these four resistors cannot be soldered at the same time, as the actual measurement of the group friends will lead to the failure of the Taishan Pi)

Points to note:

1. Do not solder the resistors marked with NC.

2. After the seat is welded, check whether there is virtual soldering and tinning.

3. Check whether there is a short circuit in the power supply network before powering on.

4. Both lines are in the same direction.

Problems encountered:

1. The backlight boost circuit diode was selected incorrectly, it should have been 3A, but it was very hot after changing to 1A, and finally 3A was used.

2. If you choose the wrong speaker base, you should use the opening upwards.

3. The touch seat is welded crookedly, resulting in poor contact after installing the shell, and there is no touch.

Part 2: External Hikvision 4117 thermal imaging module

Designed a backplane for fixation for Hikvision 4117 (40PIN receptacle has no actual electrical connection)

(Refer to the shape of the Hikvision thermal imaging module TB-4117-3/S to transfer the parameter backplane, so you won't put the file, you can enter the group if you need it)

(The screws are m2*6 found casually on Taobao)

And a USB adapter board:

It is used to convert the interface of 4117 into a USB male connector and plug it directly into the Taishan pi.

The UHikCamera app that is circulating on the Internet is used here, and it can be turned on by default to automatically display the thermal imaging picture when Taishan Pi is turned on.

Part 2 Questions:

1. The opening position of the back plate is incorrect, resulting in a screw that cannot be screwed in.

2. The USB adapter board and the self-made cable are too prominent, not very beautiful (to be optimized)

Part 3: Software & Drivers

About setting up the environment:

I still remember the first problem I encountered at that time was the compilation environment configuration, because of copyright issues, Wu Gong used the VirtualBox virtual machine during the live broadcast, and the download and installation were very smooth when I followed the operation, and then I didn't know why I was stuck in file sharing, and there was no progress in tossing for an hour, so I had no choice but to ask for help in the group, and asked Wu Gong to help me remotely for more than ten minutes, and finally confirmed that the problem was that the file directory was set incorrectly, and there were two more layers...

About system compilation:

Because there were too many bugs in VirtualBox and the performance was not very good, I switched to WSL for development. But WSL is not a fuel-efficient lamp, with Ubuntu22.0.4 run based on Ubuntu18.04 tutorial reported a bunch of dependent version of the wrong ERROR, all kinds of posture Baidu for a long time and was unable to solve, had to download Ubuntu18.04, and dealt with a lot of bugs, engaged in a week to compile successfully, the remaining space of the hard disk --, the remaining life--(after learning docker to compile successfully in 22.04)

Common Linux commands:

This impressive point is patching.

In a live broadcast, I heard Wu Gong say that the training camp will use a 3.1-inch screen and then decisively placed an order,At the same time, I also placed an order for the expansion board drawn by the big guy in the group,Soldering went well,But there was a problem when using the patch provided by the group boss.,No matter what, it was an error.,After that, I deleted the library several times.,Reset it to zero repeatedly.,Manually replaced a bunch of files to get it.

About the Device Tree:

As far as I understand it, it's a structured configuration file that can be used to configure the parameters of the driver.

About the screen driver:

I've always heard rumors that the MIPI screen is difficult to light up.,But after the actual contact,It feels okay.,The main thing is to write the command and timing in the device tree according to the manual.,There's nothing particularly difficult to understand.

Due to various reasons, the EDP screen was not chosen as the main learning goal of this training camp, and next time it will be ~

About Touch Drivers:

I made a logic analyzer with the Raspberry Pi PICO and grabbed the touch signal.

Compared with ordinary IIC chips, the touch chip has more INT signals, and its main function is to notify the main controller to start an interruption and receive and process touch data in time to prevent operation jamming.

TODO:

1. Find a suitable animation to replace the boot animation.

2. Try to compile the Linux driver of the 3.1-inch screen (now only Android)

ChangeHistory:

May 31: The hole in the heat sink of the shell is opened, and the model file is placed in the attachment~

September 22: A color silkscreen version was added, but the microphone didn't work very well.

November 16: The microphone part was modified, the no-copper pour area and separate grounding were added, and the measured recording effect was significantly improved to reach the usable state.