Folk and a master “haunt” :

A bicycle code watch made by a “tech geek” became popular in station B, attracting more than 200,000 onlookers in just a few days!

Speed, distance, time, calories, course display of record function needless to mention, also can display latitude and longitude and altitude.

It also comes with an offline map that shows you where you are and where you are riding in real time:

It can also be measured on cars and high-speed trains!

Switch the interface to check the system data such as power, cycling records, GPS positioning and sensors, which is quite smooth:

Look at the details, but the UI design is more advanced than many code watches on the market! (Jiaming: Why don’t you just give me your ID card?)

If that had told me it was a brand and not homemade (except for the obvious shell), I might have believed it.

Users of Respect also praised it for exploding those watches with outrageous premium prices:

“Too complete”, do you want a link?

Good guy, even Zhihui Jun was attracted (later Jiaming also appeared in the comments section “from the black”, see the following article) :

Aye? Zhihui Jun’s true bicycle and this code watch can be used together?

In addition to being very popular on The site B, this project also made it onto the GitHub hot list today:

And according to net friend rough estimate this code table hardware cost is probably less than 300, so excellent it, is how DIY come out?

How to DIY a bicycle code table

The schematic diagram of X-Track software architecture is as follows: It consists of HAL, Framework and APP, with Framework as the core.

HAL layer is responsible for the underlying chip driver and sensor raw data acquisition;

The Framework includes three modules, which are responsible for graphics rendering, page lifecycle management, and message distribution processing.

The message framework module provides data distribution and processing.

The sensor data received by HAL layer is published by subscription publishing mechanism and forwarded to corresponding subscribers for data processing.

Take GPS as an example, GPS data processing node reads satellite data once every second, and then publishes, and the message framework pushes GPS data to subscribers.

Subscribe to GPS data in the motion data processing node. After receiving GPS data, the motion data processing node calculates the total mileage, average speed and other information according to GPS data. In the dial page, pull the motion data node information and display it in the dial page.

Ps. The map software is GPXSee.

There are seven main steps to achieve this:

1. First, hardware design.

PCB board circuit design with AD (Altium Designer) :

Circuit diagrams and PCB files can also be viewed in detail on GitHub.

2. Then there is the UI design that has been praised by everyone:

The design software is Adobe AI.

3. Then design the shell on 3ds MAX:

4, and then the software design:

Programming language is C++ :

5. Use the simulator to simulate the effect directly on PC.

The graphic interface of code table adopts the free and open source GUI graphics library LVGL.

The finished product uses many of the basic controls provided by LVGL, such as the Line control for the track display on the map page, the Image control for the map display, and the button control for the page switching selection on the dial page.

6, debugging debugging, no problem can be compiled and downloaded.

I’m using Keil here.

7. Finally, the final program is burned to the microcontroller (AT32F403ACGU7) for running, and then connected to ST-link for debugging.

Success!

In addition, many people may not know that the AT32 series MCU used by UP is a domestic design (Chongqing Yatli), which can replace STM32F103 series of STMICROELECTRONICS, with higher main frequency and larger RAM.

All hardware configurations are as follows:

With 32GB of memory, it’s no problem to store a 1GB map of Beijing.

In addition to the features mentioned at the beginning, it also supports map scaling, step counting, export track in standard GPX format, RTC automatically calibrates according to GPS, save data automatically in case of power failure (JSON file), but the battery life is 4 hours (continuously working, always on screen)…

The hardware and software parts of the entire design are open source.

Even the “rival” Jiamin gave a thumbs-up

How’s that？ Have you learned (failed)?

Many onlookers feel that such a UI appearance, rich function of the bicycle code watch if there really can be manufacturers to cooperate in the production, then there are these products jiaming what matter

?

Someone wrote in the comments section @Garmin, which actually led to it: “Great! Give x-Track a thumbs up even for a” competitor “.

Someone also calculated an account, in a treasure according to the tutorial to buy these accessories need a total of less than 300 yuan, than jiaming thousands of prices is much cheaper (although the battery life is a little lower).

Netizens urging mass production is really very, very many, but really to commercialize, in addition to the battery life, some cycling enthusiasts think it is necessary to support Ant +, pedal frequency, heart rate, power equipment connection, dustproof and waterproof functions, and consider the current screen visibility in the sun and other issues.

I wonder if X-Track will continue to be added or improved in the future.

After all, UP, who graduated from an electronics and information major, says he is half a cyclist.

Finally, in addition to this fantastic bicycle watch, he has also made a smart watch and a remote control for a model airplane using STM32.

Video link: www.bilibili.com/video/BV1GB…

Open source: github.com/FASTSHIFT/X…

The software design is introduced: mp.weixin.qq.com/s/rCtmW7taw…