Create a Business Card Running Linux and Python for $20

“Hello, I am George, this is my business card.””

“Oh? Does this business card have a USB port and a chip?”

“Yes, this business card runs Linux. You plug it into the computer’s USB port, and Linux will boot in 6 seconds. Then you can log in through a virtual serial port and access the shell. It contains my resume and photo, as well as a few classic Unix games: fortune, rogue, 2048, etc., and a MicroPython interpreter!”

“That’s so cool! This business card must be expensive, right?”

“Not at all, the total cost is less than 3 dollars, feel free to take one; I have plenty more!”

This is a fictional scene I created after reading George Hilliard’s article “My Business Card Runs Linux”.

I am not very good with hands-on tasks; I can’t tinker with hardware, and connecting circuits on a breadboard is probably my limit, so I chose software development in college.

When I saw George’s business card running Linux, I was really “envious and jealous”.

This cool business card is actually a complete, minimal ARM computer running a custom Linux firmware built with Buildroot. All of this fits in 8M of flash storage, with the bootloader taking up 256KB, the kernel 1.6MB, and the filesystem occupying 2.4MB, leaving plenty of space in the flash.

George Hilliard designed and created his Linux business card himself. As an embedded engineer, he enjoyed the process, and the biggest challenge was finding the cheapest components.

The final result is that the total cost of this business card is quite low:

See that F1C100s? It was bought from Taobao. I searched for it on Taobao, and indeed, it is currently only 6 yuan.

Hardware Section

The key “architecture decision” was the processor. After extensive research, he chose a SoC produced by the Chinese company Allwinner Technology: the F1C100s, which is quite cheap and includes both RAM and CPU.

Other components were purchased from LCSC (an online electronic component store).

George found the F1C100s on Taobao remarkably cheap, so he bought a large bag of them:

George used the JLC website to make the PCBs (printed circuit boards). This is a self-service website where you just need to upload your design files and wait at home. He made 10 PCBs for 8 dollars.

I looked it up, JLC stands for Jialichuang, which is also a Chinese company!

Software Section

Porting Linux to Allwinner’s F1C100s from scratch is not easy. Fortunately, there is a programmer named Icenowy in China who maintains a version supporting F1C100s on GitHub:

https://github.com/Icenowy/linux. Interested students can check it out.

The chip is made in China, the PCB is “printed” in China, and the software is developed based on a Chinese development version, so it seems this business card is rich in Chinese elements!

George modified it, adding some drivers (pin controllers and clocks), and upgraded the Linux version from v4.9 to v5.2, ultimately creating a Linux environment on the business card:

https://github.com/thirtythreeforty/linux

Finally, George also provided a circuit diagram. Interested students can refer to it to make one. In China, there is the advantage of being close to the source, but I can’t manage it; just looking at these diagrams gives me a headache.

References:

https://www.thirtythreeforty.net/posts/2019/12/my-business-card-runs-linux/

https://www.thirtythreeforty.net/posts/2019/12/designing-my-linux-business-card/