I’m genuinely grateful that some PCB manufacturers now offer free fabrication, because it gives people like me a chance to try making our own boards without much risk.
How this started
About a year ago, during a break, I happened to come across people making custom PCB business cards online. Around the same time, I learned about the old 5 CNY PCB prototyping offer from JLCPCB, so I gave it a try and designed a PCB business card for myself. At the time, I assumed that would probably be my one and only experiment with circuit boards.
What I did not expect was that these PCB companies would later start offering free prototyping. Now 1–4 layer FR-4 boards and single-layer aluminum boards can be made for free, with shipping included. That still feels kind of unbelievable to me. As soon as JLCPCB announced in July that free prototyping was available, I started designing a board that same night 😂
I used to think the cheapest form of personal customization was probably something like paper models. Turns out I was just ignorant—PCB is apparently the real low-cost custom-made item.
Redesigning something new
Since I’m not an electronics major, I naturally don’t know much about making serious functional circuit boards. But at least after the last attempt, I was no longer starting from zero.
This time I didn’t want to make another business card. Repeating the same thing didn’t sound fun, so I came up with a different design: a round tag with a simple line drawing of Hatsune Miku printed on it. I also put my own information on it, so in that sense it still works as another kind of personal card.
At the same time, I designed the board with a diameter of 10 cm, which means it can also work as a coaster. FR-4 has decent heat resistance, so it should help keep a hot cup from damaging the desk.
Speaking of coasters, I recently redeemed a gift through ASUS’s Tianxuan mini-program and picked a coaster. Its size actually looks pretty similar to the size of my PCB tag. Of course, a proper coaster is ceramic, while mine is still a pretty questionable interpretation of one 😂
Making my own PCB ruler
More than another name card, what I really wanted to make was a PCB ruler. The problem was that JLCPCB’s free prototyping is limited to boards within 10 × 10 cm, and a 10 cm ruler is not especially interesting.
Later I found another PCB manufacturer, Jiepei. It seems they had free PCB offers before too, but I hadn’t really heard much about them back then. Now they offer two free prototype orders per month, much like JLCPCB, and they also cover 1–4 layer FR-4 boards and single-layer aluminum boards.
The really important difference is that Jiepei allows free fabrication for boards up to 0.015㎡/pcs. In other words, the restriction is based on area rather than length and width separately. Compared with a 10 × 10 cm limit, that gives a lot more room to work with. They also offer a few more options: exposed copper pads are supported, and lead-free processing is free as well. JLCPCB doesn’t offer those options in the same way.
An area-based limit is perfect for a ruler, because a ruler doesn’t need much total area, but it does need length. So I decided to do the design in Lichuang EDA and then send the Gerber files to Jiepei for manufacturing.
At first I completely messed up the size calculation. While filling in the PCB pricing information, I was thinking about how big 0.015㎡ actually is. I absentmindedly entered 15 × 2 cm, and the system displayed a total area of 0.0150㎡. So I thought, okay, I’ll design it as 15 × 2 cm.
What I failed to realize was that the displayed total area referred to all 5 boards combined. The actual area of a single board I was ordering was only 0.003㎡. My math really is not good enough for this kind of thing 😂
I only realized the mistake after placing the order, when production had already started. At that point there was nothing I could do. That ruler design was basically wasted.
So I recalculated everything and decided to go with 30 × 5 cm instead. A 30 cm ruler is at least a proper long ruler. This time I checked the numbers carefully, confirmed that a single board really did come out to 0.015㎡, and then started redesigning it.
The annoying part of drawing a ruler
When designing the ruler, imported graphics are easy enough to use, but a ruler covered only in decorative images would be pretty pointless. Some people share their PCB design files online, and you can browse projects on OSHWHub. There are some genuinely interesting things there that can be copied directly into your own design, like protractors.
Drawing those markings from scratch is troublesome, because you have to calculate everything yourself and convert polar coordinates into Cartesian coordinates. My calculation skills are already poor, so doing that kind of geometry is really exhausting for me. Because of that, I ended up looking for ready-made designs online instead.
The only issue was that I couldn’t find one with 1° graduations. Most of what I found used 10° intervals. That was a bit frustrating, but in the end I had to settle for what was available. After finishing the ruler, I also shared the design on OSHWHub. If anyone is interested, they can take a look there. Since I wanted to make the ruler on an aluminum substrate, it ended up being a single-sided board.
Other fun things to try?
There are a lot of interesting projects on OSHWHub. People have clearly put some thought into how to get useful or amusing things out of these free PCB offers.
Besides rulers, one thing that caught my attention was a desk-mat puzzle design. If one board is 10 × 10 cm, then four boards can be assembled into a 20 × 20 cm section. With two orders, you could end up with a 20 × 40 cm desk mat, which is honestly pretty fun.
This also made me notice one of JLCPCB’s advantages: they can make green aluminum boards, and their solder mask color options are richer than Jiepei’s.
Unfortunately, I don’t know how to solder yet, so even if I had interesting functional boards fabricated, I wouldn’t really be able to use them. And if they aren’t useful to me and don’t work well as decoration either, then for now I don’t have much reason to make them, no matter how interesting the function might be.
One exception: AZPR EvBoard
There is one special case: the AZPR EvBoard (AZ Processor Evaluative Board), a teaching board used with the book Introduction to Homemade CPU Design.
What makes it memorable is that it looks adorable. Unlike an ordinary circuit board, the back side is designed to resemble a girl. Even better, the holes and traces don’t feel awkwardly forced into the illustration—they actually look like they coexist with the character design quite naturally.
The first time I saw this design was when a classmate bought the book Introduction to Homemade CPU Design. The Chinese edition uses that girl on the cover. As soon as I saw it, I thought to myself that one day I had to track down the board design.
I still haven’t read the book yet, but I’ve now found the PCB files for the board and already sent them off for production. Once the boards arrive and the semester starts, I plan to borrow the book from that classmate and take a proper look.
I did study the rough structure of CPUs before in a computer organization course, but I’ve never tried designing one myself. This feels like a good chance to learn and get a sense of what the fun of CPU design is actually like.
If anyone else wants to fabricate this board, the author shared the Gerber files for version 1.2 on Seeed, so it can be ordered directly if you’re interested. That version is basically the same as the circuit used in the book. The downside is that the power board has to be fabricated separately.
The commercially sold version is v2.0, but at the moment I haven’t found the v2.0 files or a place to buy it anywhere online.
There are sellers on Taobao offering the v1.2 board, but I really wouldn’t recommend buying from them. If JLCPCB or Jiepei will fabricate five boards for free, then reselling one for 15 CNY is pretty shameless. That said, those sellers do offer a board with components already assembled. It’s very expensive—688 CNY, which is roughly 100 CNY more than the official version used to cost, though the official one is unfortunately unavailable now. Still, if someone really wants to try the experiments from the book, buying one like that is at least an option.
What I want to do next
Next, I’m thinking about designing a Christmas tree PCB. It should probably be made of three parts in total: a horizontal piece, a vertical tree outline, and a round base. Then I want to add some LED lights to it and use the project as an excuse to finally learn how to handle a soldering iron.
If that works out, I might be able to DIY a tiny Christmas tree at an absurdly low cost (^_^)