Well, my first attempt at assembling bcard was a complete failure. But, ultimately, I learned a way that this won’t work and have some ideas for how to modify the design.
My idea was to drill slots for each of the 4 LEDs so that they would be mounted sideways and cut out a hole for the watch battery. Unfortunately, the slot drilling was really messy and non-repeatable. It also required a lot of manual filing. Yuck:
It would be nice to mill slots, but mill bits are expensive and MITERS doesn’t have an unlimited budget, so I’d rather not grind down a ton of mill bits. A friend suggested slicing into the corners of the card to make a slot for the LED. That’ll make routing a lot harder (maybe impossible?) but it will be feasible to install the LED that way.
However, that still doesn’t solve the fact that it’s basically impossible to solder to the side of a surface mount LED. I’m very much stuck on what to do there.
I didn’t think through the battery holder very well and couldn’t find any sheet metal, so I improvised something out of wire. It’s cute, but the battery connector needs serious revision. I have some new ideas in my head, but I’ll need to buy some thin sheet metal first.
Oh well, now I know how to not make a PCB business card… back to the drawing board. :/
Finally, I got a chance to try etching a bcard board using MITERS’ awesome PCB etching process. The results were absolutely fantastic. Here are a few photos from the process:
The key thing that made this possible was the laminator, which evenly applies a coating of heat to transfer the toner cleanly and without smudging.
There was only like 1 tiny length of trace that didn’t transfer, so I cleaned that up quickly with a pen.
After washing off the paper, I let the PCB sit in the agitator for about 15 minutes, checking it every 2 or 3 minutes to make sure I wasn’t over-etching.
The results were almost flawless. There are a couple of weak-looking traces on the edges, but I should be able to clean those up for the next iteration by making them much thicker (it’s harder to transfer traces on the edges). Overall, though, it was basically painless to etch 10 mil traces with this process.
Next up, I’ll be attempting to solder and program the boards… Oh yeah, I need to actually write the firmware now.
I have been toying around with some ideas for PCB business cards. I wanted something cheap, clever, and not gaudy. I also wanted to make something that I could potentially etch myself to save on cost. What I’ve come up with so far is bcard. In addition to having my name, contact information, and QR code linking to my website, I designed a simple capacitive touch sensor scheme whereby pressing your finger on the button will make the LEDs located at the corners of the card light up. These are blue LEDs, so I’m actually thinking of inverting them so that they point into the PCB. As a result, the PCB should actually fluoresce. But that might not work… IDK.
Here’s my initial design. It uses an ATTiny10, a small transistor, 4 LEDs, a cap, and a resistor. The cap is probably unnecessary. There’s also two pads which I’ll probably make generate signals or something fun. The battery holder isn’t showing up correctly, but basically it’s just two pieces of metal that will sandwich the battery, which fits fully flush in the board.
I’m going to try to etch it soon and see how it turns out. It might be a total disaster, but I’m hoping otherwise.