My PCB business card flashes its LEDs!
Finally, I received the new PCBs from the manufacturer, after the first batch were found to be defective on track continuity (possibly due to too aggressive etching). This is a short video showing how the first one I assembled and programmed works:
Nice card, but…
The battery is an eyesore and makes the card way too thick.
Do you NEED that exact holder?
Couldn’t you have used some sort of metal springs?
Cut a hole in the card large enough for the battery, solder a metal leaf-spring on top, and another on the bottom(but use a couple of 90degree bends so that one end is brought up to the front, so that you won’t need a through-hole)
And, maybe switching that huge CR2032 (2cm diameter, 3.2mm thickness) with a CR1610 at the same time?
There are a few reasons for using the 2302, one is that I found readily available SMT mount holders for it, another is that the holder was robust enough to be mounted on the 0.6mm thick PCB and not suffer, and finally, the holder makes the battery replaceable in a hurry. I had considered soldered batteries, as you can find tiny ones, maybe in v2.
Thanks for your comments!
You can still make them replaceable and avoid making them an eyesore.
By recessing the battery into the card(one piece of metal behind it to stop it falling out the back, which also functions as the negative terminal, and one on the front to act as the positive terminal)
The way your card is now, everyone will go ‘Oooh, ah!’ and think it’s great… Until they try to store it somewhere.
Have you considered adding one of those piezo disks commonly used in watches, old ‘Game & Watch’ games and similar?
(They’re also used in those annoying digital greeting cards that starts playing awful digital mutations of popular songs when you open them.)
The cards I hand out are not populated, and I keep one functioning to show – I offer receivers the option of sending them a parts kit so they can assemble a functioning one. The problem is not so much on the battery size but the robustness of a 0.6mm PCB with such long tracks running around, it’s very easy to break them. There is also the issue of cost, the PCB alone runs at almost 4€/card (think setup fees etc. for a 100-piece run), as it is silver-plated using a high-grade alloy, otherwise the plating would oxidize and look like crap after handling and/or time, if I had to populate them all, it would mean I’d have to be even more restrictive on who I handed them out to
In any case I’ve noted all your points (the game & watch one is quite interesting!).