Printed circuit board “enterprise playing cards” are fashionable amongst engineers, with every rendition having a singular take. Generally they’re purely ornamental, with intelligent makes use of of solder masks, silk display, and copper layers to realize an attention grabbing design. And generally, they comprise low-cost intelligent circuits. So, it’s fascinating when a brand new thought comes up, like this one. Dennis Kaandorp’s PCB enterprise card has an built-in battery holder, an LED matrix, and a microcontroller.
Kaandorp’s card measures the identical dimension as a typical bank card. On the entrance are 42 dual-colored LEDs, 4 push buttons, and a microcontroller. The again has a QR code that hyperlinks to Kaandorp’s LinkedIn profile. However probably the most modern function is on either side: the battery clip holder.
PCB Cutout for CR2032 Battery (📷: Bigfoot Creations)
PCBs are usually made out of FR4 and are considerably stiff. Nonetheless, this design makes use of a cutout to realize a versatile arm design. Consequently, the arms are giant sufficient to carry a coin cell CR2032 in place but in addition versatile sufficient to switch the battery! And for security, Kaandorp even included a MOSFET for reverse polarity safety.
The LED matrix has an intriguing design alternative as nicely. Sometimes a matrix like this one would use the Charlieplexing method. A Charlieplexed matrix would solely want 10 GPIOs to regulate 42 LEDs on this case. Nonetheless, there are some trade-offs with that sort of matrix, comparable to restricted voltage obtainable for the ahead voltage drop and sophisticated routing. So, Kaandorp adopted a hybrid strategy of Charlieplexing and conventional matrix, which required solely three extra GPIOs.
LED Matrix Demo (📷: Bigfoot Creations)
Why 42 dual-color LEDs? Kaandorp picked the worth as a result of it’s the identical variety of components needed for a Join 4 sport board.
A Microchip ATtiny1616 drives the matrix and reads the enter buttons. These 8-bit microcontrollers have as much as 22 GPIO strains which labored out nice on this PCB enterprise card design that wanted 17.
The assembled value is $5.12 in prototype portions and $3.50 in portions higher than 25. You’ll be able to obtain the design information from the hyperlinks on the backside of this Bigfoot Creations weblog publish. You’ll, in fact, need to change the contact data to yours!