Matrix backpack was a fun design project

[Greg] is really working on a small scale with his LED Matrix backpack PCB. It’s a toy that he designed as an activity. He constrained himself to a board which would exactly match the outline of an 8×8 bicolor LED matrix package.

What you see here is the side of the PCB which will be facing the underside of the LED dot matrix module. Let’s call this the top of the board. The underside has a CR2032 battery holder which provides enough juice to run the display. Since the matrix is bi-color there’s a slew of pins to drive. [Greg] uses three shift registers for the high side, and sixteen N-channel MOSFETS for the low side. He’s chosen an MSP430G2201 microcontroller which has a nice sleep mode for power conservation. It has no problem driving tri-color animations as seen the clip after the break, but also has an unpopulated clock crystal footprint if you wanted to use it as a timepiece.

Despite the small footprints and cramped board [Greg] still hand soldered all of the components. He even posted a time-lapse of the process in the page linked at the top.

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Upvote/Downvote cards

Next time you throw together a talent show consider using these cards for up and down voting. [Frits Rincker] came up with the idea over the weekend based on the like and dislike buttons of Facebook. They consist of some foam board with LEDs in the outline of a hand. He built a switch which completes he blue circuit for the thumb’s up and a red circuit for thumb’s down by using a weight that slides freely in a channel, with a reed switch at either end. We’ve embedded the video after the break for you enjoyment.

Oh, and in case you were wondering; Hackaday likes this.

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FPSLIC powered LED matrix

[Mathieu] built this display in hopes that he can play pong on it. You can imagine the headache that awaits when trying to figure out how to drive the 6144 bi-color LEDs. I must have worked out because the thing looks great in the video after the break. The solution he chose was a bit unfamiliar to us though. He used a Field Programmable System Level Integrated Circuit produced by Atmel, or FPSLIC. This is a kind of mash-up of components we’re more accustomed to.

The AT94K is a single chip that houses an 8-bit AVR microcontroller, and FPGA, and SRAM. This project uses that FPGA to handle the multiplexing of the display via code written in VHDL. The AVR core receives data via a USB port, stores two images in the SRAM (one for each LED color), and then outputs it to be drawn on the display. On second thought, this project sounds like fun and it’s a great way to get start learning that VHDL you’ve been putting off. Continue reading “FPSLIC powered LED matrix”