As you know, my Wyolum buddies and I partnered up with SeeedStudios to make a really cool e-paper badge for the Open Hardware Summit which took place last week. We wanted some cool ways for people to customize their badges. Justin created a great simple program for converting images (wifit.py) and I leveraged that software to create a photobooth.
Photo by Addie Wagenknect
My friend Michael Castor at Makershed built a cool tablet from the Raspberry Pi, and he told me about the nice 10.1″ LCD display and HDMI adapter he found from Chalk-elec.
I ordered one, and started figuring out how to put the whole thing together. I also got a big red button from Adafruit. I have been playing with the Raspberry Pi camera and it’s perfect for embedding in a project like this, even though the software is a bit primative at this point (no video for linux drivers, etc.) I used our own AlaMode to read the button and use one of our WS2811 arrays to do a visual countdown before taking the picture.
I’d never really designed anything for laser cutting, and this was my opportunity! I used Inkscape, with the T-slot extension written by Justin. I got the box cut at Einstein’s Workshop (a family oriented makerspace in Burlington, MA.)
Next, I laid out the components. The trickiest parts were the LVDS cable (though it’s pretty generous) and the Raspberry Pi Camera flex cable.
One really sweet thing about the Chalk-elec hdmi adapter is that you power it, and there’s a USB power port to power the Pi.
Attaching the LCD to the case is a little nerve wracking, as like most tablet screens, it’s intended to be glued in. I used 3M permanent mounting tape (really not tape but adhesive on a backing roll.) It’s really difficult to cut with scissors (it sticks to everything) I made the mistake of putting it on the bezel and trying to cut it with an X-acto knife. I scratched the paint on the bezel, but I managed to fix it with a sharpie.
The better approach turned out to attach it to the opening, and cut along the opening.
After trimming I added the LCD, and the USB panel mount jack.
I had to drill a few holes because I hadn’t completely planned ahead, for a jack for the switch box (used a 1/4 phone jack and plug) power, and the 16 pixel LED array.
I had planned for it to swivel on the sides from two carriage bolts with wing nuts. This meant making a stand, and I didn’t want it to be just a couple of 2×4’s. Also I was running out of time so I took Justin’s suggestion and made a tripod mount for it. More holes…. And a mending plate from the hardware store. Fortunately I have a set of cheap taps from Harbor Freight, so it was pretty simple to drill the plate and tap it (1/4-20) to accept a tripod mount.
Getting it hooked up with the short cables is a little tricky, but there’s room to get your hands in there:
I used a proto-screw shield to make it easier to hook up the button and LED leads. As you can also see, there’s a small usb hub inside too.
I booted it up:
and then hacked Justin’s Wifit program to take a picture:
Justin then created a more kiosk-y gui, and I ironed out a few things with the Arduino code for AlaMode. The gui checks to see if an sd card is mounted, and when it is, it sends an enable command to the button and prints on the screen “Press Button when ready” The AlaMode then monitors for the button, and when pressed, sends the signal to take the picture and begins counting down on the LED strip. You can find the code in our github repository: https://github.com/wyolum/EPD
I tried also using the LED strip as a flash, and it worked but made sort of ghastly underlighting like a camp flashlight! So I took some cheap chinese led strip I had around (about $12 for 5 meters) and made a light panel:
And the finished product:
And on the badge:
I’m thinking of modifying the code to upload higher res pics to the Internet with an imprint, or printing them on a portable printer I picked up at a yard sale!
By the way, I left the Raspberry Pi’s wifi dongle attached, as it made it much easier to debug with SSH from my laptop. That said, I did also plug another hub into the one exposed port to use a keyboard and mouse (even though the touch screen does work!) If I had to do it over again, I might bring at least one more port out for other devices.
You’ll notice in the first picture, the Wyolum Logo across the top. Elizabeth Shaw cut that for me and delivered it the morning of the OHS, and it fit perfectly!