Like the robot Number 5 from Short Circut, the keyboard glove will need more than the handful of GPIO pins that the trinket provides. About 30 in total.
Shift Registers
Now, how do you get more pins on an Arduino? With a SN74HC165N of course!
What is a SN74HC165N you ask? It is a kind of shift register. It converts 8 parallel inputs into a series of pulses which can be read by the Trinket. Even better, you can chain these babies together to read even more inputs!
Now, I warned everyone that I am new to hardware design, and this is a great example. I picked out the parallel-to-serial converter without realizing that all those inputs would need pull-up resistors. Thirty-odd resistors will end up eating a lot more power than using a serial-to-parallel converter. Oh well, this is a learning experience, right?
Here's a picture of me trying out the SN74HC165N:
Reading the pins couldn't be easier! I'll add a snippet of code showing how soon.
I have to apologize for any slowness going forward. My laptop's video card died, and I've been reduced to using my tablet for pretty much everything. I guess we'll see how this goes!
More importantly, I've received a bunch of shipments from adafruit with the components for this build. Here, take a look:
On the top, we have the LiPoly backpack add-on for the trinket pro. On the left, we have the 3v trinket pro, middle is a 1200mAh lithium battery, and to the right is the HID bluetooth module. Finally, on the bottom, is the conductive fabric we'll be using to make the buttons.
I am still waiting on the gloves themselves, but for now let the soldering begin!
So, this is my second ever micro-controller project (this was my first), so don't expect too much!
I recently bought a tablet, and realized that it is very inconvenient to use without a keyboard. I've always had the idea of creating a keyboard glove, and the Trinket Everyday Carry Contest turned out to be the perfect motivation.
I'm aware of the Keyglove project, but I don't see a problem with a little competition! And besides, I want a super simple (read: cheap) glove keyboard I don't have to worry about destroying.