Week Three

It may only be Tuesday but a couple of major developments have occurred: we were assigned a group number of 5 (we still do not understand why we could not be group number q) and the parts we ordered last week started arriving. Thus far everything has proved acceptable except the prototyping board; the grid on the prototyping board we ordered does not interface with the switches as was implied in the online descriptions. While waiting for an RMA from Digi-Key it seems our options for a base are to either wire the switches directly and mount them to cardboard or to print/order a custom board. Due to time constraints of design and ordering, the first seems to be the better option as of now.

Moving forward, today's (Tuesday) meeting is mostly research of the secondary variety in the subjects of how exactly the the circuit will look and what the matrix for programming the keys is. Thus far the result of this has informed us that we will need diodes to prevent ghosting and masking in the keyboard behavior. Also, it is unclear as to whether LEDs can be directly hooked up to the switch matrix system, and testing of this circuit scheme has been deemed necessary.

Friday Status Report: We sorted the plastic key caps and made a keyboard layout. We then labeled each cap that will be used on the keyboard to save time in the future. We also set up a proof of concept circuit. It showed that placing the switch, LED, and diode in series would indeed light up the LED when the switch was pressed (see picture below). It has been decided that a small matrix of four to ten switches, LEDs, and diodes should be modeled at the next meeting to continue proof of concept/prototyping. Additionally, it was decided that we will design a keyboard cover out of cardboard/wood/acrylic to mount the keys on and then wire the keys directly. Six colors of 25ft 24 AWG stranded wires were bought in order to cleanly wire the board and increase the ability to trace wires when problems arise. Finally, a paintbrush will be bought over the weekend so that we can paint the keys at the next meeting.

Prototype Circuit: power to switch to LED to diode to ground