Progress

This week we realized that we needed to rethink a lot of our circuit and embedded design after our design presentation. Our tiles were drawing a lot of current, which would make our product not child-safe. Since child safety is one of our top technical requirements, Eric redesigned our circuit so that each tile is powered by its own set of batteries. These tiles would start out in sleep mode, and would wake up once it detects a side trying to communicate with it (via interrupts). We decided that tiles also would send messages as brief chirps to be caught by interrupts rather than leaving the sender’s IR pin on for an entire clock cycle (and having the receiver poll for it). Eric and I tested out the sleep-mode IR interrupt idea in the Atmega328p environment, and we found that the reaction time when an interrupt is triggered is very fast and that a very small amount of current is used while the Atmega328p is in sleep mode. More details of our findings can be found in Eric’s blog post. Since we are switching our embedded protocol, I’m once again going to have to refactor my Python simulator.

Another thing I got done this week was prototyping the design of the tile enclosures in CAD. The assembly can be seen below:

Schedule

This week’s changes are hopefully the last major redesign of our circuit and embedded system, because we’re already pretty behind schedule. We are also going to make use of the slack time we dedicated towards spring break to catch up.

Goals for next week

• Refactor and complete Python simulation code
• Continue familiarizing myself with the Atmega328p environment
• Refine CAD drawing and begin considering tile material