Week 6 - Embedded Programming


Posted by Jordan Kennedy on October 24, 2017

This week our task was to program our circuit board. This circut board was either from Week 4 or a new board.

Because Week 4 was an abject failure, I had to make new board… which was also a failure. I need to revisit this and do again before Friday.

While I have taken two different electronics courses, the topic, on the whole, feels a lot like black magic to me. Largely, I imagine, because I am following a recipe on a breadboard that only really tests your ability to read electronic scematics. I’m hoping pratical design will take away some of the mystery. Also, milling boards makes you need to think much more about design as opposed to a breadboard with shared nodes.

Below is my design in Eagle.

Bad Design

Spoilers: It didn’t work.

Let’s discuss why and how I am going to fix this before Friday.

1) My first failed attempt from Week 4 was a result to too small leads. I over-compensated, and this week made them too thick and too close together. While I tried to manually etch was excess material (see below), it didn’t work and resulted in shorts.
To fix this I need to re-arrange my electronic components to give my leads enough room to be properly etched.

Over-Compensation Thank you to Brian for demonstrating the etching on my board.

2) My overall design is bad. Originally, I thought it was thin leads. This was only one problem. Thanks to our TA Brian Plancher, pointed out to me my connections out of my Tiny44 were not appropriately grounded. Furthermore, while not necessarily bad, my LED is in series with my button. While there is nothing technically wrong with this, it makes it so that I am not aware if my board is appropriately programmed. Therefore I need to tie it to another node.

However, when I plug it in, I get the red light giving a false sense of accomplishment.

Lit Board