Perfboard

Week 4 was shortened because of the long holiday weekend for the 4th of July, but it was still productive! This week, we finally, finally got the complete circuit working!! So, I transferred it all to a perfboard, which is a more permanent, soldered-on circuit that winds up being much smaller and eliminates the issue of wires accidentally being unplugged. This process was long, because first we redid a more organized version of the breadboard where all of the wires were shortened so the connections could easily be seen. Then I used the software Fritzing to plan out the perfboard wiring before I actually started to solder all of the wires to an Arduino-specific perfboard called an Arduino shield, which fits neatly on top of the Arduino Uno and shares the same footprint:

All of the wires that stick out of this perfboard go to specific components, such as the screen, heating pad, thermometer, and piezo (alarm). This will make our final product much easier to work with and fit into a smaller box!

 

We did encounter one issue when we tried to assemble everything–– we fried yet another screen! At first this seemed like a major setback, but then I realized that on this OLED, the screen had fried, but on the previous one, the circuit controlling the screen had fried. So I tried something:

I ripped the screens off of their PCBs, swapped them, and plugged in the ribbon connection, and it actually, remarkably, worked! Because the connection is still looser than it should be, we did order another screen to use in the final design, but for testing, this is sufficient.

New Box

Since the circuit was going to be so much smaller, we also implemented our new box design! Instead of two side-by-side chambers, in this box the electronics chamber is the same size as the heating chamber and positioned directly above it. Here’s what it looks like fully assembled, including the screen and buttons on top:

We’re currently conducting a comparative incubation test with our device and a lab incubator which was lent to us by a biology professor. If all goes well, our device is in it’s final stage and ready for presentations next week!