The goal of this project was to make a Sous Vide machine. This Sous Vide is temperature-controlled cooking method. It requires to place ingredients in a sealed environment while being cooked under water. The food is cooked by sealing it in a vacuum sealed bag then placing that bag in a water bath. The water bath is then heated to a specific temperature, typically the temperature at which the food becomes safe to eat, especially important when meat is begin cooked. The typical temperature range is 60-90 deg C depending on the type of food. It is then left in the water bath for a long period of time until the food reaches the temperature of the water bath.
The project wasn’t successful because we weren’t able to communicate with the temperature sensor. Unfortunately we couldn’t find a library for the temperature sensor to communicate with the A3BU. (Instructor note to future teams searching for a project idea: consider adding 1-Wire code to the A3BU. You will learn a ton about timers) Other than that the project went well and we used a manual temperature sensor to make all the necessary readings and finish the project.
This is our schematic for all of our hardware for the final project. Very simple, I know. That is on purpose. We chose peripherals that required very little hardware. The 4×3 Keypad was almost plug and play, with only a little code required to receive and use user inputs as a passcode.
The piezoelectric speaker was the same deal, with us piping out a particular frequency which corresponded to a musical mote. The notes weren’t perfect, in part because of the speaker quality and also because the duty cycle was not at 100%. Perhaps if we up the duty cycle to very close to 100% we would get something closer, but as is the notes fall flat. Originally an 8 ohm 1 W speaker in series with a resistor was going to be used but the PE speaker is much smaller and required mo extra hardware, making it a simple design choice when going for minimalist designs.
The relay powered and controlled by the board and opening/closing the circuit for the electromagnet and battery pack is the most complicated hardware in our project, and took a little bit of troubleshooting in the code to get it to work. The battery pack is a set of four 1.5V AA Batteries and provided a nice ~3.3A of current to work with. It also stayed steady enough to last a while, plenty of time to do a demo several times over.
Overall, because of our design choices we kept everything as sleek as possible to drive the EM, turn it on and off with a keypad and implement success/failure tones.