I’ve been building hardware and wanted to develop more skills in analog and digital electronics. Physics-123 is a popular course designed by Tom Hayes at Harvard who authored the companion text, Learning the Art of Electronics. Each week is a chapter in the book. Here is a bit of a journal from the two semesters.
The Fall 2020 analog courses’s problem sets helped build a practical intuition around analog circuits. We started with Thevenin’s theorem and worked our way through passive components, transistors, op-amps and some others. Here’s an index of my problem sets.
|Homework 02: RC Circuits||link|
|Homework 03: RC Circuits II||link|
|Homework 04: Diode Circuits||link|
|Homework 05: Transistors I||link|
|Homework 06: Transistors II||link|
|Homework 07: Op Amps I||link|
|Homework 08: Op Amps II||link|
|Homework 09: Nice Positive Feedback||link|
|Homework 10: Op-amps III||link|
|Homework 11: Design Manufacture||link|
I’ve been applying my learning in this course to sensors and actuators for a controlled environment mushroom grow chamber system I am prototyping. Mushrooms enjoy high humidity, low CO2, and moderate temperature. Over the course of digital and analog semesters, I prototyped each of these systems.
This is an air temperature control board I designed. It uses an LM34 IC which is this really cool IC that outputs .10mV per degree F. The board actuates a heating pad to warm and a fan to cool, according to some tunable thresholds and hysteresis.
For more about the project you can check out the manufacturing materials I designed for it.
I built a circuit to drive a piezoelectric disc for humidification, using a ‘555 to create a square wave at the piezo's resonance frequency. The oscillator drives a mosfet delivering higher voltage to the disc.
For the digital portion of the course I built a computer on a breadboard. Until this point I had only written my microcontroller code on an Arduino, and so it was a fun challenge to interact with the chip itself. We wrote some applications in Assembly language.
For our project I got this microcontroller to do some neat things like cactuators and collect data from a CO2 sensor. Here are some basic projects I did, collecting CO2 data from a TL6713 CO2 sensor and doing some various actuation with it. A challenge was really understanding the fundamentals of the I2C and UART serial communication protocols.