Fuyang's Blog

On the way to achieve minimalism and essentialism

Month: September, 2015

Berkeley Electronic Interfaces Course – Robot Module 2 – Wheatstone Bridge


This second module on the EE40LX course is about using a Wheatstone bridge: any resistive sensor could be used in the bridge. The final robot we build in the course has two photocell “eyes.”

One key note on Wheatstone bridge is that, if one would like the swing of V_{out} to include both positive and negative voltages, one will have to make sure the choices of R1, R2, R4 to have a value between the lower and upper limit of R3, which is a photocell (VT90N1) in this case.


Photocell used here is EXCELITAS TECH VT90N1 LDR, 200KOHM, 80MW, VT900 Series.

Berkeley Electronic Interfaces Course – Robot Module 1 – Power supply


Recently I started to do an online course at edx. It is provided by UC Berkeley and the course is called Electronic Interfaces: Bridging the Digital and Physical Worlds. This course progressively builds on a bouncing robot. I found the teaching and the course content very good and interesting, thus I tried to purchase the parts needed online and now trying to build my own Robot.

And this, is the first module of the final Robot 🙂

In order to make the Robot brain, which is the LaunchPad M430G2, being able to work with a 9V battery, we need firstly to implement a voltage regulator on the breadboard. Basically speaking it takes in 9V and output 3.3V to match the voltage input M430G2.

LM1086 Voltage regulater

I try to use this blog to log the key information for each module so I can reference it later if I forget. I might later come back to add more info about why those capacitors are needed for this voltage regulator. As mentioned in the course the function of capacitors will be discussed in the later part of the course.