Feb 2, 2025
and then I start to build the touch sensor.
Feb 5, 2026
Feb 12, 2026
Abbreviations
V : Volts
A : Amperes
W : Watts
mA : miliAmperes
VA : Volt Amperes
VAC : Volts AC
VDC : Volts DC
DC : Direct Current
AC : Alternating Current
Components
Conductors are materials through which electrical current moves freely.
Insulators are materials which prevent the flow of electricity.
Resistors resist, but do not totally block, the flow of electricity. They are used to control the flow of current. Current can move either way through a resistor, so it doesn’t matter which way they’re connected in a circuit. They are symbolized like this:
Capacitors store up electricity while current is flowing into them, then release the energy when the incoming current is removed. Sometimes they are polarized, meaning current can only flow through them in a specific direction, and sometimes they are not. If a capacitor is polarized, it will be marked as such on the diagram. Don’t wire a polarized capacitor backwards; it might explode.
Capacitors are symbolized like this:
Diodes permit the flow of electricity in one direction, and block it in the other direction. Because of this, they can only be placed in a circuit in one direction. They are symbolized like this:
Light-Emitting Diodes (LED’s) are special types of diodes which emit light when current flows through them. They are symbolized like this:
There are many other types of components which you’ll come across:
- switches control the flow of current through a junction in a circuit:
- transistors and relays are switching devices:
- thermistors change resistance in reaction to varying temperature;
- photoresistors change resistance in reaction to varying light;
- flex sensors change resistance in reaction to being bent or flexed;
- piezoelectric devices create a varying voltage in reaction to slight changes in pressure.
Sep 1, 2025
Sep 1, 2025
Sep 8, 2025
Sep 20, 2025
At first, I use soldering machine to connect wires with my speaker. Then, I use 3.3v for the power-in, but the number on multimeter was not my expectations. Somehow, I got the expect number, near 5V on multimeter, when I use the VIN pin for power-in.
Sep 20, 2025
Based on last week class, it’s necessary to make sure the original map range is same as the range from serial monitor.
On the first video, I test the output of FSR on serial monitor, then I got the data from the range of near 0-980. Then I applied this range to the map in my code, and the result went well. But here is one question: When I press slightly and keep hold this FSR, the servo would spin back and forth, WHY?
Still figuring out the creative part...
Sep 28, 2025
Sep 29, 2025
I want to build a hand that do the “🖖” & “🖐️” when people are paying attention to it. There’s a camera to detact people’s face.
After the day of my first prototype came out, I talked to Tom about my idea, and the feedback is: You can’t tell a person is paying attention if there’s an actual action. Means: If the person is looking at it or staring at it, you don’t know if they’re actually paying attentions on it.
Which makes me to reconsider my midterm idea.