Oct 5, 2025
DC means Direct Current: electricity that flows in one constant direction.
What’s the difference between DC motors, RC servomotors, and stepper motors?
-Key differences in practice:
- DC motors: simplest; you vary voltage to change speed and reverse polarity to change direction. Need a driver (H‑bridge) and protection diodes for back voltage.
- RC Servomotors: you command a target angle with pulsewidth; they include gearing and position feedback, so they “go to” and “hold” positions without external sensors.
- Stepper Motor: you move in exact steps by driving coil sequences; excellent for repeatable positioning, usually open‑loop (no internal feedback), and require dedicated stepper drivers.
Oct 5. 2025
My process of soldering the motor driver went very well at first, but I don’t know why the angle of the pins changes when I take the driver off the breadboard. I tried to melt the solder and imagined gravity could do the work, but unfortunately I failed. I thought I would probably need to buy a new one. Then I thought maybe the solder sucker could work. Ceren doubted me at first, but I insisted. I added more solder on the top and used the sucker to extract from the bottom—and it worked!
(I’ve been there before)
Just like riding a bike
Oct 5, 2025
The author challenges the myth of “natural” or “intuitive” interfaces using the metaphor of learning to ride a bike: what feels effortless is actually the result of prior practice. Interfaces exist to abstract complex systems, but they still demand users learn what can be manipulated and how actions map to outcomes. Even celebrated gestures like Apple’s pinch‑to‑zoom felt “intuitive” largely because launch ads acted as micro‑tutorials; many first‑time users still struggled.
Labeling interfaces as “natural” can erode empathy, blaming users when they simply haven’t learned yet. A better lens is ease‑of‑learning on a sliding scale, shaped by the user’s past experience and the interface’s reliance on familiar metaphors (cut & paste, file folders, stars). In short: “intuitive” means it draws on already learned behavior; “unintuitive” asks for new skills or mappings. Designers should embrace the teaching responsibility—build discoverability, clear affordances, feedback, and safe trial—because the learning curve can be flattened, never erased.
Oct 6, 2025
Oct 6, 2025
Built the circuit:
I was not familiar with LM358, but I still tried to understant it.
Coding:
I copied the code in the doc but two of the libraries (NewPing, NewTone) cannot being used by Nano. So I asked ChatGPT to change the library to one that works for the Nano. I uploaded successfully and got the number from my ultrasonic sensor in Serial Monitor. But the problem is I couldn’t hear anything from my speaker. I tried to troubleshoot by changing a speaker and adding a transistor to make the sound louder?, but I failed at both :(
What is a theremin?
A theremin is an electronic musical instrument controlled without physical contact by the thereminist (performer). It was patented by Leon Theremin in 1928. The instrument's controlling section usually consists of two metal antennas that sense the relative position of the thereminist's hands and control oscillators for frequency with one hand, and amplitude (volume) with the other.
click to play the video.
it finally worked!!!
credit to Gabriel, and also Justin & Arjun who told me to try this :)