Session 2
Ohm's Law and a Traffic Light
At Skill Hub we met Ohm's law, built a traffic light out of three LEDs, and found out that rules in electronics aren't there to be memorised. They're there because things burn out.
- Date
- Place
- Skill Hub
- Topic
- Arduino
Ohm's law usually shows up as a formula to learn for a test. V equals I times R. Write it down, move on.
On a breadboard it feels different. Skip the resistor and the LED doesn't get a lower mark, it just gets too much current. The rule isn't an opinion. It's what keeps the part alive.
That changed how the rest of the session felt. Current, voltage and resistance stopped being three words and became three things you could get wrong with your own hands.
Once the LED and resistor were sitting happily together, we gave them a job. First a blink. Then three LEDs, red, yellow and green, timed like the traffic light outside. Then patterns, then a buzzer that could play tones.
The traffic light is my favourite of those. It's something everyone has waited at a hundred times without thinking about it. Building one makes you notice that somebody decided how long yellow should last. Someone wrote that down. The world is full of small decisions like that, and most of them are invisible until you try to make one yourself.
A lot of the session was debugging. A wire one row off. A leg in the wrong hole. Nobody enjoys that part at first, but it's where you stop following instructions and start reading the circuit for yourself.
By the end, every student had uploaded code they'd written and changed. Not copied. Changed. That's the difference I care about.