Live dream
A simulated Swing Kid, running the brain as it is right now.
Hold ← or → to swing the legs back or forward. Try to pump it up yourself.
Practice worlds
12 of the 64 swings it practices on at once, each built a little differently, running the brain with its exploration noise on. The pink ticks show the height each one is asked for.
Inside the brain
Lines are connections (blue negative, red positive, thicker is stronger). Circles light up as neurons fire for the live dream. The output is where the legs go.
- Practice
- 0 min in 0 s of real time
- Practice runs
- 0 0 learning steps
- Average miss
- – swing height vs. target, on 6 test swings
- Curiosity
- – how much it still experiments
At 100% every practice run gets a different string length, box weight, feet, servo strength, drag and gyro drift. Slide it to 0 and the brain only ever practices on one perfect swing.
Learning curve
How far the swing's height is from the height asked for, averaged over 6 test swings with the brain's experimenting switched off. Lower is better. The dashed line is the textbook pumping rule on the same 6 swings.
What the brain does
legs backlegs forward
Every point is a moment in a swing: how far out it is (left–right) and how fast it's moving (up–down). A steady swing traces a circle, and a bigger circle is a higher swing; the dashed circle is the height asked for. Color is where the brain puts its legs. The dark line is the live dream.
Final exam
Worlds passed–run the exam
Holds within–
Gets going in–
Stops in–
| Brain | Textbook rule |
|---|
brain's swing heighttextbook rule'sheight asked for✕ = a world the brain failed
Where the brain lives
settings and calibrationthe brainfree
Each square is one byte. The trained network's 401 numbers are squeezed to one byte each (one scale per layer), plus a header and a checksum the robot verifies before it trusts a new brain. The exam grades this squeezed copy, exactly as the Arduino will run it.
This copy of the Gym can't reach USB
It can dream, run exams and drive a virtual Swing Kid, but this browser or this page can't talk to a USB device. In Chrome or Edge, open michaellomuscio.github.io/swing-kid/gym, or double-click Swing Kid Gym.command in the swing-kid folder to run it from your Mac.
1 · Connect
Plug the Arduino into your Mac with the USB cable, then pick its port (usually called usbmodem or usbserial).
2 · Firmware
The program that runs on the Arduino. Install it once; after that, brains travel over the same cable without reinstalling anything.
3 · Check the parts
Gyro–GY-521 board in the box
Remote–press any button, aimed at the box
Before the legs are on, the servo horn should turn when you press the leg buttons. If the face is sideways or mirrored, press Rotate face until it looks right.
4 · Center the servo
Do this before you zip-tie the legs on. Swing Kid holds its servo exactly in the middle; push the horn onto the shaft so the stick hangs straight down.
5 · Calibrate
Hang it still (steady the box with a hand, then let go), and start. Swing Kid holds still, kicks a few times, swings freely, then pumps itself up and brakes. About 40 seconds.
- Hanging still: the gyro's resting drift
- Kicking: which way it swings
- Swinging freely: its own rhythm
- Pumping with the textbook rule
- Braking with the textbook rule
| Real swing | Fitted dream |
|---|
6 · Brain
On the robot now: –
Reality
What Swing Kid feels, live over USB.
Hold ← or → (or drag Legs) to kick. Can you pump it as well as the brain?
Swing height, last 20 seconds
Dream vs reality
A 20-second test in Brain mode: up to 25°, then stop. Then the dream gets the exact same leg moves the robot made, and you can see how far apart they drift.