Lesson 13 · 60 minutes
Two Robots, One Room
Sharing space, control, and the airwaves
Today's goal
Run two robots at once without either one interfering with the other, and explain what could go wrong.
Ideas in this lesson
- Every robot has its own name, and names matter when there are twelve
- IR is a broadcast: one remote can hit several robots
- Bluetooth is a conversation: one phone, one robot
- Shared space needs rules, whether the drivers are robots or people
Sense → Think → Do
The same loop, twice, in one room — and now the environment includes another robot.
How the session runs
- Two robots, one IR remote. Press 5. Watch both react. Explain why.
- Now connect each robot to its own phone by name. Notice you must pick the right name.
- Give them opposite modes: one avoiding, one seeking. Watch them interact.
- Set them nose-to-nose in follow mode. What happens, and why is it unstable?
- Agree a room rule for the maze race: how do teams avoid running two robots into each other?
Try this
- Make two robots follow each other in a line without colliding.
- Can you make one robot deliberately confuse another's sonar? Should you?
- If twelve robots run at once, which of our systems would break first? Argue for one.
When it goes wrong
| What you see | What it means |
|---|---|
| Both robots react to one remote | IR is a broadcast with no addressing. That is a property of the medium, not a bug. |
| A phone connects to the wrong robot | Names come from the firmware. Check ROBOT_BLUETOOTH_NAME at the top of the kernel. |
Notes for the grown-up
The nose-to-nose follow demo is worth doing deliberately: two followers create a feedback loop with no damping, and they oscillate. It is a genuinely surprising and memorable result.