Introductory · SPIKE Coding Project 5
Two knobs, three shapes — and your first drive to somewhere that isn't straight ahead.
Student PIN:
In Project 4 you worked hard to make your robot drive straight. Now you are going to ruin it on purpose — and pay close attention while you do.
Start a new project called Turns. Build one single move block — move (steering) for 24 in. — and keep the distance the same for every single run.
Then change only the steering dial. Set it to each value below, run it, and describe the path the robot took.
⚠ Floor, Not Table
These runs go in circles and curves. Do this on an open floor with nothing in the way — not on a table, not on the field.
| Steering value | What path did the robot take? |
|---|---|
| 0 | |
| 10 | |
| 25 | |
| 40 | |
| 50 | |
| 65 | |
| 85 | |
| 100 |
Fill in the blanks from your own runs:
| When the steering number is… | The robot… |
|---|---|
| close to 0 | |
| getting bigger | |
| exactly 50 | |
| all the way at 100 |
In Project 3 you predicted what the robot would do when both motors got the same arrow. Somewhere in this table, exactly that happened to the wheels. Which steering value was it — and were you right?
You only have two things to adjust, and they do completely different jobs.
| Code / part | What it means |
|---|---|
| the steering dial | Sets the shape of the path. One number decides whether the robot goes straight, curves gently, curves hard, or spins on the spot. |
| the amount | Sets how far along that path the robot travels — inches or degrees. It does not change the shape at all, only how much of it you get. |
The Two Rules You Just Discovered
The closer the steering is to 0, the straighter the robot goes.
The bigger the number, the sharper the curve.
Everything else in this project is those two sentences applied on purpose.
| Turn | What it means | Steering |
|---|---|---|
| Both wheels go the same direction at different speeds. The robot sweeps a wide arc, like a car going around a bend. Sharpness comes from how big the steering number is. | steering / 1 to 49 | |
| One wheel drives, the other sits still. The robot swings around the stopped wheel — like ring around the rosie. More speed means a faster swing, not a tighter one. | steering / exactly 50 | |
| The wheels go opposite directions. The robot spins in place without moving forward or backward at all. Also called a pivot or spin turn. This is what you use for precise angles. | steering / all the way: 100 |
Which One Should You Use?
Zero radius when you need to point a different direction without giving up your position — the usual choice on a crowded field.
Radius when you want to travel and turn at the same time, like driving around an obstacle.
One-wheel when you want to swing around something you are already next to.
Friction Matters More Than You Think
Two moving wheels fight friction better than one moving wheel does. A asks a stopped wheel to skid sideways, so it is the least repeatable of the three. If a turn will not come out the same twice, try the same turn as zero radius instead.
New Number Alert: Degrees on a Move Block
When you set a move block’s unit to degrees, it counts how far the wheels turn — not how far the robot turns. Spin at steering 100 for 90 degrees and the robot turns far less than a right angle, because each wheel only rolled a quarter of the way around.
Nobody can work out the right number from their chair. You find your robot’s 90° the same way you found your distances: test, nudge, test again.
One more dial fact: steering works on both sides. Positive numbers turn right, negative numbers turn left — a spin to the left is steering −100.
Mission 12
Two spilled cubes form a scoring stack — one spilled cube is another spilled cube. Both cubes must originate from the spilled cube area. Edge-to-face or corner-to-face contact does not satisfy this definition for Mission 12.
The scoring stack remains intact and the lower cube of the stack is touching the black line.
New project called Circles. Put a chair in the middle of an open floor.
Write a program that drives your robot in one big circle all the way around the chair, without it. Use one single move block — no stopping and restarting.
| Steering value | Distance (in.) |
|---|---|
Swap the chair for something small — a tissue box works. Circle that instead, same rule: one set of commands.
| Steering value | Distance (in.) |
|---|---|
Compare your two sets of numbers. What did you change to make the circle smaller?
Run each one and record what the robot actually does.
| Turn type | My steering | What it did |
|---|---|---|
| Radius | ||
| One-wheel | ||
| Zero radius |
Which of the three moved the robot the least distance across the floor? Why does that matter on a crowded field?
New project called Right Angle. Use a zero radius turn — steering 100 — and find the degrees value that gives you a true 90° robot turn.
Keep the steering at 100 the whole time. Change only the degrees.
| Try | Degrees | Too far, not far enough, or right? |
|---|---|---|
| 1 | ||
| 2 | ||
| 3 | ||
| 4 | ||
| 5 |
Test One Step at a Time
Get the turn right on its own before you attach it to anything else. one command is easy. a whole run to find out which command was wrong is not.
Here is the honest test of a 90° turn: do it four times and see if you end up where you started, facing the way you started.
Drive forward, turn 90°. Repeat four times total.
If your robot did not close the square, was each turn too much or too little? How could you tell?
A small error in one turn becomes a big error after four. This is why turning by wheel-count alone is hard — and why Project 11 hands you a sensor that can feel the robot itself turning.
Onto the field. New project called Approach 12.
Start in your starting box, exactly the way you decided in Project 4. Drive out, turn, and stop next to the spilled cube area — close enough and square enough that a claw could pick a cube up.
Write your plan as first:
| Code / part | What it means |
|---|---|
| 1. Drive forward | Out of the starting box. |
| 2. Turn | Toward the spilled cubes. |
| 3. Drive up to them | Close enough to work from. |
| 4. Stop | Square to the cubes. |
| Move | Steering | Amount | Unit (in. or deg) |
|---|---|---|---|
| Forward | |||
| Turn | |||
| Approach |
Same rule as Project 4. One good approach is luck.
| Run | Did it arrive in a position a claw could work from? |
|---|---|
| 1 | |
| 2 | |
| 3 | |
| 4 | |
| 5 |
No points yet — Mission 12 does not score until something gets stacked. What you have built is the half of the mission that has to work before the other half matters.
Every project from here uses these. Write them down properly.
| Setting | Value |
|---|---|
| — steering value | |
| Degrees for a 90° turn | |
| Degrees for a 180° turn | |
| Degrees for a 45° turn |
You worked out 90° by testing. Did doubling it give you a good 180°? Did halving it give you a good 45°?
| The robot needs to… | Which turn type? |
|---|---|
| Face the other way without leaving its spot | |
| Curve around a cone while still moving down the field | |
| Swing its front end around a cube it is already beside | |
| Make a small heading correction while driving straight |
Your square test almost certainly did not close perfectly. Where did the error come from — was the robot doing the wrong thing, or was your program asking for something it cannot deliver?
A teammate’s robot turns 90° perfectly on the carpet but s on the field mat. Nothing in the program changed. What happened?
You now have a robot that gets to the right place and points the right way. What is the next thing it needs before Mission 12 can actually score?
In Project 6 — Bulldoze Run, you put driving and turning together to score four missions at once — and you do it all without a claw, by pushing.
Download saves a local copy of your answers. It does not turn in your work automatically; give the downloaded file to your teacher.
KIPR · Botball Explorer — Introductory Projects · © KISS Institute for Practical Robotics 1997–2026