Build load cell pedals lesson plan
Sim racing pedals on a Pro Micro in three short lessons: a load cell brake on an HX711, a hall throttle and a pot clutch, and the curve that makes it feel right.
Objectives and materials
By the end, students can
- A brake that weighs your push, and two pedals that measure travel.
- A curve, a deadzone and a report that does not chatter.
Materials for the whole unit
- Full-size breadboard
- Hall sensor, 49E linear
- Load cell with HX711
- Potentiometer
- SparkFun Pro Micro
Every part is already on the simulator’s bench, so there is nothing to buy or hand out. The counts are the most any one lesson uses, if you build it on real breadboards too.
Force and position
A brake that weighs your push, and two pedals that measure travel.
| Lesson | Time | What students do |
|---|---|---|
| A brake that measures forceA beam load cell on an HX711: why a brake should read how hard you push rather than how far, taring at start-up, and counts per kilogram. | 20 min |
|
| Throttle and clutchA hall sensor throttle and a pot clutch: calibrating two readings into a full 0 to 1023, with a little dead travel at each end. | 20 min |
|
Materials
- Full-size breadboard
- Hall sensor, 49E linear
- Load cell with HX711
- Potentiometer
- SparkFun Pro Micro
Check for understanding
Each student finishes "Throttle and clutch" on their own, without opening the hints. The simulator checks 4 of its 4 steps as they go.
Then ask each one to explain, in a sentence or two, the last thing it asked of them: "Dead travel at each end".
The feel
A curve, a deadzone and a report that does not chatter.
| Lesson | Time | What students do |
|---|---|---|
| The brake curve and the reportShape the brake with a curve and a deadzone, keep load cell noise out of the report, and know what changes on a real Pro Micro. | 20 min |
|
Materials
- Full-size breadboard
- Hall sensor, 49E linear
- Load cell with HX711
- Potentiometer
- SparkFun Pro Micro
Check for understanding
Each student finishes "The brake curve and the report" on their own, without opening the hints. The simulator checks 4 of its 4 steps as they go.
Then ask each one to explain, in a sentence or two, the last thing it asked of them: "On a real Pro Micro".
Teach this unit as a class
Start a class from this course and its 3 lessons are assigned in one go, in order. Students join with a six-character code or printed login cards, and each one’s work comes back to you.
The class tools are free for 30 days for one class of up to 20 students, with no card. The lessons themselves are free either way.