Teensy Vibration Classifier (Embedded ML)

Built a real-time, vibration-based object classification system that detects an impact, extracts features, and classifies the object using a neural network running entirely on a Teensy 4.1 microcontroller.

The project demonstrates a full embedded ML pipeline—from physical sensing to on-device inference.

How it works (Nutshell)

A steel plate mounted on vibration-isolating feet rings after impact. An IMU captures the response, the firmware detects the event, extracts compact features, and performs real-time inference on the device.

Trained on eraser and screw impacts, the system achieved >99% accuracy under controlled conditions. The project demonstrates an end-to-end embedded ML pipeline: sensing, triggering, feature extraction, and on-device classification.

Skills: Embedded systems • Signal processing • Neural networks • Real-time firmware

To see a comprehensive report on this project, look here.
The full repository can be found here: https://github.com/FriChaFri/Arduino-Vibration-Object-Classifier

A Teensy 4.1 on a breadboard reads an IMU rigidly mounted to a thin steel plate. The plate is supported by TPU isolation feet underneath, allowing it to ring after impact. The eraser and screw used for classification are shown on the plate.

Example acceleration-magnitude waveform for a screw impact. The screw produces a sharper impulse with higher peak magnitude and faster decay compared to the eraser.

predicting.MOV

Real-time on-device classification. The trained neural network runs entirely on the microcontroller and classifies eraser and screw impacts in real time.

Alarm Clock

Goal

Build a sunrise-style alarm clock bright enough to wake me up by turning on the overhead lights.

Overview / Why I Built It

I wanted a light-based alarm but couldn’t use smart bulbs since my room lights were hard-wired LED strips.

The commercial sunrise alarms I bought weren’t bright enough, so I designed a servo-powered light-switch flipper mounted to a custom baseplate that replaces the wall-switch cover.

The Arduino-based system tracks time, lets me set alarms with buttons and a potentiometer, and triggers a servo to flip the switch at wake-up time.

Cad Model of baseplate design

Photo of Fully Mounted alarm clock.

Design Features

Custom CAD Baseplate: Designed and 3D-printed to mount directly over a standard light switch and hold the servo + electronics.
Bidirectional Motion: Mechanically capable of flipping the switch up or down depending on alarm mode.
User Interface: Buttons and a potentiometer to set current time and alarm time.
Power System: Battery + capacitors for servo current spikes. Optional wall connection for more reliable power.

LightSwitchAlarmVidShowcase

Video showing full operation

Challenges and What I Learned

Issue: Battery drain & voltage sag
- The servo drew more current than the small battery could supply; voltage dropped and reset the board.
- Solution/Lesson: Stepped the servo in small° increments, pausing to let capacitors recharge. Learned about power budgeting and decoupling.
Issue: Blocking code
- I used delay() for motion timing, which froze the entire program for ~30 s during servo movement.
- Solution/Lesson: Later learned about interrupts and non-blocking timing loops (using millis()) for concurrent operation.
Issue: Insufficient torque
- From the full “off” position, the servo couldn’t overcome the spring force of the light switch.
- Solution/Lesson: I “primed” the switch halfway before bedtime; in a future version I’d use a stronger servo or geared linkage.