Projects / Ultrasonic Rangefinder Lab
Ultrasonic Rangefinder Lab
Build an HC-SR04 ultrasonic distance instrument on a laser-cut 3mm birch plywood stand—parking-sensor style alerts and a live distance display. Measure time-of-flight and convert to distance with an explicit speed of sound.
$7 Sensing
Digital guide + cut files + BOM + code · Parts sourced separately · Ages 8–14 with adult help
SensorHC-SR04
Structure3mm birch stand
DisplaySerial (OLED optional, USE_OLED 1)
ControllerArduino
Build time2–4 hours
Skill levelBeginner–intermediate
Pack contents
- Upright, base, sensor yoke SVGs
- Lab exercises: ruler compare, angle sweep, soft target
- First-principles: ToF, beam, temperature effects
- Alert-zone firmware
- Verified BOM (~$18–73 hardware)
Typical hardware cost
Default structure is laser-cut birch plywood with real fasteners and hobby electronics you can source—honest BOM, not mystery modules.
- ~$18–73 in typical parts (makerspace cut toward the low end; mail-order toward the high end)
- Digital pack price ≠ hardware
The $7 pack is the digital guide + cut files + BOM + lessons + code, plus printable Builder's Corner build journal pages. Hardware is sourced separately — see Where to get kit materials. Buy with Stripe is live below.
Questions? Email us at lance.haney@gmail.com.
Pricing
- Home / Personal license $7
- Classroom license $29 — 1 teacher, up to 30 studentsOne $29 Classroom license covers one group of up to 30 students. Each additional group needs another license.
- Build materials available at cost + 10% — email for a quote
Learning outcomes
- Trigger HC-SR04 and measure echo pulse width
- Convert ToF to distance with explicit speed of sound
- Define near / mid / far alert zones
- Explain soft-surface and angle failure modes