Parts list first, because this one is short: a UNIHIKER K10, a DFRobot 8×8 Matrix ToF distance sensor, a Gravity HX711 weight sensor kit, and a Gravity I2C hub to tie them together. That is the whole shopping list behind Jaychouu’s parcel measuring station, and it is a good template for any sensor-fusion build.
What the build does
Put a box on the platform and the system reports weight, height, length, and width, then pushes the numbers to a web page that can look up shipping rates. Think of a bathroom scale that also knows the size of what is standing on it. For anyone who ships a few parcels a week, that replaces a hunt for the tape measure and a fraction-to-decimal conversion.
How the sensors split the work
The HX711 load cell kit is the scale. The 8×8 ToF matrix returns 64 distance readings per frame, so it can see the shape of the box from above instead of a single point. Height is subtraction: distance to the empty platform minus distance to the box top. Length and width take a bit of trigonometry, using the measured distance and the angle to each detected edge.
The K10 acts as controller and screen. It reads the sensors through the I2C hub, so SDA and SCL are shared and you avoid a nest of jumper wires. It also draws a small grid showing which cells of the ToF matrix are covering the box. In the demo, the K10 sends readings over serial to a PC, where the custom page shows them.
Build it yourself
- Calibrate the HX711 with a known weight, such as a 500 g reference, before trusting any reading.
- Mount the ToF matrix at a fixed height, since the trigonometry assumes the platform distance never changes.
- No shipping API? Type the values into your courier’s form, or log them to a CSV for a school canteen or club inventory.
- If a reading jitters, average 10 samples before you display it.
Read the original coverage on Hackster.io, then check the UNIHIKER K10 and DFRobot Gravity sensors at circuit.rocks for a classroom measurement project.
Frequently Asked Questions
How does the system measure a package’s size?
An 8×8 time-of-flight matrix gives 64 distance readings. Height comes from platform distance minus box-top distance, and length and width come from trigonometry using edge angles.
What parts and skills does this build need?
A UNIHIKER K10, a DFRobot 8×8 Matrix ToF sensor, a Gravity HX711 weight kit, and an I2C hub. You need basic I2C wiring, serial output, and a simple web page.
What will I learn if I build this?
You learn I2C sensor wiring, load cell calibration with the HX711, reading a multi-zone ToF sensor, and basic trigonometry for geometry from distance data.
