Tinycorder, a multitool device to sense environment

A small multipurpose device with sensors

Tinycorder is a small multipurpose device inspired by the legendary tricorder from the science fiction series Star Trek. It includes several sensors and a high-resolution, low-power display that allows it to be used as an electronic badge.

It's compact (75x85x10mm), lightweight (70g), and consumes low energy.

Main features:

• Two-piece PLA chassis assembled with 4 M3x10 screws.
• Includes a hook to hang it from the neck or wrist.
• MCU: XIAO ESP32C3 from Seeed Studio.
• 150mAh lithium-ion battery.
• Power switch and 3 pushbuttons for interface (Up, Down, Enter).
• Sharp Memory Display (400x240px) from Adafruit. Very low power consumption.
• AS7341 sensor for light measurement in 7 visible and near-IR bands.
• SCD40 sensor for air quality and CO₂ measurement.
• BMP280 sensor for temperature, humidity, and pressure measurement.
• 2 free pins accessible in the front to measure analog signals.

Some functions already implemented:

Electronic badge with functional QR code.

(To make your own badge read the notes in src code)

Spectrometer with 7 bands + NIR (numeric values and bar chart)

How to make one:

• Join the perfboard (70x30mm) and display with glue or soldering.
• Wire all the sensors and display following the schematic. The display uses 3 pins for SPI and sensors 2 pins for I2C. 3 pins for pushbuttons (up, down, enter). 2 pins are connected in the front to header pins, they are analog pins.
• Solder the XIAO in the topside but take care of align the perfboard holes. XIAO ESP32C3 has two pads in the bottom to connect the battery and you must solder them in the bottom, it's a little tricky.

• Glue the sensors in the bottom side, also the wiring, see the picture:

• In the front, glue the battery:

Join the top-bottom (PLA) case with nuts & bolts. I've used M3x10. I've need some iterations to fit all the componentes, this is also tricky. If you made one maybe is better print the case in first place to align correctly with electronics and glue them later. In my case I follow this way because I design the pieces after glue components and take the measures, As you can see the desgin includes a hole for a wrist strap. And the same color than pla, I was lucky with that.

TO-DO:

• Refine the code, main menu, badge and spectrometer are ok, the rest are in construction.
• Monitor battery voltage and display it via an indicator.
• Include a buzzer.
• Add pending functions like tester/oscilloscope.
• New features as they come to mind.