Tinycorder, a Multitool Device to Sense Environment, Test Electrical Signals and More.

Tinycorder is a small multipurpose device that seeks to pay tribute to the mythical tricorder from the science fiction series Star Trek. It includes several sensors, as well as a high-resolution, low-power screen that allows us to use it as an electronic badge.

It's small (75x85x10mm), light (70gr) and uses very low energy.

Main features:

-Two-piece PLA chassis that are joined together using 4 M3x10 screws.

-Includes hook to hang it from the neck or hand.

-XIAO ESP32C3 MCU from Seeed Studio.

-150mAh Lithium Ion battery.

-Power switch and 3 pushbutton for interface (Up, Down, Enter).

-Sharp Memory Display 400x240px from Adafruit. Very low consumption.

-AS7341 sensor for light measurement in 7 visible and NIR (near IR) bands.

-SCD40 sensor for measuring air quality and CO2.

-BMP280 sensor for measuring temperature, humidity and pressure.

-2 free pins accessible from the front to measure analog signals.

WORK IN PROGRESS

1. XIAO ESP32C3 MCU from Seeed Studio.
2. 150mAh Lithium Ion battery.
3. Power switch and 3 pushbutton for interface (Up, Down, Enter).
4. Sharp Memory Display 400x240px from Adafruit. Very low consumption.
5. AS7341 sensor for light measurement in 7 visible and NIR (near IR) bands.
6. SCD40 sensor for measuring air quality and CO2.
7. BMP280 sensor for measuring temperature, humidity and pressure.
8. 2 header pins.

Use this schematic to mount the device. Pay attention: some stuff isn't in Fritzing libraries and could be different. Read the notes.

1. 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.
2. 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.

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 to print the case in first place to align correctly with electronics and glue them later. In my case I didn't follow this way because I designed the pieces after glue components and take the measures, As you can see the design includes a hole for a wrist strap. And the same color than pla, I was lucky with that.

TO-DO:

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