E-Sensor | Architectural Environment Measurement Device Specifications

Overview

E-Sensor is an open-source measurement device designed for the monitoring and analysis of architectural environments. Its USB connectivity enables seamless data acquisition across multiple platforms.

Multi-sensing: Integrated monitoring of temperature, humidity, wind speed, illuminance, and CO2 concentration in a single unit.
Cross-Platform: Compatible with PC (Windows/Mac) and mobile devices (iOS/Android) via USB Type-C.
Open Source: Hardware design files and software libraries are fully public.

Measurement Items

Item	Sensor	Measurement Range	Warm-up
Dry-bulb Temperature	SHT40	-40 – 125 °C	Approx. 5s
Relative Humidity	SHT40	0 – 100 %	Approx. 5s
Wind Speed	In-house	0.0 – 5.0 m/s	Approx. 5s
Illuminance	OPT3001	0.0 – 83865.6 lx	Instant
CO2 Concentration	STCC4	380 – 32000 ppm	Approx. 5s

Usage

Mobile (iOS / Android)

Install the dedicated application and connect the device via a USB Type-C cable.

iPhone / iPad (USB-C port): Connect directly with a USB-C to USB-C cable.
iPhone (Lightning port): Connect via an Apple "Lightning to USB Camera Adapter" or "Lightning to USB 3 Camera Adapter" together with a USB-A to USB-C cable.
Note: A standard Lightning charging cable cannot be used (iOS will not recognize the device as a USB peripheral).
Android (USB-C port): Connect directly with a USB-C to USB-C cable.

iOS App Android App

PC (Windows / Mac / Linux)

The device is recognized as a standard MIDI interface. Use the Python library for efficient data retrieval.

Python Library (GitHub)

Obtaining the Device

This is an open-source project. You can either build the hardware yourself using the design data or purchase a pre-assembled unit.

Purchase Finished Product (Amazon: Coming Soon)

Communication Protocol

Communication is performed using MIDI SysEx (System Exclusive Messages). Data payloads are transmitted in 4-bit nibbles (High nibble first, followed by Low nibble) according to MIDI specifications.

[F0] [7D] [Command ID] [Data 0 High] [Data 0 Low] ... [CRC High] [CRC Low] [F7]

Command List

Command ID	Dir.	Description	Data (Pre-nibble)
0x01	D → H	Send current sensor readings (Response to 0x02)	14 bytes (Sensor Data Structure)
0x02	H → D	Request current sensor readings	None
0x03	H → D	Start internal sensing process	None
0x04	H → D	Stop internal sensing process	None
0x05	H ↔ D	Transfer/Save calibration coefficient A	20 bytes (float[5]) + CRC(1 byte)
0x06	H → D	Request calibration coefficient A from device	None
0x07	H ↔ D	Transfer/Save calibration coefficient B	20 bytes (float[5]) + CRC(1 byte)
0x08	H → D	Request calibration coefficient B from device	None
0x09	D → H	Send device-specific serial hash value	4 bytes (uint32_t)
0x10	H → D	Request device-specific ID	None
0x11	D → H	Send firmware version information	3 bytes (Major, Minor, Rev)
0x12	H → D	Request firmware version	None
0x13	D → H	Notify CO2 calibration offset result	2 bytes (int16_t)
0x14	H → D	Execute forced CO2 calibration with reference	2 bytes (uint16_t) + CRC(1 byte)
0x15	H → D	Reset CO2 sensor to factory settings	None
0x16	D → H	Notify successful CO2 sensor reset	None
0x17	H → D	Request CO2 sensor initial conditioning	None
0x18	D → H	Notify that CO2 sensor conditioning has started	None
0x19	D → H	Notify that CO2 sensor conditioning is complete (takes approx. 22 s)	None

Sensor Data Structure (ID: 0x01)

Offset	Item	Unit	Type
0	Illuminance	Value × 10 Lux	uint32_t
4	Temperature	Value × 100 °C	int16_t
6	Humidity	Value × 100 %	uint16_t
8	Wind Speed	mm/s	uint16_t
10	Voltage	mV	uint16_t
12	CO2 Concentration	ppm	uint16_t
14	Flag	bit0: Illum, bit1: Temp/Hum/CO2, bit2: Vel/Volt	uint8_t