Our first project has been successfully funded on Kickstarter BlueberryE: WiFi connected sensors (Arduino compatible)
As the title tries to explain we aka BlueberryE will make sensors available through a wifi connection in a Arduino compatible manner, the following give you a quick overview:
System consists out of 4 boards
the heart is a derivative from the Arduino Uno R3 SMD edition, we added level shifters (TI TXB0104 for SPI and the well known NXP circuit for I2C). The levelshifter can be individually switched on and off by jumper settings. In addition we put an 512kbit serial SRAM to enable local data storage. By setting jumpers the board can be used as a perfect Arduino Uno R3 clone (including form factor ect.).
Specs (current target)
- ATmega328 running at 5V programable using the Arduino IDE
- ATmega16U2 as USB to serial converter
- TI TXB0401 to optionally use SPI pins at 3.3V
- NXP Conversion Circuit to operate optionally I2C at 3.3V while I2C at A4, A5 works still at 5V
- Serial SRAM 512kBit at 3.3V SPI interface
- Same formfactor and pinout as Arduino Uno R3
next comes the wifi board. Here we could not overcome the temptation to stick with the cheap, yet powerful ESP8266EX-12 modules. The -12 module is among all the ESP8266 modules not the cheapest but it got FC certification and many pins of the ESP8266 chip (including e.g. ADC) are available.
The board will get the formfactor of an Arduino shield. Beside the wifi module it will get a SD card socket. We are planning a dual use of this board, on the one side as shield (on top of the Uno335 - not yet sure if it will work with a standard Arduino pinout) and on the other side as a standalone MCU board based on the capability of the ESP8266.
Please note: For safety reasons you must stay away at least 20cm from the board.
Specs (current target):
- Voltage converter to 3.3V LM3671 (buck converter 1A output)
- ESP8266-12 mit 3.3V Betriebsspannung
- 74LVC1T45 (Levelshifter RxTx Uno335) Interface: UART, SPI, I2C
- SD card for data storage
Environmental sensor board will have the Arduino shield footprint and we will make it to work both with the Uno335 and Uno8266 (shield and standalone mode). The plan is to add at least pressure, humidity and temperature sensors (use here the Bosch BME280 combi sensor) a UV sensor and IR sender/receiver.
Specs (current target)
- ATmega328 running at 3.3V programable using the Arduino IDE
- BME280 (pressure, temp, humidity) connected with I2C
- LTR303ALS01 (ambient light sensor) connected with I2C
- ML8511 (UV light sensor) analog out connect to ATmega328 ADC
- TSSP58038 für IR remote control (IR Receiver)
- VSMB10940 für IR remote control (IR Sender)
- Supply voltage 5V vom Arduino uno335
- Voltage converter to 3.3V mit LP2985
- 4 connectors (2x I2C, 1x analog, 1x digital) to Seeedstudio Grove, this way you can add more than 100 additional sensors and other useful things.
- CO2 sensor optional.
In our opinion the CO2 (carbon dioxide) sensor is the most important, but also the most expensive one. Reason is the chemical structure of the molecule that make common measurment principles like e. g. metal oxide (MOX) type gas sensors insensitive to CO2. One of the most reliable CO2 concentration measurement principles is NDIR (nondispersive infrared) but those sensors are expensive ~75USD and more. Anyhow we will add such a sensor as option to the EVS Uno.