sensorclock

I'm a software engineer by trade and I was looking for a nice project to use Windows 10 IoT Core running on a Raspberry Pi 2 Model B. So I decided on an clock inspired by Steve Gardner's 6 Digit LED Clock project. Initially I only planned on the clock, but I ended up addeding a bunch of sensors that might be used for some "IoT" in the feature.

Everything is controlled thru I2C, except the RGB leds which use SPI, some GPIO's for the rotary encoder, interrupts from the sensors and control lines to turn off the +3V3 (to reset all I2C devices). Basically any MCU that has I2C, SPI and some GPIO's can be used.

The new Raspberry Pi 3 is pin compatible and runs even better

• Schematic
• Board Top
• Board Bottom
• Gerbers

things learned / improvements / mistakes

• U2 has an invalid I2C address
• [Workaround] Use ALLCALL to enable SUBADDR1 on all PCA9622's, then disable SUBADDR1 on the good addressed PCA9622's and use SUBADDR1 to address the wrong addressed U2
• The MCP3425 and DS3231 have the same I2C address #fail
• [Workaround] For now I cut the SDA/SCL traces to the DS3231
• The interconnect between te sensorclock and the Raspberrry Pi 2
• This is a custom cable which saved time in design process of the board (less complex routing), but in hindsight this was a mistake since the assembly of the cable is quite difficult and error prone.

features

• Windows 10 IoT Core controlled
• Six 7-segment 70mm (2.3") high displays
• Eight APA102C serial controlled RGB led's for ambient lighting or mood indication
• Temperature, humidity, barometric pressure, ambient light and air quality sensors
• Mechanical rotary encoder with switch for user input

components

• Raspberry Pi 2 Model B
• DS3231 [http://datasheets.maximintegrated.com/en/ds/DS3231.pdf] (address conflict)
• PEC16 [http://www.bourns.com/data/global/pdfs/pec16.pdf]
• APA102C [http://www.adafruit.com/datasheets/APA102.pdf]

clock

• PCA9622 [http://www.nxp.com/documents/data_sheet/PCA9622.pdf]
• SA23-11SRWA [http://www.kingbrightusa.com/images/catalog/spec/SA23-11SRWA.pdf]

sensors

• SparkFun Atmospheric Sensor Breakout - BME280 [https://www.sparkfun.com/products/13676]
• SparkFun Luminosity Sensor Breakout - TSL2561 [https://www.sparkfun.com/products/12055]
• MQ-135 air quality sensor, ADC and loadswitch
• MCP3425 [http://ww1.microchip.com/downloads/en/DeviceDoc/22072b.pdf]
• AP2280 [http://www.diodes.com/_files/datasheets/AP2280.pdf]

!!This is a work in progress, use at your own risk!!

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