public:raspberry_pi_weather_station_board
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public:raspberry_pi_weather_station_board [2016/12/31 14:01] – [DN7C3CA006] fangfufu | public:raspberry_pi_weather_station_board [2019/01/19 03:56] (current) – fangfufu | ||
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+ | ====== Raspberry Pi Weather Station Board ====== | ||
+ | |||
+ | ===== Private Sections ===== | ||
+ | [[private: | ||
+ | |||
+ | ===== Project Updates ===== | ||
+ | I bought an Arduino, another I2C logic level shifter. Now the goal has been moved to running BME280 and the PM2.5 sensor off an Arduino. The constraint is still the 4-wire connection to the outdoor environment. | ||
+ | |||
+ | ===== Bill of Material ===== | ||
+ | This is the current estimate of the minimum cost for constructing the whole thing. It doesn' | ||
+ | |||
+ | ^Name ^Cost (£) | | ||
+ | | Raspberry Pi Zero | 4 | | ||
+ | | DN7C3CA006 | 14.04 | | ||
+ | | BME280 | 13.28 | | ||
+ | | ADS1115 | 9.96 | | ||
+ | ^Current BOM cost (£) |~~=sum(range(1, | ||
+ | ===== Specification ===== | ||
+ | This weather station board should be able to performed the following functions: | ||
+ | - Sense temperature | ||
+ | - Sense humidity | ||
+ | - Sense air pressure | ||
+ | - Sense PM 2.5 [(Fine particle (PM2.5) Designations > http:// | ||
+ | |||
+ | ===== Choosing the component ===== | ||
+ | ==== Raspberry Pi ==== | ||
+ | |||
+ | I have decided that this extension board should comply with the RPi GPIO connector standard. This is because RPi 0 is the cheapest development board you can get in the market [(Raspberry Pi Foundation - Raspberry Pi Zero > https:// | ||
+ | |||
+ | For prototyping, | ||
+ | |||
+ | ==== Temperature Sensors ==== | ||
+ | I have decided to use I2C temperature sensors only, below is a list of possibilities: | ||
+ | |||
+ | ^Name | ||
+ | | HDC1008 |7 | 0.2(typ)/ | ||
+ | | MCP9808 | 9.3 | 0.25(typ)/ | ||
+ | | HTU21D-F | 13.50 | 0.3(typ)/ | ||
+ | | BME280 | 18.50 | 1 | https:// | ||
+ | | HIH6130 | 24 | 1 | https:// | ||
+ | | MPL115A2 | 10 | Unknown | https:// | ||
+ | | MPL3115A2 | £9 | 1 @ 25 $^\circ$C| https:// | ||
+ | | BMP180 | 10 | 2 | http:// | ||
+ | |||
+ | I have listed them in the order of desirability. The top two options are both okay. | ||
+ | |||
+ | ==== Pressure Sensors ==== | ||
+ | I have no idea how atmospheric pressure is related to the weather. It is a fun thing to measure anyway. I have decided to only use I2C sensors, for simplicity. Please note that I chose to use relative accuracy in the table. Different manufacturers use different ways to measure relative accuracy. For more details, refer to their individual datasheet. | ||
+ | |||
+ | Below is a list of possible pressure sensors: | ||
+ | ^Name | ||
+ | | BME280 | 18.50 | 0.12 | https:// | ||
+ | | BMP180 | 9 | 0.12 | https:// | ||
+ | | BMP280 | 9.50 | 0.12 | https:// | ||
+ | | MPL115A1 | 10 | 10 | https:// | ||
+ | | MPL3115A2 | 9 | 1 | https:// | ||
+ | | T5403 | 11 | 0.15 | https:// | ||
+ | |||
+ | ==== Humidity Sensors ==== | ||
+ | The local temperature is required for calculating relative humidity. This means that humidity sensors come with temperature sensor. | ||
+ | |||
+ | ^Name ^Price (£) ^Relative humidity accuracy (%) ^URL ^Other notes | | ||
+ | | HTU21D-F | 13.50 | 2 |https:// | ||
+ | | BME280 | 18.50 | 3 | https:// | ||
+ | | HDC1008 | 7.00 | 4 | http:// | ||
+ | | HIH6130 | 24 | 4 | https:// | ||
+ | |||
+ | ==== The PM2.5 Sensor and the ADC ==== | ||
+ | Well, there is only one PM2.5 sensor exist on the market [(Sharp - PM2.5 Sensor Module > http:// | ||
+ | |||
+ | The PM2.5 sensor outputs analogue voltage, so I need an ADC. I have decided to pick one from Adafruit - since every other breakout board I bought are from Adafruit. This ensures compatibility. I have decided to go for the 16-bit 4-channel ADC [(https:// | ||
+ | |||
+ | ==== Final Decision ==== | ||
+ | |||
+ | I have decided to buy the following sensors: | ||
+ | |||
+ | ^Name ^Price, excluding VAT / £ ^Price, including VAT / £ ^URL ^Datasheet ^Instructions ^Notes | | ||
+ | | BME280 | 13.28 | ~~=round(cell(col()-1, | ||
+ | | ADS1115 | 9.96 | ~~=round(cell(col()-1, | ||
+ | | DN7C3CA006 | 14.04 | ~~=round(cell(col()-1, | ||
+ | ^Total | ~~=sum(range(1, | ||
+ | |||
+ | ===== Asembly and development ===== | ||
+ | |||
+ | ==== DN7C3CA006 ==== | ||
+ | DN7C3CA006 is an analogue PM2.5 sensor, that needs to be installed in a peculiar way. The voltage source of the sensor' | ||
+ | |||
+ | === Existing tutorials using DN7C3CA006 and its variants === | ||
+ | * https:// | ||
+ | * https:// | ||
+ | * http:// | ||
+ | * https:// | ||
+ | * http:// | ||
+ | |||
+ | === Datasheets === | ||
+ | * https:// | ||
+ | * http:// | ||
+ | * http:// | ||
+ | |||
+ | |||
+ | ==== The bunch of transistors that I bought ==== | ||
+ | I bought a bunch of transistors off taobao.com. Here is a summary of their datasheet: | ||
+ | ^Transistor ^$V_{CBO}$ / V ^$V_{CEO}$ / V ^$V_{EBO}$ / V ^$I_{C}$ / mA| Application Notes | ||
+ | | 8050 | 40 | 25 | 6 | 1500 | 2W Output Amplifier of Portable Radios in Class B Push-pull Operation | | ||
+ | | 9014 | 50 | 45 | 5 | 100 | Pre-Amplifier, | ||
+ | | 9013 | 40 | 25 | 5 | 500 | 1W Output Amplifier of Portable Radios in Class B Push-pull Operation | | ||
+ | | 9018 | 30 | 15 | 5 | 50 | AM/FM Amplifier, Local Oscillator of FM/VHF Tuner | | ||
+ | | 3906 | -40 | -40 | -5.0 | -200 |General purpose amplifier and switching applications at collector currents of 10 µA to 100 mA | | ||
+ | | 3904 | 60 | 40 | 6.0 | 200 | General purpose amplifier and switching applications at collector currents of 10 µA to 100 mA | | ||
+ | | 5401 | 160 | 150 | 5.0 | 600 | Amplifier Transistor | | ||
+ | | 9012 | -40 | -20 | -5 | -500 | 1W Output Amplifier of Portable Radios in Class B Push-pull Operation | | ||
+ | | 1815 | 60 | 50 | 5 | 150 | Audio Frequency Amplifier & High Frequency OSC | | ||
+ | | 5551 | 180 | 160 | 6 | 600 | General-purpose high-voltage amplifiers and gas discharge display drivers | | ||
+ | |||
+ | |||
+ | Note that for NPN transistors, | ||
+ | )]. | ||
+ | |||
+ | ==== Table of symbols ==== | ||
+ | |||
+ | ^Symbols ^Meaning | | ||
+ | |$V_{CEO}$ | Collector-Emitter Voltage | | ||
+ | |$V_{CBO}$ | Collector-Base Voltage | | ||
+ | |$V_{EBO}$ | Emitter-Base Voltage | | ||
+ | |$I_C$ | Collector Current Continuous | | ||
+ | |||
+ | |||
+ | ===== External Links ===== | ||
+ | * [[https:// | ||
+ | * [[https:// | ||
+ | * [[http:// | ||
+ | * [[http:// | ||
+ | * [[http:// | ||
+ | * [[http:// | ||
+ | * [[http:// | ||
+ | * [[https:// | ||
+ | * [[http:// | ||
public/raspberry_pi_weather_station_board.txt · Last modified: 2019/01/19 03:56 by fangfufu