概要
Raspbery Pi 3 で動確
- Raspbery Pi 3 と接続
i2cdetect でデバイスアドレスが 0x76 であることを確認
pi@raspberrypi:~ $ i2cdetect 1 WARNING! This program can confuse your I2C bus, cause data loss and worse! I will probe file /dev/i2c-1. I will probe address range 0x03-0x77. Continue? [Y/n] 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- 76 --i2cdump してみる
pi@raspberrypi:~ $ i2cdump 1 0x76 No size specified (using byte-data access) WARNING! This program can confuse your I2C bus, cause data loss and worse! I will probe file /dev/i2c-1, address 0x76, mode byte Continue? [Y/n] 0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef 00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 80: 8c 50 89 1f 6e 32 79 06 50 6f 8a 68 32 00 1a 92 ?P??n2y?Po?h2.?? 90: e1 d6 d0 0b a1 1b 8e ff f9 ff 0c 30 20 d1 88 13 ???????.?.?0 ??? a0: 00 4b 96 00 00 00 00 00 00 00 00 00 33 00 00 c0 .K?.........3..? b0: 00 54 00 00 00 00 60 02 00 01 ff ff 1f 60 03 00 .T....`?.?..?`?. c0: 00 00 00 ff 00 00 00 00 00 00 00 00 00 00 00 00 ................ d0: 60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 `............... e0: 00 58 01 00 16 2b 03 1e 94 41 ff ff ff ff ff ff .X?.?+???A...... f0: ff 00 00 00 00 00 00 80 00 00 80 00 00 80 00 80 .......?..?..?.?Datasheet に書かれている以下のレジスタは変化せず。どこかで計測開始のトリガーをかける必要がありそう。
5.4.7 Register 0xF7…0xF9 “press” (_msb, _lsb, _xsb)
5.4.8 Register 0xFA…0xFC “temp” (_msb, _lsb, _xsb)
5.4.9 Register 0xFD…0xFE “hum” (_msb, _lsb)
Switch Science さんの Python スクリプトで確認
- ここの [Clone or download] で落とす。 git clone するか zip で持ってくるか。
zip で持ってきた場合、以下で解凍
pi@raspberrypi:~/Downloads $ unzip BME280-master.zip Archive: BME280-master.zip aabccb113698c97b02fa4c15735588b1399efb34 creating: BME280-master/ creating: BME280-master/Arduino/ creating: BME280-master/Arduino/BME280_I2C/ inflating: BME280-master/Arduino/BME280_I2C/BME280_I2C.ino creating: BME280-master/Arduino/libraries/ creating: BME280-master/Arduino/libraries/SSCI_BME280/ inflating: BME280-master/Arduino/libraries/SSCI_BME280/SSCI_BME280.cpp inflating: BME280-master/Arduino/libraries/SSCI_BME280/SSCI_BME280.h creating: BME280-master/Arduino/libraries/SSCI_BME280/examples/ inflating: BME280-master/Arduino/libraries/SSCI_BME280/examples/ESP8266_BME280_sample.ino inflating: BME280-master/Arduino/libraries/SSCI_BME280/keywords.txt inflating: BME280-master/LICENSE creating: BME280-master/Python27/ inflating: BME280-master/Python27/bme280_sample.py extracting: BME280-master/Python27/requirements.txt inflating: BME280-master/README.md実行したら温湿度気圧が取れたので、動確としては終了。後はスクリプトの中を読めばわかるはず。
pi@raspberrypi:~/Downloads $ cd BME280-master/Python27/ pi@raspberrypi:~/Downloads/BME280-master/Python27 $ pip install smbus2 Collecting smbus2 Using cached https://www.piwheels.org/simple/smbus2/smbus2-0.2.1-py2.py3-none-any.whl Installing collected packages: smbus2 Successfully installed smbus2-0.2.1 pi@raspberrypi:~/Downloads/BME280-master/Python27 $ python bme280_sample.py temp : 25.74 ℃ pressure : 1013.68 hPa hum : 66.61 ％ pi@raspberrypi:~/Downloads/BME280-master/Python27 $ python bme280_sample.py temp : 25.76 ℃ pressure : 1013.66 hPa hum : 66.56 ％
