lonometer-dump

This project describes, how get data out of the 'lonometer' aka 'VENTUS W030'.

The lonometer is a bluetooth thermometer/hygrometer and it is intended to us an Android/IOS App to read and visualize its measurements. This README contains the basic knowledge that you need to get the data from the device using a linux PC (tested with a raspberry-pi). The perl script I wrote reads the data from the device and writes a shell script containing commands to feed the data to an rrd file.

capabilities

• resolution is 1 degree celsius / 1 percent rH.
• temperature and humidity are measured every 5 minutes, independent from when data is being read.
• the device keeps a history of the last 24 hours (so 288 measured values).
• when reading data, the device always returns the whole set of data.

prerequisites

• linux machine with BTLE-adapter
• bluez with BTLE support (for a raspberry-pi with raspbian, see http://www.ioncannon.net/linux/1570/bluetooth-4-0-le-on-raspberry-pi-with-bluez-5-x/ packages needed to compile bluez: libglib2.0-dev libdbus-1-dev libusb-dev libudev-dev libical-dev libreadline-dev systemd)

steps to read data

activate the BTLE interface

sudo hciconfig hci0 up

scan for BTLE devices

sudo hcitool lescan

after some seconds, the output should show the address of the device

LE Scan ...
AA:BB:CC:DD:EE:FF (unknown)
AA:BB:CC:DD:EE:FF NGE76
AA:BB:CC:DD:EE:FF (unknown)
AA:BB:CC:DD:EE:FF NGE76
AA:BB:CC:DD:EE:FF (unknown)
AA:BB:CC:DD:EE:FF NGE76

do a characteristics scan

gatttool -b AA:BB:CC:DD:EE:FF --characteristics
handle = 0x0002, char properties = 0x02, char value handle = 0x0003, uuid = 00002a00-0000-1000-8000-00805f9b34fb
handle = 0x0004, char properties = 0x02, char value handle = 0x0005, uuid = 00002a01-0000-1000-8000-00805f9b34fb
handle = 0x0006, char properties = 0x0a, char value handle = 0x0007, uuid = 00002a02-0000-1000-8000-00805f9b34fb
handle = 0x0008, char properties = 0x08, char value handle = 0x0009, uuid = 00002a03-0000-1000-8000-00805f9b34fb
handle = 0x000a, char properties = 0x02, char value handle = 0x000b, uuid = 00002a04-0000-1000-8000-00805f9b34fb
handle = 0x000d, char properties = 0x20, char value handle = 0x000e, uuid = 00002a05-0000-1000-8000-00805f9b34fb
handle = 0x0011, char properties = 0x02, char value handle = 0x0012, uuid = 00002a23-0000-1000-8000-00805f9b34fb
handle = 0x0013, char properties = 0x02, char value handle = 0x0014, uuid = 00002a24-0000-1000-8000-00805f9b34fb
handle = 0x0015, char properties = 0x02, char value handle = 0x0016, uuid = 00002a25-0000-1000-8000-00805f9b34fb
handle = 0x0017, char properties = 0x02, char value handle = 0x0018, uuid = 00002a26-0000-1000-8000-00805f9b34fb
handle = 0x0019, char properties = 0x02, char value handle = 0x001a, uuid = 00002a27-0000-1000-8000-00805f9b34fb
handle = 0x001b, char properties = 0x02, char value handle = 0x001c, uuid = 00002a28-0000-1000-8000-00805f9b34fb
handle = 0x001d, char properties = 0x02, char value handle = 0x001e, uuid = 00002a29-0000-1000-8000-00805f9b34fb
handle = 0x001f, char properties = 0x02, char value handle = 0x0020, uuid = 00002a2a-0000-1000-8000-00805f9b34fb
handle = 0x0021, char properties = 0x02, char value handle = 0x0022, uuid = 00002a50-0000-1000-8000-00805f9b34fb
handle = 0x0024, char properties = 0x10, char value handle = 0x0025, uuid = 00002a1c-0000-1000-8000-00805f9b34fb
handle = 0x0027, char properties = 0x08, char value handle = 0x0028, uuid = 0000fff1-0000-1000-8000-00805f9b34fb
handle = 0x002a, char properties = 0x12, char value handle = 0x002b, uuid = 00002a19-0000-1000-8000-00805f9b34fb

so according to https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicsHome.aspx

• handle 0x0024 is for temperature measurement (uuid = 00002a1c matches 0x2A1C in the documentation)
• handle 0x002a is for battery level (uuid = 00002a19 matches 0x2A19 in the documentation)

so reading the battery level is done by

gatttool -b AA:BB:CC:DD:EE:FF --char-read --handle=0x002b
Characteristic value/descriptor: 64

the result is 0x62 - I assume it means the battery level is 100%

reading temprature is done in a different way by

gatttool -b AA:BB:CC:DD:EE:FF --char-write-req --handle=0x0026 --value=0100 --listen

the output can be found in the file dump.txt

• The first 2 bytes count from 288 down to 1 and indicate the age of the measurement (multiply by 5 and subtract 1 to get minutes)
• The 3rd byte corresponds to the channel selected with the sliding switch in the battery compartment (can be 1, 2 or 3)
• The 4th byte corresponds to the temperature (I assume that subtracting 40 gets you to the correct value in celsius)
• The 5th byte corresponds to the humidity (doesn't need to be converted)

usage

use shell script to create rrd files (set the variable 'name' inside the script to the BT device address)

./rrdcreate.sh

use perl script to read data from the BT device

./lonometer-dump.pl -b AA:BB:CC:DD:EE:FF -r /tmp/

the script expects the rrd files in the given directory and puts a file 'update.sh' there which you can execute thereafter