Sensor Accelerometer
A quick guide on how you would be able to manually get values from the accelerometer.
For this step just follow the image below to connect the pins to the right slots. Make sure that it is the P9 slots.
Black wire - ground
Red wire - 3.3V
Green wire - I2C Clock
Blue wire - I2C
Purple wire - Configures each sensor to a different register (should not be connected to the beagle board)
Once you connect the BeagleBone to your laptop then open ubuntu and type in the command
ssh debain@192.168.7.2
If it gives out nothing then just wait for a minute and then try again
It will then request a password from you which is temppwd
Now use the below commands to get the required information from the board
i2cdetect -l -- lists all the different busses on the beaglebone
i2cdetect -r 2 -- connect to the i2c 2nd bus, a table to registries will appear and the relevant register names would appear e.g. 18 19
The next step is to set the modes for the addresses on the beaglebone so that you would be receiving the information from the sensors.
i2cset -y 2 0x18 0x20 0x64 -- Setting it to High Power mode
i2cset -y 2 0x18 0x21 0x0c -- Enabling BDU
i2cset -y 2 0x18 0x25 0x30 -- Setting full scale selection to +-16 gs
i2cget -y 2 0x18 0x27 -- Reading this bit will tell you whether the sensor is ready to be read from. If it is then it is ready to be read if it is 0 either you made a mistake or would have to wait and try again in another second.
Repeat these steps with the 0x19 registry for the other sensor.
As for this breadboard, there are 2 sensors we will have 2 registries (being 0x19, 0x18)
Next, you will get the information from the sensor, this can be done by typing these commands into the command line in ubuntu:
i2cget -y 2 0x18 0x28 -- This is getting the Low x-axis which is the smaller insignificant value for the x-axis acceleration
i2cget -y 2 0x18 0x29 -- This is getting the High x-axis which would be the larger more significant value for x-axis acceleration
Repeat this with 0x2a 0x2b for the y-axis low and high and 0x2c 0x2d for the z-axis high and low.
Repeat all the previous steps but with 0x19 to get the reading from the other sensor
###This is an example of how it looks in a command line
Then once you get your values go to the datasheet (Page 57 onwards) and concatenate the values together to get the acceleration. e.g. if you get 0x00 (being your high value), and 0xec (the low value) then to concatenate it would be 0x00ec. Perform hexadecimal to decimal (base 10) conversion and multiply that value by 0.01 to get your acceleration. If the sensor is stationary the x-axis and y-axis acceleration should be 0 but the z-axis acceleration will be 1.