Posts tagged with beaglebone black

Vision Based Line Follower using opencv

The robot is powered by beagleboneblack using a 1500mAh Li Ion Battery with a differential drive mechanism.

Best tutorial for BeagleBoneBlack

For a long time I was searching for a good tutorial for BeagleBoneBlack. Since the community is little less for the BBB it was a little hard to get started. But I found a book which is very useful to get started (in my opinion). {every book is unique in its on way}.

"Exploring BeagleBone Tools and Techniques for Building with Embedded Linux" by Derek Molloy.

Here is link to his homepage where he listed almost all contents in the text. The book cover almost every basics you need to know to get started. (BBB, Electronics, Linux, Cross compilation, Git, Opencv, ...)
Most of the other books and tutorials focus on the javascript tool (node). But I didn't feel so good with it. This book mainly focus programming the BBB using c which I feel good. You will find an e-book here.

A Differential Drive Mobile Robot using BeagleBone Black

Finally start working properly. Need a better voltage regulator and a better battery pack! Voltage spikes when BeagleBoneBlack starts. After a while the BBB will shutdown due to voltage fluctuations… :-( WiFi module in BBB is drawing so much current.

BeagleBoneBlack ADC

Follow the instruction to enable the ADC and read outputs from the file.

echo  BB-ADC > /sys/devices/bone_capemgr.9/slots

(*There may be slight variation for directories. Figure this out if not working.) Verify whether ADC is loaded by

cat /sys/devices/bone_capemgr.9/slots

Read ADC value by

cat /sys/bus/iio/devices/iio\:device0/in_voltage0_raw

Here AIN0 (PIN39 on P9) is connected to a potentiometer. Do not exceed the voltage above 1.8V. This will damage the BBB.
Its a 12 bit ADC. So maximum value will be 4096. To calculate value in voltage,

(1.8/4096) *ADC_Value

I wrote a bash script to do this work.
For this script to work install bc on BeagleBoneBlack. bc is a small program to do mathematical calculation from terminal.

apt-get install bc

Save the above bash script to a file (adc_bash) and set permission to execute by

chmod +x adc_bash

To run it every 0.5 second,

watch -n 0.5 ./adc_bash

Once finished with the ADC you can unexport it. But it will cause a kernel panic. So its better not to do it. So the best way  is to restart the BBB or leave it as is. If you want to unexport it,

echo -7 > /sys/devices/bone_capemgr.9/slots

where 7 is the number corresponding to BB-ADC in

cat /sys/devices/bone_capemgr.9/slots
For more detail refer here.

BeagleBoneBlack GPIO Push Button + LED