A Touch of Light

A step towards enlightenment for those living in the world of darkness.

A Young India Fellowship Initiative in collaboration with University of Pennsylvania


      





Tuesday, November 29, 2011

Test Drive-1: GET, SET……… GO!!!!!!!!!!


After the hard work of one and a half month finally we finished first phase of our project. We have designed the viSparsh v1.0. The belt includes a plastic box which contains PandaBoard, Mbed and Voltage Convertor and the Kinect fixed at the front of the belt. Currently we are using three vibration motors on three sides which we plan to increase to six in version 1.1.

We had our test drive today in our hostel and it worked exceptionally well with no false alarm. Some of the other fellows helped us in shooting the video and becoming the obstacles. Here is the video for this test drive-






Power Supply Issues

After powering the circuit from AC mains, it was time to switch on to batteries as the viSparsh belt would be mobile. So, we purchased a Chinese 12V 2100mAh battery pack to run Kinect and used 7805 voltage regulator to power mbed and PandaBoard with 5V. The batteries were drained out in a couple of minutes and situation got worst after recharging it. Hence, this Chinese battery proved useless for us.
We, then, used 8 AA size Kodak 2100 mAh rechargeable cells. Though it powered our setup for 15 odd minutes but not what we required. Then we got 8 more to power Kinect separately. Still, the power dissipation from 7805 was huge and we thought why not to eliminate that. As one cell is rated 1.2V (though it measures between 1.3-1.4), so we connect 4 cells in series to draw slightly more than 5V from it.
Here is the final number of cells we have used in the project:

1. Mbed:                  4 AA Size 1.2V 1000mAh          Output: Slightly more than 5V
2. PandaBoard:        4 AA Size 1.2V 2100mAh          Output: Slightly more than 5V
3. Kinect                  8 AA Size 1.2V 2500mAh          Output: Slightly more than 10V

Here, we were able to eliminate 7805 voltage regulator from our circuit and hence we minimized the power dissipation.We tested the belt for around half an hour and it worked perfectly with this configuration.
We may add 4 more cells in parallel to power PandaBoard.

Another option we may consider is to order a customized battery with our specifications.

Booting Ubuntu on Pandaboard EA3

STEP1: Download the Ubuntu image
Use this link to download the pre-installed image of ubuntu 10.10. 

STEP2: Prepare the SD card
Insert the SD card in your PC and unmount it. Then use this command to copy the pre-built image on the card.

COMMAND:
sudo sh -c 'zcat ./ubuntu-netbook-10.10-preinstalled-netbook-armel+omap4.img.gz|dd bs=4M of=/dev/sdb; sync'

STEP3: Download and copy required u-boot and MLO files
For Pandaboard version A2 and later follow these instructions. In our case we had a EA3 version so we followed it.  

2.      Untar with "tar -jxf panda.tar.bz2"
3.      Mount the first partition of the imaged SD card
4.      Copy MLO and u-boot.bin (extracted from the tar file) to the mounted partition.

STEP4: Boot from Pandaboard
Now unmounts the SD card and insert it in Pandaboard and give it the power. It shall start booting.

STEP5: Now use the same procedure to install OpenNI and Kinect that we used for BeagleBoard.



Tuesday, November 29, 2011

Test Drive-1: GET, SET……… GO!!!!!!!!!!


After the hard work of one and a half month finally we finished first phase of our project. We have designed the viSparsh v1.0. The belt includes a plastic box which contains PandaBoard, Mbed and Voltage Convertor and the Kinect fixed at the front of the belt. Currently we are using three vibration motors on three sides which we plan to increase to six in version 1.1.

We had our test drive today in our hostel and it worked exceptionally well with no false alarm. Some of the other fellows helped us in shooting the video and becoming the obstacles. Here is the video for this test drive-






Power Supply Issues

After powering the circuit from AC mains, it was time to switch on to batteries as the viSparsh belt would be mobile. So, we purchased a Chinese 12V 2100mAh battery pack to run Kinect and used 7805 voltage regulator to power mbed and PandaBoard with 5V. The batteries were drained out in a couple of minutes and situation got worst after recharging it. Hence, this Chinese battery proved useless for us.
We, then, used 8 AA size Kodak 2100 mAh rechargeable cells. Though it powered our setup for 15 odd minutes but not what we required. Then we got 8 more to power Kinect separately. Still, the power dissipation from 7805 was huge and we thought why not to eliminate that. As one cell is rated 1.2V (though it measures between 1.3-1.4), so we connect 4 cells in series to draw slightly more than 5V from it.
Here is the final number of cells we have used in the project:

1. Mbed:                  4 AA Size 1.2V 1000mAh          Output: Slightly more than 5V
2. PandaBoard:        4 AA Size 1.2V 2100mAh          Output: Slightly more than 5V
3. Kinect                  8 AA Size 1.2V 2500mAh          Output: Slightly more than 10V

Here, we were able to eliminate 7805 voltage regulator from our circuit and hence we minimized the power dissipation.We tested the belt for around half an hour and it worked perfectly with this configuration.
We may add 4 more cells in parallel to power PandaBoard.

Another option we may consider is to order a customized battery with our specifications.

Booting Ubuntu on Pandaboard EA3

STEP1: Download the Ubuntu image
Use this link to download the pre-installed image of ubuntu 10.10. 

STEP2: Prepare the SD card
Insert the SD card in your PC and unmount it. Then use this command to copy the pre-built image on the card.

COMMAND:
sudo sh -c 'zcat ./ubuntu-netbook-10.10-preinstalled-netbook-armel+omap4.img.gz|dd bs=4M of=/dev/sdb; sync'

STEP3: Download and copy required u-boot and MLO files
For Pandaboard version A2 and later follow these instructions. In our case we had a EA3 version so we followed it.  

2.      Untar with "tar -jxf panda.tar.bz2"
3.      Mount the first partition of the imaged SD card
4.      Copy MLO and u-boot.bin (extracted from the tar file) to the mounted partition.

STEP4: Boot from Pandaboard
Now unmounts the SD card and insert it in Pandaboard and give it the power. It shall start booting.

STEP5: Now use the same procedure to install OpenNI and Kinect that we used for BeagleBoard.