My name is Chris and I’m a rising Junior at the Bay School of San Francisco. I made the ultrasonic parking sensor for my starter project and the cloud storage system for my main. I chose the parking sensor because I thought I might be able to use it in a project car in the future. The cloud storage system was because I think Dropbox has unfair prices, and Google Drive has Google’s lax privacy policies.
Main Project: Cloud Storage System
Milestone 3: 1TB Hard Drive
In this modification, I connected a 1TB hard drive to my Owncloud. When I first attempted to setup Owncloud with the new drive, the web server needed write permission. The default NTSC format does not allow for ownership of the drive, and in order for a web server to write to the disk it needs ownership. The first step I took was formatting the hard drive to the Ext3 format, which supports ownership of a drive. Code:
sudo chown -R www-data:www-data /media/Disk1o
The “Sudo” part of the code sends the command to the root of the OS, as opposed to my user. “Chown” tells that I am modifying the ownership of the drive, and “www-data” is the web server username. After the formatting, I hooked up the new disk by modifying line 5 of the config file to read from the new hard drive. Code:
/user/pi/www/data
to
/media/Disk1
This just changes where the database is located, and directs Owncloud to the new hard drive instead of the old one. From here I added different users and groups, to show the possible application of Owncloud in a business or school environment. From here, I allocated different amounts of storage for the users, and their groups and admin positions which is doable natively on the web interface. Using Owncloud, I can create an infinite amount of users, groups and admins on my 1TB hard drive. To compare, Dropbox gives corporations 1TB of storage with 250 users for $31420 per year of use. Owncloud also offers a web client, desktop client and mobile apps just like Dropbox does, and thus can serve as a cheaper and possibly better alternative going forward.
Main Project: Cloud Storage System
Milestone 2: Using Native Clients
For this video, I am connecting to Owncloud using the native client, which integrates Owncloud into your computer’s interface for better usage. The client is downloadable from the Owncloud website, and is easy to setup using the same credentials used on the web client. Now, Owncloud appears on the menu bar as well as in your favorites in Finder, just like Dropbox. Owncloud can also give you a progress bar when syncing, a check when syncing is complete, and some many other integration features. Manual server connection is no longer necessary, as the client connects automatically, as well as syncing your files faster.
Main Project: Cloud Storage System
Milestone 1: First Cloud Tranfer
For this milestone, I demonstrated a cloud transfer between two computers. The first step of this is simply setting up Owncloud and determining your IP address. From there, you can simply connect to a server using any software (I used the native software on Mac OSX). After entering my credentials, the computers are connected to the server (And therefore each other) using a third party server connection.
Starter Project: Ultrasonic Parking Sensor
For my starter project I made an ultrasonic parking sensor. The parking sensor uses ultrasonic sound waves to measure the distance to an object, and alert you that it is close. There are two main parts of the sensor: the base and the receiver. Communication between these two parts is facilitated through the screw connectors on both sides. Both sides contain integrated circuits, which are pre-programmed chips serving as the “home base” for all of the sensor’s functions. The two pieces also share capacitors, electrolytic capacitors, diodes and resistors. The capacitors store electrical charge, as do their electrolytic counterparts, which are polarized. The diodes allow current flow in one direction, and prevent it in another. These too have polarity, and their orientation on the circuit board matters. Resistors resist electrical current, with their colors representing their value in ohms. Parts unique to the Base are the quartz crystal, potentiometer, and the speaker. The quartz crystal manages the frequency of the sound, and the speaker produces the actual sound itself. The potentiometer controls the threshold of the sensors, and is adjustable by turning a knob. Parts exclusive to the receiver are the sensors and the transistor. The sensors use ultrasonic waves to sense proximity to an object in front of them, and the transistor turns on and off the circuit board. After I had finished the soldering process, the sensor initially did not work. After spending about an hour troubleshooting, the issue turned out to be a soldered joint having broken loose. Next I will check all soldered joints, for strength and coverage.