Mystery Box

After a long hiatus, I finally got around to create another fun project. As I was to return back to India, I wanted to do something special for my girlfriend, something that would take us through the memory lane of our college years.

I settled on the idea of creating a reverse-geocache puzzle cum gift box. The idea is fairly simple and there are plenty of examples on the Internet detailing how to make it. The information at Sparkfun and Mikal Hart's website were particularly helpful. The final outcome is very similar to Mikal's puzzle box.

Components -

Arduino duemilanove

EM-406A SiRF GPS Receiver

Pololo Switch

LCD Display

2x1000mAh LiPo Batteries.

Ornamental Wooden Box.

I ordered the components just 3 weeks before my India trip & knew that it would be a race to finish the construction in that short time-frame. Making matters worse was the fact that I didn't have access to the awesome resources as I did at Georgia Tech. It was a constant game of improvisations & compromises.

For example I spent a good 3 hours in cutting out the slit for display using nothing but just a hack saw and a wood file. Never have I badly felt the need for the Dremel saw tool. (wishlist !)

I decided to prototype everything on a bread board before soldering down the components on a general purpose board. However, in the end I just used a couple of zipties & sawed down my breadboard to make it fit snuggly into the wooden box. Pretty good design, I should say :)

The box opens itself up on the final clue to reveal the gift contained inside it. However something went wrong with my servo motor at the last moment & I had to make a really ugly improvisation. I ended up putting a small lock in front of the box with the intent of giving her the key once we were at the final clue.

The code is fairly simple, but the GPS parser is quite rudimentary & ugly. Perhaps if I had more time I would have done it better/differently.

Project hosted at github.

git clone git://github.com/roguehit/mystery_box.git

Some images -

The final box with the lock !

I had to rip out most of the insides to make room for the gift.

The 8-bit guts. (GPS on the right)

Lots of room

 GPS receiver trying to lock on to the satellites

Sea link, location for one of the clues

AVR Clock

So I have been tinkering with AVR micro-controllers since some time & finally decided to sit down & create a project that's simple enough & uses a few basic components.

Enter the AVR Clock.

Main Parts -
1) Arduino Deumilanove
2) DS1307 Real Time Clock (RTC)
3) 16x2 LCD Screen

Arduino is a low-cost AVR powered platform having a huge online support group & is quite popular amongst hobbyist, artists & educationists. The Arduino community has even created a programming language that reduces the learning curve for people who have no background in coding. I however decided not to use the IDE since I already knew how to program the AVR using avr-gcc based tools.

DS1307 is low power consuming, battery backed chip that can be programmed to hold time & date for a really long time. According to the datasheet, a 3.3v Lithium Ion cell will last for approximately 9 years !!! Plus it communicates to the controller over I2C protocol, further reducing wiring footprints. Sparkfun offers another chip, DS3231, which has an inbuilt temperature sensor & works on 3.3v instead of 5v. I would recommend the DS3231 in case you plan to buy a RTC. I picked the DS1307 code from AVRfreaks.

The LCD uses an industry standard controller & I picked up the code from avr-libc examples itself.

AVR Clock

Code hosted at github.com - https://github.com/roguehit/avrclock

Now that the breadboard prototype works correctly, I will create a custom PCB for the AVR Clock next week.

The first

Blogging has been around for long time. But it never appealed me as much as orkut or ther networking site. .so folks you will be hearing frm me a lot in the comin days.