The Idea: To fabricate an LED POV LEDClock for the Jogger's Park located next to our apartment building in Mumbai, India. There will be no moving parts, just a column of LEDs hung up on a tall coconut tree. People jogging/walking past can just swing there heads and can see the time due to the POV effect. PS. Recently in 2011, a coconut tree claimed the life of a local resident while he was out for a walk in this park - news article.

Persistence of Vision seems to be is required to complete this Persistence of Vision Project :P .. so here we go..

References:

1. Circuit Cellar 43 (February 1994) - In the eye of the beholder - Displaying Messages with the LightStick II - Shaun J. Greaney
2. http://forums.parallax.com/archive/index.php/t-103500.html
3. United States Patent 4470044 - Momentary visual image apparatus - Bill Bell

30 October 2011

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Management  (process/time/money)	Hardware (mechanical/electronics)	Software (the code)
Available Resources: 2 hrs of my productive time every week (not including time spent thinking about the project while travelling/exercising/eating/day dreaming) Available Resources: Monthly expenditure limit: ~3000 Indian Rupees (approx 60 USD) Use Google Docs Spreadsheet to track time and money spent Use Freeware tools: Eagle, Arduino, Google Services to design and document Use pcbpower.com for PCB fabrication - expensive but convenient and fast SHOULD WORK ON AT THE MAX 3RD ITERATION OF PCB Use components locally available from Lamington Road, Mumbai - Fax component list to Visha Electronics and get stuff from them if possible. Get Prof. Atul Mody's help in formalizing the calculations for frame rate - understand the Physics of the situation The main of the project is to figure out the process for all future projects - a way to set the pace to keep the fun intact without stressing me out - without compromising on the documentation	Use perspex tube - borrow from DVG , a thicker version for what he used for his Batteryless Dice Perspex tube to be fixed high up to a coconut tree using thick long cable ties, so need groves on the tube to fix 3 ties on the top and and 3 ties on bottom end. Would need to ask a coconut wala to help me put this up - or if everything goes as planned I can do it myself, there is a good chance that I would be to climb that tree myself - thanks to the chin-up bar :) Use ATmega168 (Arduino compatible, that's why) No Charlieplexing - drive leds by turning pins on off Column of 7 LEDs Use SMD NPN transistor like BC547 to control LEDs - or use some standard led driving method LM2576 to be used for powering the circuit - we have 1.5Amp 150uH SMD inductors already - will need 2 - 3.3V version for powering the micro and ADJ version to set the power for LEDs Use diffused 10mm Blue LEDs for revision 1 Infrared receiver diode to set the clock from a far using a simple RC5 infrared remote (will only work at night I guess). The remote will also be use to set the led frame change rate (the most comfortable rate must require the minimum neck swing speed - depends on the height of the tree and the distance of the selected tree from the jogging track) CR2303 coin cell to maintain time when mains power is off - use I2C RTC Chip (easy coding) Worries: Power Supply available in the park is from a nearby spherical lampost's box - 230V AC, will need a nice 12DC adapter How to weather proof? silicone gel to seal the ends? use finolex cables? Wishful thinking: RC5 wireless bootoader ;)	Use Arduino Remote will need some password

Todo for next week:

15 January 2012

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Just thought of using a weather proof NMEA GPS Module instead of CR2032+I2C RTC. This will do away with the hassle of manual time adjustments or changing the coin cell every time it runs out. Of course it will increase the cost the system but will increase its ease of use and reliability immensely. Will use a GPS module of this kind.