Remember Your Birthday For Fifty Years

Our Coin Cell Challenge competition has turned up some amazing entries, things that we wouldn’t have thought possible from such meagre power sources. Take [Vishnu M Aiea]’s entry for instance, a device which he claims can light up as a birthday reminder every year for up to fifty years.

At its heart is a modified Arduino Nano clone that draws a measured 608 nA from a CR2450N. From the specification of the cell he has calculated the 50 year maximum figure, as well as a possible 29 years for a CR2032 and 64 years for a CR2477. He does however note that this does not take self-discharge into account, but you can probably afford a new battery in a decade or so.

The Arduino clone carefully selected for its “P” version low-power processor has had its serial bridge IC removed to achieve this power consumption, as well as a voltage regulator and some discrete components. Interestingly he notes that the ATMega168P is even more frugal than its 328 cousin, so he’s used the former chip. A selection of internal flags are set for minimal power consumption, and the internal oscillator is selected to use as low a clock speed as possible. There is an Intersil ISL1208 low power RTC chip mounted on a piece of stripboard to provide the timing, and of course an LED to provide the essential birthday alert.

When the LED lights for the big day there’s always the hope you’ll receive another coin cell, this time powering an edge-lit musical birthday card.


18 thoughts on “Remember Your Birthday For Fifty Years

  1. In 58 years, I’ve never forgotten my birthday. Even if I did, someone in the family will remember. Plus, my great, great, great grandfather died on the same day, 103 years before me.

    Martin Luther King III, Weird Al Yonkovitch, Amanda Sternberg (from the first, “Hunger Games” movie) also share the same birthday, so there re plenty of Wikipedia entries I can check.

    Catherine Deneuve and Louis Riel were born on the day before mine, so that’s backup.

    I’m not sure I’ll be around in fifty years to see if the battery lasts long enough.


    1. If you are worried about the device outlasting you, I guess you could always stick these on a tombstone as a nifty memorial marker! I wonder if a solar cell and supercap would make it last longer or if they end up degrading faster than the lithium battery…

  2. Personally thought of combining the two projects somehow to give my kids a birthday card with my voice wishing them a happy birthday from their living father that COULD outlast me. Sure, a video or MP3 could do the same, but this seems more memorable. Like the tombstone idea as well. Reminds me of some previous ideas along thatline.

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