[Cyborg] Heart Spark!

Eric Boyd mrericboyd at yahoo.com
Sat Dec 18 15:58:31 UTC 2010

The Heart Spark pendant is finally ready!  I've been working on various 
versions of this thing for three months, and before that on various 
versions of the "pulse choker" for like a year.  I am happy to finally 
have something to sell!  It's been a super huge amount of fun making it, 
of course, and I've learned so much.  Thanks especially to Chung-Hay for 
all the great hacking sessions at noisebridge, this project would never 
have begun without you.  Thanks also to Leigh, Ewan and Liz for 
providing various forms of assistance at hacklab.


Believe it or not the Heart Spark code is running up close to the limits 
of the Arduino (ATMEGA168) - there are 1300 lines of code, not including 
the libraries I use!  About half of them are the logging stuff, it's 
quite complicated to get data into and out of the EEPROM in a way that 
makes it useful later.  But a good chunk of the code is also having many 
different ways to blink the LEDs, and there is a lot of code that deals 
with keeping power usage low, since the pendant only has a coin cell 
providing energy... though much more work needs to happen on that front.

I'm hoping to get a logging version for sale sometime late January.  I 
do have logging working, but it's really rough in terms of user 
interface so far, and also only "every heart beat" mode works right now 
(the other "average heart beat each minute" would let you log data for 
over a week before retrieving it, instead of needing to retrieve after 6 

Anyway, I'm happy to answer any questions you might have.


p.s. Heart Spark made the makeblog!

I'm kinda sad that they picked such a poor image from the wide selection 
that is available, but on the other hand that music video is pretty 
awesome, I am thinking that I should recreate it :-).

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