11 Replies Latest reply on Feb 13, 2012 1:04 PM by Drew Fustini

    Open Source, Open Heart

    Drew Fustini



      I just finished building the Open Heart kit by Jimmie Rodgers:



      4248880792_5f3927805b (1).jpg


      Charlieplexing is cleverly applied so that 27 LEDs are driven by just 6 pins.  The heart-shaped LED matrix could be used with any microcontroller platform.  For those partial to Arduino, Jimmie offers source code for displaying patterns.  I easily hooked up the Open Heart to an Arduino-clone from Adafruit, the DC Boarduino:



      In the source code download, there is also a nifty web-based graphical editor which allows easy creation of new patterns and animations:



      Here's a quick video of my Open Heart running the default animations in the example sketch:



      The video captures some of the unintended LED illumination during a couple animations.  I believe this is just a consequence of charlieplexing, and it is not very noticeable to the naked eye.


      With Valentinie's Day approaching, I think this easy and inexpensive kit has the potential to make a nice gift.  Check out Make's article on making an Open Heart headband that shows the wearer's actual heartbeat:








        • 1. Re: Open Source, Open Heart

          Hi Drew,


          I saw this device in my latest MAKE issue and had not thought of it as a good kit gift for valentines day.  Neat idea.




          • 2. Re: Open Source, Open Heart
            Drew Fustini

            I've added a Polar chest strap receiver chip, so the Open Heart now beats along with my heart:



            • 3. Re: Open Source, Open Heart

              I wonder if the device could be rigged to display my pain levels?

              It would help people around me to know when I am not in a good mood during the day.


              Think about setting these up with different color LED's and then have them triggered by set levels of heart rate.  You could have an incredible light show while you worked out at the local gym.  Think about how much fun kids would have as they try to reach different levels of conditioning all correographed to lights and music.  It could make PE really fun.

              Should be a patent idea in there somewhere.


              Oh well, thanks Drew.


              • 4. Re: Open Source, Open Heart
                Drew Fustini

                Do you mean different single color LEDs in a static configuration?  That would work fine with the existing PCB I think.  Bi-color or RGB would add more complexity but should still be doable.  At some point though, I figure the charlieplexing scheme might be insufficient and different multiplexing scheme would be needed like shift registers.


                I do like the idea of different ways of displaying achievements in physical education or at the gym.  The popular term seems to be 'gamification' where you earn 'badges' for different achievements.  I imagine that you could have 'high scores' for different equipment in a gym.

                • 5. Re: Open Source, Open Heart

                  Hi Drew,


                  I was thinking either two color or full color LED's.  For different activities you want to hit different heart and breath rates.  As you warm up, you would want to hit a set rate to indicate that you are ready.  So you tap the button and the lights go blue.  As you approach the warm up rate they slowly change to red to indicate you are ready.

                  Same with cool down, it would start out red and as you calm down it would fall to all blue.

                  During a workout, you could have them go half and half when you hit your target rate.  If you exceed your maximum limit, they could all go red and blink to alert you that you are doing too much.

                  For data source, I was thinking an ear clip LED sensor.  To get both heart and breath, I was thinking a microphone/earphone combo.  TI sent me some for the DSP board I bought, so I know you could set them up to record on one set and transmit on another.  Using two would let you record the low frequency heart and respiratioin rate while you provide tone feedback to the other set.


                  You know how it is, I saw the post and this idea popped into my head.  I think they used to burn people like that, but thats a different issue.


                  Just a thought,


                  • 6. Re: Open Source, Open Heart
                    Drew Fustini

                    I like the idea about giving the wearer feedback on warm up and activity benchmarks.  I hadn't thought of the ear but that sounds like a good location versus the finger for physical exercise which requires dexterity.  And sound filtering for respiratory rate is very intriguing.




                    • 7. Re: Open Source, Open Heart

                      Has anyone considered the neck.  This would be like the old Pilots Mikes that wore next to the larynx.  You have major artiers in the neck also.


                      Dave M.

                      • 8. Re: Open Source, Open Heart

                        Hi Dave,


                        I did think of using the neck, but considering the issues of positioning the microphone at the right place without restricting movement and air flow lead me to the microphone/earphone solution.  Most people wear the ear buds anyway and TI has a pair that also work as microphones. 


                        Plus, most of the neck microphone were touch to talk.  They had a lot of problems with using them in the aircraft.  Like I said, they restrict movement and have a lot of noise if you did not have the push to talk feature.


                        Still, not a bad idea.



                        • 9. Re: Open Source, Open Heart
                          Drew Fustini

                          Thanks for the ideas.  DAB - do you happen to recall the model for that TI DSP board?  I'd be curious to take a look at the specs.

                          • 10. Re: Open Source, Open Heart

                            Hi Drew,


                            It was the TMS320C5535 eZdsp USB kit.  It currently sells for $99.99 USD.

                            Its a neat little kit with an SD card integrated for recording audio.  I bought mine to analyze the sounds that thunder makes during lightning storms.  I now have a design for getting both the flash, sound and atmospheric vibrations from a single site.  I am currently looking for all the parts I need and waiting for my right arm to heal from a small mishap while building my CNC mill.


                            Hopefully I can get all of these sensors built and installed for the spring storm season.



                            • 11. Re: Open Source, Open Heart
                              Drew Fustini

                              Thanks for the model number.  I was just looking over the product info on it.  The price doesn't seem too bad for all those features.  I saw active noise cancellation listed as one of the applications which interests me.


                              Sorry to hear about your arm - hope it mends well.