ECG Sensors

[Philip Tsao]

Hi Nikolai,

I am trying to do something very similar for my university project
(biomedical engineering). We are trying to build an ECG sensing
device that will transmit data to the iPhone through Bluetooth. We
are then going to develop an app to display the ECG signal.

I have looked at the iPhone SDK for bluetooth support. They don't
seem to have much, and we can't afford to pay the 100$ developer fee.
If I was a member of the developer program and the "Made for iPod/
iPhone," would I be able to manipulate Bluetooth in this way?

I was also wondering why you had to send the signal from your heart
rate monitor to your breadboard, and then to the iPhone, instead of
directly to the iPhone. I am pretty new to Bluetooth and iPhone apps,
so any help you could give me would be appreciated!

Thanks,
Philip Tsao

[Philip Tsao]

I was also wondering if a different Bluetooth module would work. We
are building our device from scratch and we are using the LMX9838
module from National Semiconductor (http://www.national.com/mpf/LM/
LMX9838.html#Overview). Is there any special work I need to do in
order to get this module to communicate with the iPhone/BTstack? Or
do I just need to use the right protocol (I think I read it was RFCOMM
for BTstack).

Also, if I have two signals I wish to send in real-time, do you know
how I could send them simultaneously over Bluetooth? Or would I have
to just send one signal first and then the other? Thanks for your
help!

Thanks,
Philip Tsao

[Nikolai Onken]

Hi Philip,

thanks for your email and great that you are working on something
similar.

You don't really have to be a member of the Apple developer program
but pretty much can do everything you want with a jail-broken phone (I
don't advocate jailbreaking, but unfortunately this is the only way to
get access to all bluetooth protocols). If you would be part of the
made for iPhone program then yes you would be allowed to use bluetooth
in a way you usually are not (though I don't know if they officially
support RFCOMM).
I just read that Android 2.0 gives you full access - it would be great
to see how we can set up bluetooth there, and start injecting stuff
into the web runtime.

I am sending the data to my breadboard because the T31 sends a
magnetic signal which has to be received by a special Polar chip.
I believe there even is a Polar transmitter which sends data via
bluetooth but I worked with the T31 so have not tried it.

Btstack works with several protocols, RFCOMM even is still
experimental (though I haven't had any issues at all).

In regards to sending two signals, I have not tried it myself - are
you planning to receive data from two or more ECG transmitters?

I hope that gives you some more info in how to get started. I am
curious to see your progress, maybe we can join efforts to get better
bluetooth access to browsers and different phones.

Regards,

Nikolai

[steven]

Hello Nikolai, All,
Apologies for the stupid question as I have no programming experience
myself, but is this something I can create on my phone via an install
in cydia? Looking at some of the videos and tutorials it appears some
of the programs are available on Cydia but other parts require me to
create my own version of the program? Not too sure as Im completely
stupid when it comes to this. I was actually hoping to find a way for
the iphone to pull in heart rate data through a bluetooth monitor but
it appears they currently forbid it via the official SDK. I actually
think there would be a great deal of demand for something like this
and I would definitely pay for this type of app. People who run/cycle/
etc currently only have watches such as Suunto/Garmin/Polar to provide
them HR data however a smart phone/ipod touch could provide more data,
accurate and historical graphing, on the fly training analysis,
possibly GPS, etc to a degree which the above cannot match. If these
companies are able to focus on this market I dont see why developers
dont jump at the opportunity to gain some of that market. Also the
current HR apps on the app store are just garbage. they even have one
where you tap your hr into the screen. I would love to see someone
doing that while trying to run a triathlon.

Also if you guys know of a way for a someone with little programming
knowledge to set up the iphone to begin recieving HR signals from a
monitor I would love to hear it.

thanks.

[Nikolai Onken]

Hi Steven,

hmm, it might be a good idea to get the app on cydia - I mainly didn't
do it yet because it is very prototypal, crashes sometimes and just
served the purpose of showing what you actually can do within the
browser. Unfortunately since Apple doesn't allow you to access the
bluetooth profile we need you still need to jailbreak the device - so
you will have to do some hacking to get it running.

I have setup an IRC channel on irc.freenode.net : #humanapi - drop by
there if you have questions and we can see what to do best.

Nikolai