Minimal ECG using an Arduino and Xoscillo

http://codinglab.blogspot.be/2013/07/my-heartbeat.html

by Jare • 13 years ago

55 21 13 years ago

codinglab.blogspot.be

JshWright3• 13 years ago

That's an absolutely phenomenal trace... Obviously he's working under somewhat idealized noise conditions (as he described), but that trace is _cleaner_ than what we get out of the portable ECG monitors we carry in the back of ambulances (it also has much higher resolution). These are monitors have a price tag that you'd be more familiar with on a new car...

Don't get me wrong, I'm well aware that there's a big gap between some wires in a breadboard and a ruggedized, battle tested 12-lead. I'm not complaining about the cost of our Lifepacks; rather I'm ust blown away at how great that trace looks with such rudimentary equipment.

I'm gonna have to 'borrow' some electrodes from the station and give this a shot myself...

xchip6• 13 years ago

Hi, I'm glad to hear that, I'll be happy to help if you plan to build one!

As for the idealized conditions, if I gently pass my finger on my laptop's aluminum case I can feel the 50hz hum, so that is why I have to unplug it to get that signal, it may be a laptop's issue. I will check with a desktop and post my results.

tonyarkles• 13 years ago

That sounds a lot like your laptop's chassis might be hot instead of grounded. Possibly an issue with the wiring in your house?

kryten3• 13 years ago

50hz is pretty easy to knock our with a simple RC low pass filter. That should make a difference but it will probably attenuate the signal so you will need an instrumentation amp.

2 hours later... Ahh commercial grade design and massive BOM.

Great work at keeping it simple :)

goblin89• 13 years ago

(So that's where that hum comes from. Been wondering for a long time.)

JshWright3• 13 years ago

Which lead was the picture from? That biphasic morphology of the T wave is a little unusual. Do you have an older ECG to compare it to?

dodo53• 13 years ago

this would be a cool school science lab experiment

kryten3• 13 years ago

Great work! This is why I come here :)

I built a pulse oximeter as my final year project at university and have been rather obsessed with medical electronics since.

I've always wondered if it's possible to build your own ultrasound sensor. Rather complicated devices though.

dorfsmay2• 13 years ago

I am assuming you do the A/D conversion with the electronic board, and then treat the digital signal with the Arduino?

How difficult would it be to wire your A/D conversion unit to do USB? Then any laptop, or even a smart phone could do the UI part. Or am I missing something?

xchip6• 13 years ago

The arduino has an ADC conversor and sends it with no posprocessing at all to the PC. This could be easily used with a smart phone indeed, in fact that is my next step :)

dorfsmay2• 13 years ago

I hadn't realised arduino came,or could have an option ADC. This is really cool. Thanks!

cnvogel• 13 years ago

There's prior art on that one... (using the microphone input as a ADC, sending power to the preamp via the headphone output)

http://web.eecs.umich.edu/~prabal/projects/hijack/

jentulman• 13 years ago

I'm good enough to follow along a diagram and build stuff I find online, but have no real clue as to the electronics.

Given I have a neglected arduino kicking about and a paramedic I could probably get some electrodes from how far removed is this kit from knocking up a very basic 'brain controller'?

I've often fancied feeding some 'thoughts' into Ableton for some synth tweaking fun.

[edit] thought I should actually do some searching on the subject and I just found the openEEG project which has some info in that direction.

xchip6• 13 years ago

Yeah, another thing to try is to connect it to my head to see what I get.. I'd need to increase the gain a bit though

DanBC• 13 years ago

Is it still good practice to have opto-isolators on anything that you're wiring up to your body?

Hydraulix989• 13 years ago

I would DEFINITELY use opto-isolators (my EEG BCI had them) and would always run the ECG on a laptop with its AC adapter _unplugged_. Do you really want to risk even a small chance of electrocution?

Minimal ECG using an Arduino and Xoscillo

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