Real Heart Monitor

[Moshe Glickman]

If you have the audio of it you could drive the visualization off the audio. There are several tutorials for that.
Alternatively, I think you can use text animators to drive a visualization using a text layer. I don’t have access to AE right now, but I’ll look into it when I do.

[Anders Hattne]

I don’t think you could do anything in real time with After Effects since everything requires rendering.
Not quite sure what you want to do, but I assume you have the heart beats as audio (creating some kind of cardiogram), in which case you’d want to use the keyframe assistant to convert audio to keyframes.
(Once you have that I guess you’d need to use the “linear” expression to adjust the resulting values to the range you want to work within.)
That value you could either use with an expression as source text
for a text layer.. or (for a cardiogram) to change the y-position of the brush in the “write-on” effect whilst the x-position runs over time.

About that external document have a look at this tutorial, might be usefull!
https://www.graymachine.com/v3/19-expressions-and-external-documents.html?3491b009633ca8ff33b2bbcc7d694b42=f1240da6048a7b6c72721ccbf0d2097e

[Scott Novasic]

Just a note to add, ‘rendering’ happens FASTER than realtime for a lot of things in AE.

SuperNova
Animation & Visual Effects
Scott Novasic
Los Angeles Ca
web:https://web.mac.com/finaleffects

[Mark Suszko]

Check the free stuff section of the COW for some plug-ins that animate bar graphs and meters based on sound.

The oscilliscope/ ECG images of a heartbeat have a characteristic “double-sharkfin” sawtooth shape, for non-scientific entertainment purposes, all you need to do is draw that shape (GIS examples of the trace on google), and vary the spacing of the re-draws to match the different rates. The size of the beats stays pretty much the same, person to person, just the rate or interval between beats changes, making them closer together and “squished”.

You could make it look more like a real trace by adding some trail fx/decay to a glowing dot and making it track thru the trace shape using keyframes. Or for a strip recorder look, draw the sawtooth pattern out in a long repeating strip and animate it passing by in a loop, perhaps with a wipe or window cut out above it on another layer to reveal it as it passes by.