Arduino + Max 8 heartbeat sensor help for school project.

Hello!

I am a multimedia student working on my last big project and I have decided that Max 8 can be utilized to bring my art installation to life.
We learned a little bit about Max8 a few years ago, so I only have a couple of weeks of experience but I think it is very useful for the realization of my art installation.

I am trying to make use of a heartbeat sensor and arduino to showcase a visual feedback where higher 'stress' shows a more stressfull image and lower 'stress' shows a calm image.

What my art installation is about:
My art installation replicates a therapy office, and I want to utilize this visual medium to add to the conversation as it often is very difficult to talk about what is going on in your life/head. The people who are visiting my art installation I will ask them about their week and about the ups and downs while they look at the visual animation that updates to their mood/stress in real time.

What I have up until now:
I couldn't figure out how to make the visuals update in real time with a big difference between calm and stressful so I used a crossfade between two video's of animations I made (I will add a picture).
The stressful animation is inspired by Andrew Robinson's “Max MSP Tutorial - jit.noise and an intro to procedural animation - Intro to Jitter pt 2” on youtube.

Feedback I got from teacher to what I have now:
The difference between stress and calm was clear but not clear enough/big enough yet.

What I want to achieve:
The data from the heartbeat sensor translates into a smooth transition between a very stressfull and a very calm animation. Based on the therapy stoplight model, I want to use the colours blue/green yellow and orange/red, where blues/greens are the colours used in the calm image and reds and oranges are used in the stressfull image.

What would be a bonus:
If I could use a second set of data (Muscle sensor) I have bought a muscle sensor but I do not know for the life of me how to add it to my arduino, how to solder it and how to use the data efficiently. So my priority is to make sure the heartbeat sensor works.

If people could help me with this I would be so grateful! I am not strong in the programming department unfortunately.

Thank you in advance and have a good day!