Thanks for the +ve feedback Geoff,
I agree with you 100%. I had a heart attack last summer so these things are uppermost in my mind. I use the breathing relaxation technique all the time, but now I have biofeedback too.
I wanted something that gave feedback which correlated better with what you are feeling. As I said you can see the leds sync with you feeling the pulse on your neck. The 30 beat average is just to get a value to compare with the target.
I guess this could also be used for athletic training ie set high value targets and get simple visual biofeedback. I haven't tried it for that yet, but I think the chest-strap version of the pulse monitor would be more suitable, to cope with the constant jogging around https://digitalmeans.co.uk/shop/sensors-category/sensors-medical-category/grove-chest_strap_heart_rate_sensor
. So setting upper and lower targets could be useful for training and cool-down.
You need to exercise when recovering from heart problems but within limits. It could help with that too because you can see when it changes over.
Did you see any problems with the code at all? My background is in Biology so I lack some confidence in the coding field.