When I initially started writing code for the Seeed Studio Pulse Oximeter I found that I was getting no pulseOximeter_Heartbeat notifications and it seemed to take an awfully long time to get pulseOximeter_ProbeAttached or pulseOximeter_ProbeDetached notifications.
I was powering the kit from the USB port on my development desktop box via a USB Client SP Module. While doing some research I read this post. I then swapped to one of the USB ports on the mother board and the problems went away. I’m going to get a USB Client DP Module so this issue is permanently resolved.