After my promising start last week in reading data from a blood glucose meter using the IEEE 11073 standard, I've come across my first hurdle. I can read the Medical Device System (MDS) attributes just fine, as well as details of the PM (Persistent Metric) store. Basically, when data is stored on the device to be retrieved at a later date, it is placed in the PM store. I'm now trying to read data form the PM store, but it's not going as planned.
It took me a while to realize that I should be reading from the PM store's segment ID 0 instead of 1. You know, the classic off-by-one issue. Now it's telling me that the meter data is being sent, but I'm not receiving it as expected. My current guess is that the issue may be with WebUSB itself after looking at this Stack Overflow thread. Basically I'm thinking that I should use an event listener to read data from a bulk endpoint, rather than polling it as I'm doing at the moment. The thing is, I'm not sure if WebUSB supports using event listeners for reading data, so now I'm reimplementing everything in regular node-usb.