Thank you for your reply, ssmith_c. Let me ask the question again to better understand. The requirements are as follows: ・A graph app to see changes in data ・measured data is about 2 bytes. ・measurement time is more than 24 hours. ・I want to obtain samples as finely as possible. Let me ask again, taking the above into consideration. ①Is iBeacon possible even if the app is in the background? ＞If I were trying to make a data logger, I'd log on the device... ②Does "log on the device" mean a connection via GATT communication? Also, does this refer to "b.", which ssmith_c answered?

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