HID keyboard drains iPhone battery quickly

RE: HID keyboard drains iPhone battery quickly

Jeff — Thu, 30 Oct 2014 17:29:13 GMT

Thanks. I submitted a bug report to Apple a while ago and they replied asking for logs so they may be working on a fix on the phone side already. I will see if they fixed it in the next iOS release.

RE: HID keyboard drains iPhone battery quickly

Asbjørn — Thu, 30 Oct 2014 09:24:37 GMT

Nordic has got a free sniffer to check the timing and content sent across the BLE link itself. It really helps us to know what timing parameters that's actually used, what kind of packages that' being sent and so on. If you have confidential content that you are concerned about for doing a sniffer trace and sending it to us I would ask you to open a case in the closed Nordic support system. There your information will be kept confidential.

RE: HID keyboard drains iPhone battery quickly

Jeff — Mon, 27 Oct 2014 18:58:15 GMT

I attached the capture of the HID activity in the original post. I cannot post the .cfa file because it contains confidential data that I cannot remove.

RE: HID keyboard drains iPhone battery quickly

David Edwin — Mon, 27 Oct 2014 10:54:10 GMT

Jeff, A sniffer trace would really help here. The suspend is understandable but I do not see why the iOS is sending the Exit Suspend.

RE: HID keyboard drains iPhone battery quickly

Jeff — Fri, 24 Oct 2014 17:24:59 GMT

The local device is a nRF51 using HID over GATT. I did not measure the nRF51 power, only the battery % on the phone side. With no keyboard activity and the phone screen always off, the phone battery drops from 100 to 85% in 14 hours. If I do not have the HID service enabled but only ANCS, the battery drops 5%. The only BLE traffic I see from HID is the constant Suspend/Exit Suspend from the phone. I cannot find any way to stop the phone from doing this.

RE: HID keyboard drains iPhone battery quickly

Asbjørn — Fri, 24 Oct 2014 11:50:31 GMT

I'm not sure if I understand your setup here. The local device you refer to is a nRF51-chip with some keyboard code? Do you see difference in power consumption on the nRF51-device or on the phone side?

By how much and how do you measure it?

RE: HID keyboard drains iPhone battery quickly

Jeff — Thu, 09 Oct 2014 17:32:26 GMT

Thank you for the reply. I checked the power consumption of the local device and it is not draining noticeably more power in the keyboard case. The power drain is on the phone side presumably from waking up to send the Suspend/Exit Suspend commands continuously. I was hoping someone can confirm this problem with their phone or with a BLE keyboard with a different chip so I can be sure it is an iOS problem.

RE: HID keyboard drains iPhone battery quickly

Asbjørn — Thu, 09 Oct 2014 13:08:15 GMT

May I ask you to do a sniffer trace of the two different setups. The different power consumptions must be related to the actual connection parameters and radio activity. A sniffer trace would give a good indication on how much of a difference and potentially what the difference is between handling the two setups. Have a look at the sniffer available here.