Changing APP_ADV_INTERVAL when scan request detected

[Jason]

Hi,

I'm making a peripheral device that needs to minimise battery usage.  

My device is essentially a beacon but it allows temporary connections to send a stream of data before closing the connection. I do not think I have enough battery to allow permanent connections that follow the apple design guidelines (220 mAh coin cell and >1 year longevity)

I was surprised to discover that android phones won't reliably connect if APP_ADV_INTERVAL is 10 seconds. With my old samsung S5 I need to reduce the interval to around 2 seconds. 

I have an accelerometer so I was planning to rapidly advertise when the user shakes the device. But maybe it would be better to change the advertising interval when a scan request is detected. Is this possible? Can I detect when my device transmits a scan response? Or is there another mechanism to support this?

Thanks in advance for your help.

-JasonR

[Jason]

No I am not able to connect with 10 second intervals. I am only able to connect with shorter periods (less than 2 seconds.) I see all the adverts, there is not much interference here and the device is very near to the android phone.

I think I have a mistake in my settings. 

[Karl Ylvisaker]

That is strange. If you are certain that you central is seeing these advertisements you should have no trouble connecting.
Does the peripheral generate any error or output any logs that indicate that a connect request was received during the 10 seconds advertising intervals?
Could you provide a sniffer trace of the communication when you are advertising with 10 seconds advertising intervals?

Best regards,
Karl

[Jason]

My python install is broken so I've not been able to test with wireshark yet.

But I tried compiling the SDK17 versions of ble_app_uart_pca10056_s140 and ble_app_hrs_pca10059_s140

with

#define APP_ADV_INTERVAL MSEC_TO_UNITS(10000, UNIT_0_625_MS)

My Samsung Galaxy S5 cannot connect to either example when the advertising interval is 10 seconds.

My iPad mini 5 can connect.

[Mishka]

Hi,

this makes me think that this is the Samsung scanning parameters which prevents it from connecting successfully. What app do you use for that? Could you give the Samsung a try with the nRF Connect for Mobile please?

[Jason]

Hi, this is with nrf connect android app.