RE: Minimise time to send file over BLE

kevin — Mon, 11 Jan 2016 10:38:48 GMT

Thanks for your answer. I did search for the answer to this question like you suggested. Almost all of them suggest decrease the connection interval on the nRF51. Nothing much is mentioned about how to change things the Android app. That being said, is there any thing I can do on the Android side?

Fundamentally, there is something I can do to optimise the data being used and potentially a much smaller file can be sent across. I'll experiment with this method first.

RE: Minimise time to send file over BLE

RK — Sun, 10 Jan 2016 01:49:13 GMT

There's lots of factors involved, but the basic ones are connection interval, ie how often the two devices talk to each other and packets per connection interval, which is the number of those 20 byte packets sent in each connection.

But instead of repeating everything - type 'throughput' into the search box ^^ up there, and you'll see loads of detailed answers to basically this question, this is probably one of the best of them

devzone.nordicsemi.com/.../

but read a few of them, there's lots of information there.

So if you're only getting 1.5kB/s the most likely reason is a higher-than-optimal connection interval which you can probably deal with and possibly number of packets per connection, which may be limited by the android device. Without much difficulty you can log the connection parameters when you connect, they are given to you, and it's not very hard to figure out, with a bit more logging, how many packets are actually going out each time, or just use the wonderful sniffer and look at them.

Also is the UART service optimal for the data you're sending? If it's full range 8-bit data, probably does as well as anything else, if you're really sending some other type of data, you may be able to send less by using something custom.