31–40 of 51 posts
What's going to matter for audio streaming in an automotive (the case they are concerned about) is the energy consumption in the receiver, not the transmitter. They are measuring the second.
This is killing my in my newest stereo, the bluetooth will sleep if the phone is silent for more than 1 second, like a breathy pause during a audiobook. Then it takes a half second to kick back in. I haven't found anyone with a solution yet.
7.1 Conclusions The purpose of this study was to research and investigate the potential existence of a breaking point where BLE becomes less efficient than BR/EDR in terms of energy consumption. The results from the conducted experiments show that BLE has overall worse energy consumption efficiency than BR/EDR and that there is no breaking point since BLE is shown to be worse.
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This is exactly right from my experience in having worked on a few different BLE devices, one of which you've almost certainly used. If you use it like classic bluetooth, you're going to have a bad time like classic bluetooth. Information in advertising packets (which can be as infrequent as a few seconds) is also used extensively in sensor applications which can last a few years on a coin cell battery.
If you live in the middle ground where you want to maintain connectivity, but sporadically send chunks of data on the order of a few to 100s of k, that's where it gets a bit tricky. BLE is still much better for power than classic in those scenarios, but the protocol isn't really intended for that type of bandwidth, and you might end up with a lot of custom stuff on top.
When advertising every few seconds, like an Apple AirTag does, the energy usage averages about 5uA. That certainly beats the heck out of Bluetooth Classic.
They just have different use cases. Eventually BLE will add a long packet size feature and win out. Between music and firmware uploading, there are lots of use cases nowadays. Nobody wants Bluetooth Classic, it's 20+ years old and uses a whole different stack.
BLE was designed as a super low bitrate intermittent protocol, and named with that application in mind. It was designed to spend 99% of its time "asleep". Not too surprising it's similar power to Classic when doing similar things. But also, a good study to actually measure it!
What does that have to do with energy usage? Well, after some initial setup BLE allows devices to wake up and send data without a lengthy and expensive cryptographic handshake.
Obviously this may not work as well if data is constantly being transmitted. This report tries to figure out approximately where that threshold is.
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This is killing my in my newest stereo, the bluetooth will sleep if the phone is silent for more than 1 second, like a breathy pause during a audiobook. Then it takes a half second to kick back in. I haven't found anyone with a solution yet.
The solution is an aux cable.
diva-portal.org is not a journal, it is simply a repository of all academic texts from Swedish institutions.
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Why use Bluetooth at all? Depending on the details, hiding a wire inside a sleeve should be doable. If you really want wireless, I’d suggest considering something like RFM69 / RFM95 type radios. You can easily find a wide variety of form factors, optionally with integrated Arduino compatible MCU, from Adafruit.
It's a really good point, a wire based sensor eliminates a dead battery and interference as failure points. The Wireless accelerometer feature should come after the basic animation concepts have been ironed out and tested. I really appreciate the reference to RMF* type radios - I had not come across them in my reading.
My pleasure. It’s surprising to me how many makers / hobbyists who need wireless don’t know about them so I make it a point to bring it up any time I can. I’ve built dozens of fun projects using them and find them to work really well for my needs. There’s trade offs between the 69s and 95s, so be sure to read up on adafruit’s site to decide which works better for your needs.
The institution credited, Jönköping University, is notable in Sweden for /not/ being a university and skirting the name issue by being named “Jönköping University” in Swedish as well. Make of that what you will but to me it seems like a con. diva-portal.org is not a journal, it is simply a repository of all academic texts from Swedish institutions.