Regarding the individual profiles and settings "camera in the back." If it is always necessary for the highway and the city to choose the same thing, then now everything is correct. It is not entirely clear whether there are occasions when the city needs only cameras in the back, and on the highway all the cameras. Or vice versa.
Concerning the synthesizer. The fact is that the synthesizer fails to input files, it receives lines of text. I therefore mentioned this.
Regarding battery consumption. The thing is, iOS doesn't care about what happens after the Location Service is extinguished. That is, he extinguishes it and further it is the concern of users or a programmer to pick it up. But thanks for the link, we will integrate. We will try to do the next release on energy saving.
Well, I just suggested, maybe someone will be important only in the city or only on the highway. In principle, this is not the key point :)
Synthesizer - of course, does not receive. But there is the usual function of playing sound from a file. Those. first start the sound and after it the synthesizer. The sound initializes the audio channel with the bt device and while it is open, the synthesizer plays speech. As I said, the sound channel does not close immediately, it takes 1-2 seconds. We need to check how it will work. I could drive a test version on my phone - make a button to play the speech and on / off the file with sound.
I didn’t really understand the location service. As I understand it from reading the manual diagonally, the application sets the accuracy and frequency of updates, and ios calls the application callback. Right? Those. in the case when I sit in the office, he constantly updates my geolocation, using up the battery. What I guess you can do:
1. By timeout without movement, ios is informed that it is necessary to wake the application when the phone leaves the specified region. In this case, turn off the update of the geolocation, i.e. ios stops pulling callback with position update. Further, as I understand it, the tricky ios mechanisms begin to work, which, without much energy, understand when the geolocation changes. I suspect a cellular signal, a wifi network, etc. are used. I’ll come an example: we buy a movie ticket at the Rambler box office, add it to the wallet. Then you can walk with him for an arbitrarily long time, this does not affect the battery in any way. But as soon as you come to the movie theater - the ticket appears on the lock screen. Those. the device can work with geolocation and not eat the battery. As soon as the phone has left the specified region, ios wakes up the application and reports the update of the geolocation. Next, the usual mechanism for updating the position is turned on.
2. Use bt device as a trigger to enable geolocation updates. Those. The device is connected - we are starting to update. Disconnected - turn off the update and go into hibernation.
These options are not mutually exclusive, i.e. It would be nice to have both in the application. Who has a helmet / handsfree - he may want to turn on the device, who does not have bt devices - can set the timeout of inactivity and the radius of the region. What is needed is a radius - in buildings a geo-location can show strange things and the position can change +/- kilometer. Well, here in general, everyone will be able to set himself.
Another moment appeared, information from a colleague already. While talking on the phone in a helmet, messages wedge into the conversation. Of course, you can adjust the volume, but then at a speed with wind noise you just can’t hear anything. It seems that here you can either give a sound signal (similar to how Yandex cards ring to the camera) or use vibro. Again, you will have to do a menu item with settings. Unfortunately, this is inevitable and over time, the settings menu will grow significantly. Here it is important to build it correctly and the most important thing is to set the optimal settings by default, so that most users would not have to understand the intricacies of the settings.
By the way, I forget to ask everyone: where did the source of the cameras come from? And how often is it updated?