I have a battery monitoring device for our RV called a PowerMon 5S. It has to be in the battery compartment, given it's wired directly to everything, which means it's in a bad place for Bluetooth.
There's no external antenna port, so the only thing I can think of is to add a Bluetooth LE repeater or extender. Is this possible? Seems that when I search on it all I get are devices with RCA jacks to plug headphones or audio into.
Preferably, a 12v device that I can mount in the battery compartment would be optimal. But, even a 110v device I can put inside would be ok.
Ideas?
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I have a headset that I use on two devices. Each time I wish to switch from one device to the other (about once a week), I need to resync the bluetooth to that device.
I'd like to stop having to do that and I'd rather not buy two headsets but am more interested however in possibly purchasing one USB Bluetooth Adapter and move that instead, as needed.
My question is, will that work? Can I purchase one single bluetooth USB adapter and move that instead, and still have the headset be properly sync'd with each device as I move it from one to the other?
Is it possible to make a peripheral scan for advertisments while connected to a central? It seems like it is either scanning for advertisments or have your peripheral connected but I need to do both. The peripheral should be able to report RSSI measurements from advertisements it picks up.
I'm using 'bleno' for the peripheral and 'noble' for the scanning on a linux box (bluez)
The answer to this differs depending on the version of Bluetooth that your device is on.
For Bluetooth v4.0:
A peripheral cannot scan at all, whether in a connection or not. The peripheral can only send out adverts or accept incoming connections. For more information you can have a look at this document, page 18:-
http://chapters.comsoc.org/vancouver/BTLER3.pdf
For Bluetooth v4.1 onwards:
A device can be in central and peripheral role at the same time. By implication, this means that if a peripheral is connected to a central device, it can still scan for devices in it's "central mode". More information can be found in this link, page 5:-
http://www.ietf.org/proceedings/89/slides/slides-89-6lo-4.pdf
So in conclusion, if your device is BT v4.1 or newer, then this is dependant on the chip manufacturer, and if it is v4.0, then no, because the Bluetooth specification does not allow it.
I'm writing (and copying) some Bluetooth LE scanner software to find and connect to a heart rate monitor. I used to be able to find this device by using scanForPeripheralsWithServices method to perform a generic scan by setting services to nil. But in the recent few days, I noticed that my same Bluetooth LE device (my heart rate monitor) can no longer be scanned (perhaps it is not advertising the same way it used to?) but my iPhone can still pair with it under settings and can connect to it with commercial apps such as "Polar Beat" and "Strava". So what changed? Can a Bluetooth LE device stop advertising and still be connected to (paired with) and share data as a peripheral?
The strange thing is that your device doesn't advertise.
However, it's normal that your iPhone can connect to it because the smartphone executed "bonding" procedure in the past. Bonding is another security procedure than simple pairing. With Bonding, heart rate device and smartphone exchanges keys and store them in a non volatile memory so that they can connect quickly.
With simple pairing the keys are temporary and advertising is needed.
I've got usb cable plugged to my computer, which D+ and D- pins are connected to multimeter. I want to send some raw bytes to get some voltage.. is it possible at all?
I'm 99% sure that usb port I've plugged cable in is something like /dev/bus/usb/002
I know that there was possibility to do the same with LPT or RS232 ports.
RS232 and LPT are not bus ! USB devices need to be addressed in order to become reachable.
Maybe unloading and reloading usb driver that drive your usb host... or trying to make a reset on usb hub host...
For doing this kind of operation on usb port, you have to break usb kernel driver and whipe all addressing operation to address directly the chipset...
At all, due to USB concept, I'm not sure you may successfully hold some power state on outlet.
For playing with that kind of physical IO, two solution:
Install a low-cost RS-232 <-> USB adapter
or better
Buy an Arduino micro-controller for prototyping and development.
I'm nearly 100% sure that you can't send anything down your USB lead unless you actually have a device at the other end. If you still want to play with this, get a cheap memory stick, break the casing off it [not too roughly], and measure whilst doing a large file-transfer to the memory stick, or some such.
But I'm not sure your multimeter will show much, as they tend to be a bit slow, compared to USB rates.
USB uses pull-up / pull-down resistors on the data lines to detect whether or not a port is connected (1.5k pull-up to 3.3v on the device side, 15k pull-down on the host side IIRC). The exact connection depends on the device speed.
So if you connect an appropriate resistor, the host should attempt to start signalling. Because of the data-rate, you might not be able to see that on a multimeter; an oscilloscope would be more appropriate.
If you want to by-pass the normal USB protocol and just blindly send data, I think you'll need to get your hands dirty and write code to bypass the usual device drivers and access the USB hardware directly. Even then I'm not sure what's possible - the USB hardware is a lot smarter than good ol' LPT and RS232 ports, which might get in the way of doing this sort of low level stuff.
Does anyone know how a bluetooth device could pick up the discoverable devices' device IDs in range?
I am ideally looking for the simplest solution that involves the smallest implimentation of the bluetooth protocols.
A starting point would be good, I just wish to create a device that can store all the device ids of nearby bluetooth devices with minimal power consumption, preferably just using radio frequencies and not SDP and whatever else.
If you can't help me with this, please can you help me find good reading material for low level bluetooth (step by step) communication. The reading online is so high level that I cant work out what is actually sent, when.
Laalto nailed the answer from the Bluetooth spec/stack POV, but your question implies your looking for a stand-alone Bluetooth device - not just a laptop app scanning surrounding devices.
I can only speak for the BT chips that the company I work for manufactures (Cambridge Silicon Radio - CSR) but our chips can do that pretty much out of the box. Our chips have an on-board Virtual Machine sandbox that allows access to the firmware functions and Bluetooth stack of the chip. You can easily write a C code app to run in the virtual machine sandbox, on chip, that periodically scans for discoverable devices around, grab their ids and then download them when connected via USB or Serial, or maybe over BT when a device connects to the listener directly.
www.csr.com and www.csrsupport.com for chips, dev-kits, design references, etc.. etc...
You probably want a module with the extra HW (UARTs, USB etc...) as well as just the chip but you could implement this with something the size of a BlueTooth USB or probably smaller.
It would really help to know more about what your trying to achieve, why you want something that just scans the surrounding bluetooth devices and how big the device needs to be.
Sorry if this sounds like advertising. For balance: Broadcom make BT chips too!
The Bluetooth specs from http://www.bluetooth.org are a good starting place for low-level information. You need an account to access the specs, but you can create one for free.
Basically what you need to do is to go into Inquiry mode periodically and grab the response packets as they arrive. The more time you spend in Inquiry mode, the more likely you will discover devices in range: discoverable devices enter the Inquiry Scan mode only relatively rarely; it takes some time (10.24s at least with older Bluetooth versions) to scan all the possible frequencies in the Inquiry/Inquiry Scan frequency hopping schemes. And even then you can have suboptimal radio conditions.
For implementation I suggest you at least start with existing Bluetooth libraries such as BlueZ and do not attempt to create your own from scratch.