Iam participating in SMART METER design wBluetooth connectivity nowdays which we think it will be of use in areas with little infrastructure support,so data can be gathered manually by a Bluetooth reader around the residental block users.Any suggestion about the subject or sugestions for further readings ,sources?
What is best protocol for system with low power (battery powered devices), low cost, easy to implement, short range (approx 1/2 mile radius), data only (no voice needed), small data transmissions (approx 1-2 kbyte),
I'm a retired electro-mechanical designer. A novice in electronics and programming. Working independently on a commercial product.
in the near field, with any radio technology, we need to worry about over-driving the receiver. Typically, 1 food gives you sufficient distance as far as over-driving goes. Near field coupling is OK for communications.
I am not aware of BT applications opperating over 100 meters, but there may be factory networks that require synchronous operation that BT delivers and where BT nodes have sufficient power. I believe there may be some apps like that in the future.
Antenna should be at least a quarter wavelength of the frequency. The wavelength of 13 MHz is about 30 meters. Antennas shorter than that will result in signal power loss. NFC antennas are typically printed on a PCB in a spiral fashion. The range of NFC is very short, so lower than 1/4 wave is ok for NFC.
for printed antennas, it may be obvious, but avoid metal surfaces inside and metal enclosure. batteries, ground planes, power supplies can all seriously impact the printed (or any internal antenna) performance. We will touch on this in the next session.
Thanks Fanny for your lecture. I have two questions: 1. will wifi and BT interfere with each other as they both operate in the 2.4GHz frequency band? 2. How long does it take for BT to establish connection
BT started with devices that supported their Profiles.The issue with Devices and accessories are the compatibility of the Profiles and their different Versions. Is there any improvements in simplifying the Profile structure in BT SIG ?
Vocera uses Bluetooth in conjunction with VoWLAN, so have an "interesting" situation re. the typically shared/switched aspect of BT RF within a chipset/radio module. LE is interesting (given battery life concerns), but likely more suitable for sensor vs. voice/QoS. DoD frowns on BT 3.0, and interested in the forward/backwards RF compatabilityaspects of BT 4.0 vs. earlier: channelization changing, more Wi-Fi co-ex "friendly"
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