BLE configuring Signal Strength

[Peter Russell]

Hi,

I am building a device to act as an iBeacon, with other services layered on top. This is based on a Raspberry Pi with a Class 1 USB Bluetooth dongle.

I need to be able to amend the signal strength so as to create a "patchwork" of beacons that will a closely as possible accurately cover an irregular sized region.

I have been using bccmd to try and achieve this, but it is having no effect. I suspect that either the dongles I am trying do not support the bccmd calls, or there is a problem with bccmd on Raspbian, or I am doing something stupid.

These are the commands I am sending:

# PSKEY_LC_MAX_TX_POWER_NO_RSSI
sudo bccmd -d hci0 psset -s 0x0000 0x002d 1
sudo bccmd -d hci0 psget -s 0x0000 0x002d

# PSKEY_LC_DEFAULT_TX_POWER
sudo bccmd -d hci0 psset -s 0x0000 0x0021 -12
sudo bccmd -d hci0 psget -s 0x0000 0x0021

# PSKEY_LC_MAX_TX_POWER
sudo bccmd -d hci0 psset -s 0x0000 0x0017 -12
sudo bccmd -d hci0 psget -s 0x0000 0x0017

echo "Warm Reset..."
sudo bccmd -d hci0 warmreset

Is there a product that anyone can recommend that supports this facility on Raspberry Pi - or can anyone point out what I am doing wrong?

thanks

[ketil]

Hi,

Make sure that you are using a dongle that supports BT 4.1 or later.

I am not familiar with bccmd but according to this page it is made for CSR devices.

If your use case requires a lot of beacons it will quickly get expensive to have every single one attached to a Raspberry Pi. In that case you might want to consider Bluetooth Mesh and having your nodes act as beacons with a single Raspberry Pi Gateway.

Ketil

[Peter Russell]

Hi,

Thanks for your help. I am not particularly wedded to bccmd, is there another approach you would recommend?

I need to have a Raspberry Pi or similar behind the beacon as it is running extra logic in Node.js behind the beacon, cost is not necessarily a major concern, currently.

[ketil]

Hi,

I recommend that you take a look at noble which is a BLE central module for node.js.

Ketil

[Peter Russell]

Hi, I am already using Bleno which is the broadcast counterpart to Noble.What I am looking for is some help with amending the Broadcast power of the actual Bluetooth device similar to how bccmd does (or should do)

[ketil]

Hi,

Do you mean that you want to change the Radio TX power? If you are using one of our devices you would have to make some minor firmware modifications. I can't really provide any help on interfacing with Bluetooth dongles from other companies.

A possible solution would be to use the nRF51 Dongle with pc-ble-driver-js. 

Ketil