You can find the processor chip in the specification section of our beacon descriptions. Most people don’t know what this means or implies. This article will help you make a more informed choice.
There are currently three main chip families from Texas Instruments (CC25xx, CC26xx), Dialog Semiconductor (DAxxxx) and Nordic Semiconductor (nRF51xxx and nRF52xxx). These chip manufacturers publish standard electronic circuits and software SDKs that beacon OEMs use for their beacons. Hence, most beacons, within a chip family, have very similar designs. Small differences in implementation of board layout in areas such as the power supply, grounding, terminations, connectors and the antenna can cause electrical differences that can cause loss of power.
The strength of the beacon radio signal is affected more by the quality of the beacon implementation, particularly the antenna, rather than the choice of chip. This is also evident in real world tests. We have performed RSSI strength and stability tests on the beacons we sell and haven’t yet found any correlation between signal strength and chip family.
The choice of SoC affects battery use. Newer chip families such as the Nordic nRF52 (as opposed to nRF51) and Texas Instruments CC2640 (as opposed to CC2541) are more power efficient.
Most beacon SoCs transmit up to +4dBm output power for a longer range. A few such as the nRF52840 and CC2640RF can be set to higher output power of +8dBm and +5dBM respectively, with a consequent reduction of battery life. If you are looking for longer range, it’s more usual to use a long range beacon with an additional output amplifier chip.
We have a new beacon, the Feasycom FSC-BP103 in stock. It’s a small beacon that transmits up to 10 channels simultaneously that can be Eddystone-UID, Eddystone-URL, iBeacon or AltBeacon.
This beacon uses the newer Texas Instruments CC2640R2F System on a Chip (SoC) that provides a longer battery life. Also, it can be set to advertise at +5dBm that provides a 100m+ range that’s unusual for a small battery beacon.
They studied the radio signal from multiple Texas Instruments SensorTag CC2650 devices in order to determine if it could be used to determine location.
“Given the large number of factors governing the received RSSI, calibration is unlikely to be able to compensate for all of
them, leading us to conclude that there is an inherent limit to the accuracy of a BLE positioning system especially when multiple devices are used.”
…that instead of using a single RSSI measurement to estimate distance, try using the average or median value of N measurements collected on the same spot (at least N>20) so that you can reduce the effect of small scale fading.
The type of System on a Chip (SoC) can greatly affect beacon battery life. At one time it was only Dialog that had low power SoCs. TI, NXP and Nordic followed and now Toshiba has joined them with their new TC35678FSG, TC35678FXG and TC35679FSG (PDF).
We have been looking into the TI CC2640 SoC used in our latest PC062 beacon. The main advantage of the TI CC2640 is exceptional battery life. However, the CC2640 specification provides added features that we expect to be utilised in feature beacons.
The CC2640 has 3 processor cores so that the application (M3 core) and Bluetooth stack (M0 core) can run separately. Previously, they both ran on the same core preventing the beacon from doing additional CPU intensive tasks such as WiFi. The third core (SCE) deals with sensors/peripherals allowing the main core to spend longer time sleeping thus saving power.
Hence, in the near future we expect beacons to become much more capable, for example supporting multiple wireless protocols. IoT sensor beacons will also be able to be produced that will still able to be extra low power despite the extra sensors.