A Bluetooth module that can work over a distance of 1km has been developed by Buckinghamshire-based Ezurio.

“I like to think that we haven’t made any compromises,” said Nick Hunn, chief technology officer at Ezurio. “It took quite a lot of time to get it to that point and performance. It’s all there approved and legal.”

The firm’s postage stamp-sized BISM2PA Bluetooth module is pin and footprint compatible with its existing range. It uses an omni-directional antenna and includes a matched and optimised RF power amplifier which boosts the transmit power to +18dBm and a low noise amplifier at the receiver input enhances the receive sensitivity.

Hunn said the long range on the module, which is based around a CSR chip, was achieved using “really good RF engineering practice”.

“It’s changing the details throughout to make sure everything you’re trying to do on the radio gets to the antennas and gets out rather than being bounced around and lost,” said Hunn. “Equally there was a lot of attention to the receive chain - matching amplifiers - so we can listen as attentively as possible to what is happening out there in the world. It’s not just being able to shout loudly, but also being able to listen more effectively.”

Hunn said the module was designed following requests from customers but said, “not a lot of people want to use them 1km apart”. The module’s long range means the signal is very robust indoors. “It gives plenty of overhead so you can be sure when you make something and deploy it that it’ll work,” said Hunn.