Bluetooth Demystified

BTDM, BLE, Bluetooth Classic, WiFi—with so many sensor technologies out there, how do we know the best one to use when gathering data for arterial performance measures? Here is a breakdown of the differences, and which one has been the data collection powerhouse for us.

Bluetooth Classes

Heard of Bluetooth described as Class 1, Class 2, and Class 3? This classification system was put in place to categorize Bluetooth devices as long range (Class 1), medium range (Class 2), and short range (Class 3). Bluetooth Classes apply to both Bluetooth Classic and Bluetooth Low Energy.

Bluetooth Classic

You’ve probably used this technology on your wireless headphones, keyboard, or car stereo system. Specifications for this wireless sensor technology that you know and love was formalized by the Bluetooth Special Interest Group (SIG) in May 1998. It was developed and optimized for continuous data streaming and is included in every Bluetooth Core Specification since its inception.

At Bluemac, we colloquially refer to these traditional forms of Bluetooth sensors as Bluetooth Classic.

Bluetooth Low Energy (BLE)

Every development since Bluetooth 4.0 has been an advancement in the capabilities of Bluetooth Low Energy (BLE), which is the Bluetooth of today’s world. Consumer devices such as laptops and smartphones will have both BLE and Bluetooth Classic, but modern headphones and headsets are built with just BLE.

BLE operates in the same 2.4 GHz ISM (industrial, scientific, and medical) band as Bluetooth Classic, but it consumes less power because it operates in sleep mode except when a connection is initiated.


WiFi is another form of wireless communication. As a user, the term WiFi has become almost synonymous with “the Internet.” Since WiFi is typically used for static access points (or hotspots), the Bluemac team has typically seen lower traffic data collection rates with WiFi.

Comparing the Capture Radii

When we put BLE, Bluetooth Classic, and WiFi side by side in the context of data collection, we see significant differences. These are the approximate capture radii in real-world conditions for Bluemac x7, our wireless sensor data collection device used for arterial performance measures and multimodal studies:

  • BLE: approx. 200 feet
  • Bluetooth Classic: approx. 500 feet
  • WiFi: approx. 750 feet

Which is Best?

The triple sensor technology of the Bluemac x7 combines Bluetooth Classic, BLE and Wi-Fi, but when we separate out the data, we see that BLE is the powerhouse and the difference maker.

BLE has the smallest capture radius, which means more accurate travel times, and the minimal overlap allows for denser deployments. BLE technology is also more present out on the street: it is what is used in modern technology, and it works because the majority of BLE devices are always broadcasting.

We typically see seven times more captures during the commuter house from BLE than we do from traditional Bluetooth, and a 30% capture rate of whatever is on the street. This difference can be even greater when looked over a 24-hour period.

An internal study was conducted in Washington County, OR along NW Evergreen Road. More probes were captured using a Bluetooth Low Energy sensor compared to Bluetooth Classic and WiFi. The capture rates shown are approximate using a 24-hour directional traffic counter. Results may vary by site.

What About BTDM?

Normally, Bluetooth signals are modulated so as to remain semi-private. We can tell something is there, but only the source and destination know what it is. Bluetooth demodulator (BTDM) takes non-discoverable data and still scans for MAC addresses to capture more Bluetooth Classic probes.

By capturing non-discoverables, does BTDM outshine BLE? The answer is no:

1) BLE can capture more data than BTDM. BLE generally outperforms BTDM without needing to detect un-discoverable devices.

2) BTDM infringes on user privacy. Users set devices to non-discoverable for a reason. Data you can trust is data that follows the rules and doesn’t flirt with privacy concerns.


Want to talk further about Bluetooth Classic, BLE, Wi-Fi, and BTDM? We speak data! Feel free to contact the team at Bluemac and let’s continue the conversation.