The SpacerLabs "Cyclometer" is a cycle 'trip-computer' which provides a cyclist 🚴 with data on number of wheel revolutions (Revs), distance travelled (Kms), average speed (Av.Kph) and current speed (Kph). It comprises a display unit, magnetic switch and magnet. 3-D printed enclosures for these separate parts give the Cyclometer a smart appearance. The Cyclometer is powered by an internal 3.7V rechargeable Li-Ion polymer battery.
Cycle wheel revolutions are detected by the magnetic switch which is closed and opened by the magnet fixed to a wheel spoke as it passes by close to the switch. The switch is wired to the display unit which counts and displays the revolutions. The distance travelled is calculated from the number of wheel revolutions and the wheel outer circumference measurement. A free-running internal milli-second timer allows the cycle speed to be determined.
 |
| The Cyclometer display unit |
The Cyclometer display unit is unusual as it also acts as a BluetoothⓇ server ( SPACERLABS_CS ) using the 'Bluetooth Low Energy' ( BLE ) variant of BluetoothⓇ. Connecting to it with a paired BluetoothⓇ client device ( e.g., a smart phone 📱), having a suitable App installed enables the Cyclometer ready for use. The BLE features of the Cyclometer have been modelled on the standard service and characteristics of the BluetoothⓇ "Cycling Speed & Cadence Service", though no cadence, ( crank ), data are required by the current version of the Cyclometer. An additional characteristic has been provided to support the wheel outer circumference measurement.
 |
| The SpacerLabs 'Cyclometer' App |
Many general purpose BLE client App's are available. However, here at SpacerLabs, we have built our own custom 'Cyclometer' App for Android devices to make the process of updating sensor location and wheel size quick and easy !
