Bit:Bot soldered Ultra Sonic sensor 4-tronix

Ready-Soldered, just attach to your Bit:Bot Classic with the screws provided and off you go.
Use Microsoft Makecode or MicroPython to read the distance to an obstacle, then program your Bit:Bot to avoid it.

Both Ping and Echo signals are on the same pin (Pin 15)

This accessory is now only available in 1 flavour: With the ultrasonic sensor soldered directly to the PCB

The sensor soldered into the PCB is much more robust and reliable, but has a drawback in that you cannot access the micro-USB connector on the micro:bit unless you either remove the micro:bit or use a right-angled USB cable.