# Sentinel Drone Rangefinder

Source: https://forum.modalai.com/topic/3129/sentinel-drone-rangefinder
Category: Development Drones (https://forum.modalai.com/category/44/development-drones)
Tags: sentinel
Posted: 2024-02-19 03:13:13 UTC by Erik Priest
Replies: 1 · Views: 777

## Erik Priest · 2024-02-19 03:13:13 UTC

I was wondering where the two range finders are installed on the sentinel drone. From the [documentation](https://docs.modalai.com/sentinel-functional-description/#processing-specs) there should be 2 TDK CH-201 ultrasonic rangefinder sensors on the drone however, I couldn't find anymore information on where to read this data or their locations with respect to the drone. Are they indeed used on the drone or is this a miscommunication?

## Reply by Chad Sweet (ModalAI staff) · 2024-02-19 06:04:38 UTC

Hi Erik, thanks for pointing that out. It was a mistake, it has now been fixed as there are no CH-201 sensors