SEN0208 Very less Range and Unstable
surya.Thanush.Intangles 2025-07-01 13:22:48 215 Views1 Replies Hi
We are a Hardware team from India.
We recently got our hands onto the SEN0208 waterproof Ultrasonic sensor bought from Digikey
link : https://www.digikey.in/en/products/detail/dfrobot/SEN0208/6588472
We did preliminary range tests with it.
Below is the test setup and Observations.
Test setup:
Test condition:
- Mode 0: Floating high level (PWM) pulse width output- Mode 1: UART automatic output- Both the modes the sensor measures output up to 2 meter range. Above 2 meter the reading is constant 0.Observations:
- The sensor reading is accuracy is +/- 0.2 m- Reading for the stationary object kept at 1 meter distance varies between 0.8 to 1.2 meter- The sensor reading is not consistent- For the stationary object there are multiple 0 value packets present in the reading
- Up to 0.5 meter range there are ~20% 0 value packets.
- Up to 1 meter range there are ~50% 0 value packets.
- Up to 1.5 meter range there are ~70% 0 value packets.
- Up to 2 meter range there are ~99% 0 value packets.
- Above 2 meter no reading, occasionally reads 1 or 2 packets up to 3 meter range.
We would like to know why the Actual Range is limited to 2 Meters and why the Readings are not so consistent and Reliable and Why Lots of “0cm readings” comes in between as distance increases
Awaiting your Response
Surya Thanush
Intangles Lab Pvt. Ltd.
Ultrasonic reflections depend on surface reflectivity, angle, distance, and ambient noise. The SEN0208 uses narrow pulse and gain, so:
It may fail to detect distant or non-perpendicular objects.
“0” indicates no echo received within the timeout.
Above 1.5 m, you reported >70% zero-packets — likely because the echo signal is too weak or scattered.
ahsrab.rifat 
