SEN136B5B Ultrasonic Ranger: how to get decent results?


I’ve bought a SEN136B5B Ultrasonic Range Measurement Module. Unfortunately I bought it from a distributor. Had I bought it directly from SeedStudios I would be already sending it back and asking for a refund.

The only thing it seems to detect with reasonable reliability within the range given in the specifications (400 cm!!!) seems to be A WALL.

For objects like chairs and PERSONS, it is almost acceptably reliable only below 40 cm, meaning that an adult standing right in front of the sensor at a distance above 40cm (the sensor being at the height of the belly) will be detected only half of the time. At distances greater than 80cm-1m a person will always never be detected. To have it detected and ranged most of the time (i.e. reliably) it must be within about 20cm. This is about 1/10 - 1/20 of the range in the specifications.

I guess the trick is in the fact the specifications don’t say how big an object needs to be to be detected at 400cm.

So, my question is, if it is not suitable for detecting something like a person, what exactly is it designed or supposed to be used for? Detecting MOVING WALLS? Whales? Trucks?

I am curious to hear experiences of anybody SUCCESFULLY using this sensor, and what they used it for.

Or what would be the conditions necessary to obtain decent results at reasonable distances for detecting people? (by reasonable distances I mean at least a couple of meters)

By the way I tried this other sensor: and it works way, way better. (A person standing in front of the sensor is ranged with almost perfect reliability within about 2m, and I haven’t tried more)


Sorry about the Ultrasonic Ranger can not work right and inconvenience to you. When I see your post , I go to our warehouse took the same Ulltrasonic Ranger ,download the code on the wiki and runing it . And I tested it several times , whether 40 cm or 40 cm above , it work very well really. Maybe your Ultrasonic Ranger work for a long time , and it have a little fault . For this question , apologize again . And I will react it to product testing department .

best regards,

I have two of them, one brand-new and the other I bought very few months ago and used very little, and I have experienced the same problems with both. I have tested the code downloaded from your page just to make sure (my code is based on the same code and is basically identical) and I get the same results.

Could you please describe your succesful testing scenario, your physical setup, where you place the sensor, e.g. what height above ground, how you orient it etc, so that I may try to see which conditions in my tests (if any) are preventing the sensor from working correctly? Are there any factors that are especially likely to degrade performance which I should avoid?

I’m using the sensor at approx human-belly height above the ground, facing in a direction parallel to the ground, with its back part fixed to a wall or piece of forniture, so it is steady, and I’m trying to range a person in front of it.

Is it necessary to have a very clean and flat background? When the obstacle (i.e. the person) is not present, the ranging of the background (i.e. maximum distance value) is correct, so the irregular background doesn’t seem to be the problem.

I’ve also tried this other setup: sensor laid down with its back on the table, facing upwards; no obstacle between it and the ceiling (flat clean white ceiling). Then I put a hand above it which I try to range. Ranging of the hand is reliable and correct below about 30cm, then already becomes very unreliable or stops detecting it completely.

Thank you

I put it on my table about to my thigh level , then I move back and forward more than two meters above the distance .I was very tiny , not a very strong person . My test is no problem , make sure the Ultrasonic Ranger I used can work right .
Others , if some of the materials that the ultrasonic reflected the spread of influence ?Perhaps it is our product quality problems …but i cann’t come to a conclusion.
I had reacted it to product testing department .I think the biggest problem is anything I can help you ?