Hello guys,
I am using this module jsn-sr04t, and getting the proper output upto 3 meters. Pulse width decreases when object come near to sensor.... Upto this is OK.
But the main problem associated with this is, proper output is from 300mm. If object coming more close to it(Distance less than 300 mm) then instead of of decreasing the pulse width, it is increasing which creates the problem in my application.....
Do you also getting the same problem........If yes then there is no meaning in using this module......
It sounds like you've either got a faulty device, or you're not measuring what you think you are.
Without further details, it's almost impossible to say.
Is it a waterproofed srf-04? then it might blank-out lower cm readings, that means it has a minimum ~25 cm range.
Read this carefully http://inside.mines.edu/~whoff/courses/EENG383/lab/SRF04%20Technical%20Documentation.pdf
I am back with the pulses......
Module which i am using is this. http://www.icstation.com/ultrasonic-module-sr04t-distance-measuring-transducer-sensor-p-5046.html
in it's specification it is clearly given that the blind area is 25cm(250mm).............(what they mean by blind area????????)
The pulses i observed is given.......
- Sensor is 800mm from object- module giving proper pulses-(OK)
- Sensor is 500mm from object- Ton Pulse width decreased-(OK)
- Sensor is 350mm from object- Ton Pulse width decreased further-(OK)
- Sensor is 100mm from object- Ton Pulse width changes randomly-(NOT OK)
- Sensor is 40mm from object- Ton Pulse width increased-(NOT OK)
I couldn't find any official technical support email id where i can ask my question. Does any one knows it?
Really Comfused.... 
I gave you advice to read a document. You apparently did not, since it explains what blind area is, why it is and how to fix it.
this issue was already discussed https://forum.arduino.cc/index.php?topic=339184.15
Thanx blimpyway for this forum link......
The thing which i can get from this discussion is taking 10 reading, averaging it and comparing with all....Ok that will work only when pulses getting are random width................
Ok i will try it in my code................
What you think if i replace the HC-SR04 two sensors with my waterproof two sensors?......... Will have to try........
I don't know what your application for the sensor is, so I cant help too much. From the older forum thread I get it the max improvement they got was reduce the blind area from 25 down to 19cm or so.. not much, with longer readings to compute an average.
I bought the latest version 2.0 for JSN SR04T and had many problems with it. It is not stable.
As per this video, others are also having the same problem.
And JSN SR04T has a blind/minimum distance of around 20cm because it has only 1 transducer and that is another problem apart from not being stable.
I was searching and searching for solutions and found this sensor
It has 2 transducers instead of 1 and therefore has minimum distance of around 3cm and it is completely sealed from all sides making it fully waterproof and is working very nicely for my tank level project.