@zboblamont said in 1.2 MPa pressure transducer:
In industry we used to use them atop valves to not only permit servicing but an air pocket acted as a buffer.
Thanks, i'll try the pipe / buffer method and see if that helps. Will use a PVC pipe to rule out any EMC reaching the sensor.
Hi, another strange problem - the ok unit works fine on the workbench, however, when i connect it to the water pipe the readings start fluctuating quite a bit ? Any pointers on how i can stabilise the system ?
@zboblamont said in 1.2 MPa pressure transducer:
@sundeep-goel Short of flushing out the pressure port to dislodge any debris, these are not designed to be repaired...
Thought as much, tried heating it today just in case that helped. No luck, its stuck at VCC now 
real pity, it was almost brand new !!!
@boozz said in 1.2 MPa pressure transducer:
Maybe something like this?
This comes from: https://issuu.com/process1/docs/pii-june-2019
Page 14 and further
Super, thanks!!
Any idea on what (if anything) could be done to get it working properly again ?
Hi,
Can someone point me towards some documentation which explain the working (i mean internal working) of the 1904 / 1.2 MPa pressure transducer.
I have two units, one of which has started behaving erratically with readings fluctuating wildly from 300mv to Vcc.
regards,
Sundeep
@zboblamont said in Trouble with the JSN SR04T:
what the range is that version, I've seen 1m and 2m quoted for the same model number..?
I have tested till around 2meters succesfully. I read somewhere that you can also switch to another mode to increase range, haven't tried that though.
Let me know if you need more information, as of now I have added only one sensor, will be adding one more next week, so can run more tests then
@sundeep-goel said in Trouble with the JSN SR04T:
will install in the tank tomorrow morning, fingers crossed
Installed under a tank nipple (needed to attach to lower end, was getting issues at the end)
getting steady readings now
in brief, too many issues with the JSN SR04T sensor in my tank, Laser TOF Sensor VL53L0X is better and cheaper in given setup.
@sundeep-goel said in Trouble with the JSN SR04T:
putting this sensor aside and switching to the IR laser sensor VL53L0X.
replaced JSN SR04T with VL53L0X
So far the tests in a experimental setup (i.e. using a mug of water as a reflective surface are good), will install in the tank tomorrow morning, fingers crossed.
@zboblamont said in Trouble with the JSN SR04T:
The sensor is working perfect outside the tank - tested both with 10us and 15us. Also, same with / without a voltage divider.
Saw a possible issue in the code
Ultrasonic ultrasonic1(4, 13); // An ultrasonic sensor HC-04
Ultrasonic ultrasonic2(4, 12); // An ultrasonic sensor HC-04
Was using same trigger pins on the esp for both sensor, ideally this should not have been creating a problem. but just to be sure, tried with only one sensor - worked fine outside the tank
Inside the tank in all cases, back to square one i.e. readings between 20-25cm only.
For now , putting this sensor aside and switching to the IR laser sensor VL53L0X. Lets see how that does, will post back the results soon
@zboblamont said in Trouble with the JSN SR04T:
hang the sensor through the hatch and to see if it works reliably there
Got you, will try this and a couple of others. Will post back the results.
On a related topic, is this sensor good sensing water level [link text](GY-VL53L0XV2 Laser Distance Module I2C IIC 3.3V/5V
https://s.click.aliexpress.com/e/73Fe2bm)
@zboblamont said in Trouble with the JSN SR04T:
but your sensor would be better centralised
I thought about this, however, our tanks have a typical float ball which will mess up the reflections from the center. This was one of the major reasons for putting the sensor off-center and also inside a standtube.
![0_1563969848049_ball-float-valve-500x500.jpg]
(/assets/uploads/files/1563969850870-ball-float-valve-500x500.jpg)
@zboblamont said in Trouble with the JSN SR04T:
I suggest a 90 degree under your current entry, a short extension to the centre, then down to just above 200mm from top water level
Can you please elaborate on this? do you mean something like?
if yes, wont there be reflections from the elbow ?
@zboblamont said in Trouble with the JSN SR04T:
Can you confirm the JSN model number does not have 2.0
the board does not have a number on it. The link to the item is : link text. Seem to be a non 2.0 version. However, since the unit is getting trigged, and also detecting echos - can the operating voltage still be an issue ?
@zboblamont said in Trouble with the JSN SR04T:
From what I read the 15 microsecond is important.
I'll try with 15 us, changing the library is not a big deal.
I'll also try adding a voltage divider across the ECHO output into the GPIO pin to see if that makes a differnce.
@zboblamont said in Trouble with the JSN SR04T:
Can we please establish a baseline of what you are using and the physical parameters, a fresh pair of eyes is only useful if the blinds are removed
I agree, let me try and address all the queries.
digitalWrite(trig, LOW);
delayMicroseconds(2);
digitalWrite(trig, HIGH);
delayMicroseconds(10);
digitalWrite(trig, LOW);
Tank - total height say 130cm
Mounting Hole - its offset from the side by 25cms
Inside of the tank
JSN 04T driver module
Sensor head mounted inside standpipes
@zboblamont said in Trouble with the JSN SR04T:
is the pulse set for 15 microseconds
How do I check for this? Am using the ultrasonic Arduino library
@zboblamont said in Trouble with the JSN SR04T:
Not quite clear what casing you removed from the ultrasonic, the waterproof button should fit directly into a 20mm socket, and the cable runs up the tube.
Needed to remove the plastic to fit sensor inside a standpipe 1.5cm diameter (baffle) to reduce reflecting from side of the tank (which i assumed was causing most of the issues.
Note : If i insert the sensor face more than 1.2cm away from the pipe edge, keep getting 20cm readings only. Same happening if i go for a pipe with a larger diameter.
Even after this, i keep getting erratic readings
The left one is not as erratic - but innaccurate , the right one is completely bonkers 
Hi,
I am having some trouble with the JSN SR04T - I am using it to measure the water level in a overhead tank. However, the readings keep varying between 20-30cm only. I assumed this was because of the wide beam spread / echo, so tried to build a stand pipe using design from https://blog.lesman.com/2014/04/29/does-ultrasonic-level-measurement-work-with-a-standpipe/.
However, this did not work out, key issue which i ran into was that the diameter to height ratio of beyond 1:1 is not working out, kept getting same erronious readings when i increased the height of the sensor in the pipe. With a bit of experimentation, worked out that a height of 1.2cm is the max you can go for inside 2cm inner diameter pipe.
With this setup i.e taking the transducer out of its plastic casing, inserting it inside a 2cm tank nipple, keeping the sensor face at height of 1.2 from end, getting readings which are better but still not fully accurate.
Please suggest