hai!!
i am doing my project on bladder pressure measuring system. i have decided to use 150psi-G-4V pressure sensor from "ALL SENSORS" along with PIC16F877 since i need to show the value of pressure in the lcd. also i need to measure the volume of urine coming out when the surgeon applies pressure . so please suggest me the bestvolumetric transducer that can be interfaced with pic along with pressure transducer and the method to interface my pressure transducer with pic ,lcd along with programms. i am using ccs-c compiler and ICD-S programmer.

 

I have not worked with any logic-level volumetric transducers, but I would expect ANY volumetric transducer that is LOGIC LEVEL to work fine with the PIC.

As long as the transducer is rated for the volumes you are expecting, it should work.

 

THANKU RM!!!!!!!
well logic level transducer in the sense??i didnt get it...

 

i have decided to use 150psi-G-4V

150 PSI is a pressure more likely for a steam boiler than one's bladder. The sensor will work, but with a tiny response. You might check similar studies to find the usual pressure found, but it is more likely to be around 3 - 5 PSI.

 

hai thanku 4 suggesting the pressure value.actually i was wrong in calculating the pressure ...200mm of Hg(i.e) ~=5psi-d-4v...thankuu

 

150 PSI... that would be after a heavy...heavy night of drinking and not "breaking the seal" once

 

If I could develop 150PSI of pressure in my bladder, I could write my name in the snow - from Orlando!

 

hey look quick its the "golden" gate bridge..

 

Great yuks you guys, but OP wants to know what "logic level" means.

It means that the transducer has an output in the 0 to 5 volt range, right?

and how would I find that information, he says.

It will be in the description of the sensors you are perusing. Read the descriptions carefully.

 

Bladder pressure kills. Rumor has it that Tyco Brahe, a famous astronomer in the 1500's, died from a burst bladder. Ouch.

If the OP wants a digital display it will likely be some analog components to this device. I'll be interested in the final device chosen.

 

Yow! I had no idea that star gazing was that dangerous!

 

If I could develop 150PSI of pressure in my bladder, I could write my name in the snow - from Orlando!

Sigh it has happened again. A simple question has turned into a peeing contest once more
Well hmm back to topic. I do not have very accurate figures on this topic. But from what I remember. It think it will be in the area of about 20 mmHg in rest conditions for healthy people. But I have to check that numbers

 

hai!!!
i thought of making use of pressure transducer which works on piezoresistive effect... now i was asked to search a transducer based on load cells or strain gauge .could you ploz help me in finding the best loadcell that can be interfaced with a pic and measures pressure in the range of (0-200)mm of Hg.

 

Is this to be connected to a catheter? I hope? And you will need a way to keep one persons 'test' from mixing with the next persons 'test'.

Piezo may not be the best idea. Piezo will report pulsing pressure, not steady. It only creates a signal while being "flexed".

200 millimeters of mercury in 1 mm steps is a little under 8 bits of resolution. Do you think you will require more the 1 mm steps?

 

I think I have found a good product for you to use. It is a catheter-tip bladder transducer.

with a 5µV/V/mmHg sensitivity, you will need an inst amp or such to boost the output to match the PIC.

http://www.gaeltec.com/products2.html#04

and here is there datasheet:
http://www.gaeltec.com/pdf/CTU.pdf

 

Is this to be connected to a catheter? I hope? And you will need a way to keep one persons 'test' from mixing with the next persons 'test'.

Piezo may not be the best idea. Piezo will report pulsing pressure, not steady. It only creates a signal while being "flexed".

200 millimeters of mercury in 1 mm steps is a little under 8 bits of resolution. Do you think you will require more the 1 mm steps?

Common medical pressure sensors is not piezoelectric, but piezoresistive pressure sensors. Such sensors can be made very small and cheap. As they are very often based on silicon, and produced in the same manner as ICs. It is quite common to mix the two terms together.
Most medical pressure sensors are of 5µV/V/mmHg sensitivity. They need an excitation voltage (AC or DC). And they give a differential output. So you will need a instrumentation amplifier. Do NOT try to build one your self, with discrete components. Get a commercial type of high quality.
To get you started I suggest you Google
piezoresistive pressure sensors
instrumentation amplifier
Edit: Try this link also http://ww1.microchip.com/downloads/en/AppNotes/00695a.pdf

 

"Logic level" is generally considered to be low voltage. Standard TTL logic level is <0.8v for a logic zero, and >3v for a logic 1. However, CMOS versions of standard TTL IC's are generally operated on anywhere from 2.5v to 5.5v.

"Logic level" MOSFETs are usually rated for Rds(on) when their Vgs (voltage on the gate referenced from the source terminal) is 4.5v.

If you want code samples, you can find plenty on the Microchip website, and in the MPASM suite, which is a free download.

The PIC16F877 is basically obsolete. Use a PIC16F887 instead.

If you are going to use an LCD with individual segments, use a uC that is designed to drive them, like a PIC16F193x series.