Help for a pressure sensor application

Discussion in 'The Projects Forum' started by yaantey, Oct 26, 2011.

  1. yaantey

    Thread Starter Member

    Oct 7, 2011
    I want to make a simple weighing machine to weigh objects weighing max 30 kg and output on a display. As for accuracy, a +/- 1 kg can be acceptable. I have done some googling and found out some ways to implement this. What I have found are:

    • FSR
    • Load Cells
    • Piezoresistive Force Sensor
    So, what I want to know is that is there any other way I can implement this which is more efficient, simple, accurate and cheap. Also is there a sensor that I can simply buy, program and interface with microcontroller.

    Im very new to electronics and this is just the second project I am doing. So, I am just learning everyday. Any genuine help is greatly appreciated.
  2. chrisw1990

    Active Member

    Oct 22, 2011
    what kind of weighing? like a desk weigher? or hanging?
  3. someonesdad

    Senior Member

    Jul 7, 2009
    If you can measure in a pan or on a suspended platform, consider making a simple device like a balance (this can also be done with a platform-type scale, but it's a little more complex mechanically). The other end would e.g. pull on a pot with a linear adjustment (or wrap a string around a disk that turns a rotary pot); a spring would cause it to return to zero. This could easily be made to meet your accuracy of ±1 in 30 -- and it can be simple and rugged. Then the next step is to answer how to get the reading into your computer. There are lots of choices here (and this is where you'll spend the money, as the measuring part of it could probably be built from scrap). Me, I'd go with a GPIB voltmeter, as I have one already hooked up. But I'm going to guess that you'll want to get some kind of USB analog input module. If you have a serial port for your computer, you could use a microcontroller to digitize the pot reading and send it to the PC via the serial port. But this will require learning some uC programming (but the part itself should only cost a few bucks).