STRAIN

As part of an onging study, I need a multi-channel instrument for measuring strain that can inteface with a PC.

Off the shelf units are v. expensive so I thought I would make one [multiplexor/signal conditioner/RS232]. To my surprise, having looked everywhere over many months, I can't find any suitably explicit circuits.

There are a few circuits for single gauges but nothing for multi-channel set ups and nothing that includes a PC connection.

Any suggestions/help would be appreciated.

Thanks

Never seen one at a price an individual can stand. Most seem to be custom made.

The cost of load cells - ouch - and resistive strain guages - as in bathroom scales - make it prohibitive. That is without designing and building circuitry to give meaningful output.

If I see anything on my travels I will post the info but until then - Good Luck

I described this on another post a few weeks ago. I purchased data aquisition box from Dataq a month or so ago - $24. It has 4 analog inputs and 2 digital inputs. Sampling rate isn't particularly high. Analog inputs require 10 volts so you have to adapt your sensors to that. The box comes with software. It appears to be something that is sold at low cost and a way of introducing potential users to the basics. The box connects via cable supplied, to the serial port.

Thanks for the replies.

Strain gauge

Vishay's (a.k.a Measurement Group) resistive strain guages are dirt cheap, of course the trick is to install it correctly, the sell starter packs with wire bonds and silicon

www.measurementsgroup.com/guide/guide.htm

This coupled with a cheap but a good instrumentation amplifier like INA126 or INA122 (Burr-Brown/Texas Instruments) and a MCU can make a wonderful strain monitor.

God luck
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