need cheap pressure sensor
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From: qrk on 22 May 2010 12:40 On Thu, 20 May 2010 20:28:47 -0700 (PDT), "lektric.dan(a)gmail.com" <lektric.dan(a)gmail.com> wrote: >I'm working on a project to help develop a solar powered water pump. >The pump is called a fluidyne, essentially a liquid piston Sterling >engine. You can find more about the project here: >http://www.iedu.com/DeSoto/Fluidyne/ >What I would like to do is build a small fluidyne that I can put a >specific, controlled amount of heat into, and measure the results. >I'd like to find a source for (very) inexpensive pressure sunsors. >They need to be able to measure very small pressures (50 cm water >pressure). I've got all kinds of interface circuitry, so I can >measure a sensor that uses a strain gauge (in whatever configuration), >simple resistance changes, piezoelectric, or whatever. Any ideas or >sources? http://www.keller-druck.com/english/homee/hmprode.html These are around $20. You'll need to calibrate it.
From: lektric.dan on 22 May 2010 17:22 On May 21, 7:26 pm, mpm <mpmill...(a)aol.com> wrote: > Do you need to measure pressure, or just need a switch function at a > given pressure (+/-)? I'm trying to charactorize how the pumps function. In other words: build one to a set of dimensions. Apply a controlled heat/ temperature. Record pressurs and pumping volume. Record all this. Change temperature, repeat. Now build new pump with different dimensions. Repeat above. Analyze and try to create algorythm(s) that describe how physical dimensions and energu applied affect pump mechanics.
From: lektric.dan on 22 May 2010 17:25 On May 21, 10:36 pm, whit3rd <whit...(a)gmail.com> wrote: > On May 20, 8:28 pm, "lektric....(a)gmail.com" <lektric....(a)gmail.com> > wrote: > > > I'm working on a project to help develop a solar powered water pump. > > I'd like to find a source for (very) inexpensive pressure sunsors. > > They need to be able to measure very small pressures (50 cm water > > pressure). I've got all kinds of interface circuitry... > > And, it all has to fit down a well? > The PUMP will eventually fit down a well. I need to see how one works "up here" when made at different sizes and shapes, and different amounts of heat are applied.
From: lektric.dan on 23 May 2010 03:43 On May 21, 9:22 pm, Ecnerwal <MyNameForw...(a)ReplaceWithMyVices.Com.invalid> wrote: > Mouser and newark have various sensors that look like they would work > for $5 to $11 (as well as other ones that run into the hundred$) so it > depends what you mean by (very), and whether availability without > dicking around with surplus is worth anything to you. Mouser is better > at the low end of that price range. I was hoping to find something less than $5. I've found what I think will work for about $8. I need less than 10 so I won't be out too terribly much. Self-funding research requires dedication, I'm finding. > > Agony at a very low cost is available by using a manometer tube and a > bunch of optical sensors that switch when there's water rather than air > in the tube - though by the time you get enough of them on there for > resolution, it might not be so cheap after all. Years ago I was working on a project involving digitizing human motion. We needed to record a synchronized low pressure signal along side the video. We ended up making a manometer out of a jar and a glass tube. Height of liquid (red dyed water) gave pressure. Video analysis software converted pixels into inches and actually plotted the data for us along side motion data.
From: hamilton on 23 May 2010 10:22
On 5/23/2010 1:43 AM, lektric.dan(a)gmail.com wrote: > > I was hoping to find something less than $5. I've found what I think > will work for about $8. I need less than 10 so I won't be out too What did you find for less the $8 ?? hamilton |