Post by thread:[EE] Brake fluid pressure transducer

I'm looking for a brake fluid pressure transducer to put in my car for data logging. The ones made for that purpose seem to be in the $150 range. Pressure transducers are not something I am looking at on a daily basis so I don't know what the going rate for off-the-shelf industrial models are, or where to buy them in single quantities. Basically brake fluid is fairly benign and the pressure is 0 to 1500 PSI and accuracy is not that important. And I don't care what the input/output is, raw bridge, ratiometric, digital, whatever. Anyone been down this road before and can point me in the right direction? Thanks, Bob -- http://www.fastmail.fm - The professional email service

You don't say anything about pressure range, but, I would think 1000 PSI. would not be enough, probably 2000 psi. might be. The tubing needs to be steel or stainless, and for various reasons including vibration fatigue, copper is a no/no. Might think a bit about a foot can exert say 200 lbs. force x leverage of the brake pedal linkage (measure a couple of cars and trucks (we are thinking hydraulic brakes and not air) x area of the master cylinder piston. Are we thinking production with many pieces, or one or a few pieces. Some vehicle anti lock may have pressure transducers. On 7/1/2010 8:05 PM, Bob Blick wrote: {Quote hidden}> I'm looking for a brake fluid pressure transducer to put in my car for > data logging. > > The ones made for that purpose seem to be in the $150 range. > > Pressure transducers are not something I am looking at on a daily basis > so I don't know what the going rate for off-the-shelf industrial models > are, or where to buy them in single quantities. > > Basically brake fluid is fairly benign and the pressure is 0 to 1500 PSI > and accuracy is not that important. And I don't care what the > input/output is, raw bridge, ratiometric, digital, whatever. > > Anyone been down this road before and can point me in the right > direction? > > Thanks, > > Bob > >

On Thu, 01 Jul 2010 20:57:38 -0400, "Carl Denk" said: > You don't say anything about pressure range, > On 7/1/2010 8:05 PM, Bob Blick wrote: > > > Basically brake fluid is fairly benign and the pressure is 0 to 1500 PSI :) I'm actually pretty familiar with performance brake parts and safety in race cars, so the plumbing part isn't the problem, I just need a sensor. Sensors in ABS systems are integrated into other parts so they aren't applicable. I am looking for a <$100 off-the-shelf industrial sensor or one specifically for automobiles that has a datasheet. So far the least expensive one I have seen is $105 and doesn't come with a datasheet: http://www.pegasusautoracing.com/productdetails.asp?RecId=2907 Thanks for your input. Cheerful regards, Bob -- http://www.fastmail.fm - Access your email from home and the web

Bob, If MSP3252P2-ND at Digikey works for you, contact me offlist as I should be able to get you a better price. BTW, I would be cautious about calling brake fluid "benign". Drop some on the paint of a car you don't like, and you'll see what I mean. Cheers, -Neil. Quoting Bob Blick <spam_OUTbobblickTakeThisOuTftml.net>: {Quote hidden}> I'm looking for a brake fluid pressure transducer to put in my car for > data logging. > > The ones made for that purpose seem to be in the $150 range. > > Pressure transducers are not something I am looking at on a daily basis > so I don't know what the going rate for off-the-shelf industrial models > are, or where to buy them in single quantities. > > Basically brake fluid is fairly benign and the pressure is 0 to 1500 PSI > and accuracy is not that important. And I don't care what the > input/output is, raw bridge, ratiometric, digital, whatever. > > Anyone been down this road before and can point me in the right > direction? > > Thanks, > > Bob > > -- > http://www.fastmail.fm - The professional email service > > -

At 10:13 PM 7/1/2010, you wrote: {Quote hidden}>On Thu, 01 Jul 2010 20:57:38 -0400, "Carl Denk" said: > > You don't say anything about pressure range, > > > On 7/1/2010 8:05 PM, Bob Blick wrote: > > > > > Basically brake fluid is fairly benign and the pressure is 0 to 1500 PSI > >:) > >I'm actually pretty familiar with performance brake parts and safety in >race cars, so the plumbing part isn't the problem, I just need a sensor. > >Sensors in ABS systems are integrated into other parts so they aren't >applicable. I am looking for a <$100 off-the-shelf industrial sensor or >one specifically for automobiles that has a datasheet. > >So far the least expensive one I have seen is $105 and doesn't come with >a datasheet: > >http://www.pegasusautoracing.com/productdetails.asp?RecId=2907 > >Thanks for your input. > >Cheerful regards, > >Bob http://www.antonsre.com.au/index_files/pdf/Datasheet_brakeprs_eng_101.pdf This one looks pretty good: http://sensing.honeywell.com/index.cfm?ci_id=140301&la_id=1&pr_id=122165 $88 in 10's from Mouser, 17 in stock. >Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" .....speffKILLspam@spam@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

On Fri, 02 Jul 2010 09:53:55 -0700, "Brooke Clarke" said: > Have you looked into whether or not that's one of the parameters covered > by OBDC? > If it is then there's already a sensor connected to the brake system. OBD2 doesn't have ABS as part of the standard set of data, it's proprietary. Also I don't have ABS in the car I want to monitor. Completing a little hobby project is always a challenge for me. Feature creep can easily turn that simple little project into something that never gets finished. So I am sticking to 3-axis acceleration, RPM, throttle position, and brake pressure. Anything more is too much to graph all together and besides, these are the important ones. I'm not a Formula One driver, either :) Thanks for everyone's input, I'm sure you'll be hearing more assuming I make progress. This will be my first thing built with an Arduino besides experimental tinkering, unless I decide I hate it and switch to a PIC. So far I like how popular the Arduino is but other than that I don't much care for it. Best regards, Bob -- http://www.fastmail.fm - IMAP accessible web-mail

{Quote hidden}> > On Jul 1, 2010, at 6:05 PM, Bob Blick wrote: > > I'm looking for a brake fluid pressure transducer to put in my car for > data logging. > > The ones made for that purpose seem to be in the $150 range. > > Pressure transducers are not something I am looking at on a daily > basis > so I don't know what the going rate for off-the-shelf industrial > models > are, or where to buy them in single quantities. > > Basically brake fluid is fairly benign and the pressure is 0 to 1500 > PSI > and accuracy is not that important. And I don't care what the > input/output is, raw bridge, ratiometric, digital, whatever. > > Anyone been down this road before and can point me in the right > direction? > > Thanks, > > Bob > Is there a company that makes a fluid isolator/pressure multiplier ? Maybe something mechanical that has a 10:1 ( as an example ) surface ratio change so that 2000 psi on one side is 200 psi on the other ? Gus

Em 2/7/2010 16:44, YES NOPE9 escreveu: {Quote hidden}>> On Jul 1, 2010, at 6:05 PM, Bob Blick wrote: >> >> I'm looking for a brake fluid pressure transducer to put in my car for >> data logging. >> >> The ones made for that purpose seem to be in the $150 range. >> >> Pressure transducers are not something I am looking at on a daily >> basis >> so I don't know what the going rate for off-the-shelf industrial >> models >> are, or where to buy them in single quantities. >> >> Basically brake fluid is fairly benign and the pressure is 0 to 1500 >> PSI >> and accuracy is not that important. And I don't care what the >> input/output is, raw bridge, ratiometric, digital, whatever. >> >> Anyone been down this road before and can point me in the right >> direction? >> >> Thanks, >> >> Bob >> > > Is there a company that makes a fluid isolator/pressure multiplier ? > Maybe something mechanical that has a 10:1 ( as an example ) surface > ratio change so that 2000 psi on one side is 200 psi on the other ? > Gus A good machinist with a lathe and a grinder can make such device. A plunger inside a cylinder with an internal step (the plunger stepped also), the cross section of the bigger diameter portion with an area ten times that of the smaller diameter portion. High pressure applied to the smaller diameter end pushes the plunger, the pressure at the larger diameter end is 1/10 of the pressure at the smaller diameter end. The tricky part is the leakage, perhaps some O-Rings near each end with a hole through the cylinder wall, between the sections to drain any fluid that may leak from either side. The pressure reduction may be even higher, perhaps hundreds of times, to suit any pressure sensor you may find. A better option would be a device like this one but instead of using pressure at the larger diameter end, just attach a strain-gauge and read the pressure by means of the strain. Isaac __________________________________________________ Fale com seus amigos de graça com o novo Yahoo! Messenger http://br.messenger.yahoo.com/

Isaac Marino Bavaresco wrote: {Quote hidden}> Em 2/7/2010 16:44, YES NOPE9 escreveu: > >>> On Jul 1, 2010, at 6:05 PM, Bob Blick wrote: >>> >>> I'm looking for a brake fluid pressure transducer to put in my car for >>> data logging. >>> >>> The ones made for that purpose seem to be in the $150 range. >>> >>> Pressure transducers are not something I am looking at on a daily >>> basis >>> so I don't know what the going rate for off-the-shelf industrial >>> models >>> are, or where to buy them in single quantities. >>> >>> Basically brake fluid is fairly benign and the pressure is 0 to 1500 >>> PSI >>> and accuracy is not that important. And I don't care what the >>> input/output is, raw bridge, ratiometric, digital, whatever. >>> >>> Anyone been down this road before and can point me in the right >>> direction? >>> >>> Thanks, >>> >>> Bob >>> >>> >> Is there a company that makes a fluid isolator/pressure multiplier ? >> Maybe something mechanical that has a 10:1 ( as an example ) surface >> ratio change so that 2000 psi on one side is 200 psi on the other ? >> Gus >> > > > A good machinist with a lathe and a grinder can make such device. > A plunger inside a cylinder with an internal step (the plunger stepped > also), the cross section of the bigger diameter portion with an area ten > times that of the smaller diameter portion. > > High pressure applied to the smaller diameter end pushes the plunger, > the pressure at the larger diameter end is 1/10 of the pressure at the > smaller diameter end. > > The tricky part is the leakage, perhaps some O-Rings near each end with > a hole through the cylinder wall, between the sections to drain any > fluid that may leak from either side. > > The pressure reduction may be even higher, perhaps hundreds of times, to > suit any pressure sensor you may find. > > > A better option would be a device like this one but instead of using > pressure at the larger diameter end, just attach a strain-gauge and read > the pressure by means of the strain. > > Isaac > > __________________________________________________ > Fale com seus amigos de graça com o novo Yahoo! Messenger > http://br.messenger.yahoo.com/ > > This is a good idea I have worked on a device such as this on a machine I worked on. The drain hole in the m middle is very important. ALSO the seals used need special attention. I cannot remember details but some types of seal material will come apart when exposed to brake fluid. OLD BOB

> This is a good idea I have worked on a device such as this on a machine > I worked on. > The drain hole in the m middle is very important. > > ALSO the seals used need special attention. I cannot remember details > but some types of seal material will come apart when exposed to brake > fluid. > > Another slave cylinder (I think some folks call them wheel cylinder and from the wreckers or even new as they are cheap approx $20 last time I purchased one) in a sturdy cage with strain gauge. Using a real slave cylinder (or master cylinder) you can be confident that the correct materials are used.