From owner-diy_efi Tue Sep 6 18:24:20 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA03410; Tue, 6 Sep 94 18:24:20 GMT Received: from localhost.eng.ohio-state.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA03399; Tue, 6 Sep 94 14:24:16 -0400 Message-Id: <9409061824.AA03399@coulomb.eng.ohio-state.edu> To: DIY_EFI Cc: jsg Subject: Re: frequency to voltage conversion. In-Reply-To: Your message of "Tue, 06 Sep 94 12:00:59 EDT." <940906120059.18c1@abacus.gsfc.nasa.gov> Date: Tue, 06 Sep 94 14:24:16 -0400 From: John S Gwynne Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI -------- In message <940906120059.18c1@abacus.gsfc.nasa.gov> , you write: | | >MAP and BP sensors apparently do not return voltage as output. Instead | >the oscillate at a frequency which corresponds to the absolute pressure. | >What electronics are involved with frequency to voltage conversion? | | Your best bet for accuracy is a frequency counter - this would also tend to | eliminate noise (a digital filter if you will). | | Suppose you find out the MAP sensor outputs between 50-150 HZ depending | on pressure. Hook up an 8-bit counter and read it every 10Hz. You'll expect | readings between 5-15 counts - this is a little low on accuracy but allows fo That's why the counter circuit I posted a while back is a period counter *not* a frequency counter. With it's 16-bit pre-scalar and 32-bit count register running at 10MHz, this task is becomes trivial. Set the pre-scalar to say 4 or 5 cycles, and you will have fast accurate data.... I've used this circuit to measure frequency as high as 4MHz to one time event lasting up to seven minutes. Take a look at it; it's only 3 or 4 chips. John S Gwynne Gwynne.1@osu.edu _______________________________________________________________________________ T h e O h i o - S t a t e U n i v e r s i t y ElectroScience Laboratory, 1320 Kinnear Road, Columbus, Ohio 43212, USA Telephone: (614) 292-7981 * Fax: (614) 292-7292 ------------------------------------------------------------------------------- From owner-diy_efi Tue Sep 6 18:38:38 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA03563; Tue, 6 Sep 94 18:38:38 GMT Received: from gw1.att.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA03558; Tue, 6 Sep 94 14:38:36 -0400 Received: from uscbu.ih.att.com by ig1.att.att.com id AA11283; Tue, 6 Sep 94 14:37:29 EDT Received: by uscbu.ih.att.com (4.1/EMS-1.0.2 main.cf 1.37 10/5/93 (SMI-4.1/SVR4)) id AA18918; Tue, 6 Sep 94 13:38:10 CDT From: Bohdan.L.Bodnar@att.com Received: from usgp1.ih.att.com by uscbu.ih.att.com (4.1/EMS-1.0.2 main.cf 1.37 10/5/93 (SMI-4.1/SVR4)) id AA18911; Tue, 6 Sep 94 13:38:07 CDT Received: by usgp1.ih.att.com (5.0/EMS-1.1 client.cf 1/8/94 (SMI-4.1/SVR4)) id AA21418; Tue, 6 Sep 1994 13:38:48 +0600 Date: Tue, 6 Sep 1994 13:38:48 +0600 Message-Id: <9409061838.AA21418@usgp1.ih.att.com> Original-From: bohdan@uscbu.ih.att.com (Bohdan L Bodnar) To: DIY_EFI Subject: Re: FW: Frequency to Voltage Conversion: how? Content-Type: text Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI Comments and useful information... > Someone writes: > >MAP and BP sensors apparently do not return voltage as output. Instead >the oscillate at a frequency which corresponds to the absolute pressure. >What electronics are involved with frequency to voltage conversion? > >>This brings up another point: what output frequency corresponds to what >>pressure level? I'm sure we could test one to find out, but isn't there >>already some book or manual that gives in depth data on sensor readings? >>If we have to test every sensor, it is going to take a LONG time. Surely >>Ford, Chevy, and/or Bosch, publishes a manual for servicing EFI that >>describes how each particular type of sensor responds. >> >> Most single chip computers can measure frequency much better than voltage, >>which is why MAF sensors output frequency. Since I don't know the frequency >>range for this sensor, I can't comment on the best circut to do a freq. to >>voltage conversion. >> My GM map sensor outputs a voltage proportional to the pressure *and >>reference voltage*. I did a pressure calibration and found it to be extreemly >>linear and very dependent on ref. voltage. Three terminals: ground, ref in, >>and output voltage. I gave mine 5.0 volts. I don't have the data handy, but >>can post if you would wish. I plan on calibrating all that I own to find out >>repeatability info. The MAP sensor I use is used in my '89 Berettas (4 and 6 >>cyl), my sister's '89 Corsica, and my friend's Jeep. >> - Steven ciciora Steven, et al, With the exception of Ford's MAP/BP sensors, I know of no other major manufacturer which uses a digital output MAP/BP sensor; all others use an analog output. The pressure/frequency relationship is given in Ford's customer training literature; if there's enough interest, I can post the table. Typically, about 155 Hz is atmospheric pressure (157 Hz, +/- 1 Hz, yesterday afternoon in Chicago -- I was working on an emission problem on my Mustang) with the frequency being around 80 Hz at about 23" Hg vacuum. The comment about frequency measurement and MAF output is not quite true. I know of NO technical reason why frequency measurements are easier than voltage measurements -- both are easy to do in real-time (keep in mind that "real-time" in a automotive engine control environment is about 10 samples/second). In one case, averaged period measurements are used to indirectly obtain frequency whereas in the other analog to digital conversion is used; I suspect the latter doesn't even use sample-and-hold amplifiers since the input signals change so slowly w.r.t. the conversion rate (around 20 microseconds for a typical 8-bit successive approximation converter using a 1 MHz clock). Any MAF system based on currently deployed Bosch technology will have an analog output from the MAF sensor with approximately reference voltage (5.0v nominal) corresponding to atmospheric pressure. This covers most Chrysler, most 1980s GM stuff, and virtually all Japanese vehicles. The "virtually" excludes stuff using the Hitachi MAF sensor (a high-frequency digital output) and the Chrysler import which uses the Karman-vortex sensor (Dodge Colt?). Cordially, Bohdan Bodnar bohdan.l.bodnar@att.com From owner-diy_efi Tue Sep 6 19:58:58 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA03707; Tue, 6 Sep 94 19:58:58 GMT Received: from heifetz.msen.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA03692; Tue, 6 Sep 94 15:58:51 -0400 Received: from edgewd.UUCP by heifetz.msen.com with UUCP (Smail3.1.28.1 #12) id m0qi5rX-000ZXzC; Tue, 6 Sep 94 15:07 EDT Received: from msm.edgewood.com by edgewd.edgewood.com (4.1/SMI-4.1) id AA18963; Tue, 6 Sep 94 15:07:38 EDT Received: from msm.edgewood.com by edgewd.edgewood.com (4.1/SMI-4.1) id AA18963; Tue, 6 Sep 94 15:07:38 EDT Received: by msm.edgewood.com with Microsoft Mail id <2E6CDF91@msm.edgewood.com>; Tue, 06 Sep 94 14:30:57 PDT From: Donald Day To: EFI Mail List Subject: EFI suggestions Date: Tue, 06 Sep 94 09:23:00 PDT Message-Id: <2E6CDF91@msm.edgewood.com> Encoding: 21 TEXT X-Mailer: Microsoft Mail V3.0 Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI Hello all, I am looking for engine management / data-acq alternatives for a 1986 Corvette. I am already aware of the offerings from Accel and I also believe that there is a company in AZ. doing simular EFI retrofits to older carbed cars. I am hoping on finding a more integrated solution that will allow me to combine some other types of data-gathering (RPM, Braking, G-forces, etc..) along with an engine management system. Thanks in advance. BTW I just subscribed so if this falls under a FAQ condition my apoligies. Donald Day dday@msm.edgewood.com From owner-diy_efi Tue Sep 6 20:35:25 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA04041; Tue, 6 Sep 94 20:35:25 GMT Received: from localhost.eng.ohio-state.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA04035; Tue, 6 Sep 94 16:35:23 -0400 Message-Id: <9409062035.AA04035@coulomb.eng.ohio-state.edu> To: DIY_EFI Subject: software organization... Date: Tue, 06 Sep 94 16:35:22 -0400 From: John S Gwynne Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI -------- For those of you interested in the software aspect of DIY_EFI, take a look at the uC/OS real-Time multitasking kernel (ftp.uu.net in vendor/microplex/pub). I'm porting this to my 68000 board and it looks like it will simplify the timing problem associated with the sampling of the various sensors. For example, it can be setup to sample the coolant sensor once every minute, the air inlet temp once every second, and calculate injector duration every 100mS. The kernel manages the timing and priority of the process for you. John S Gwynne Gwynne.1@osu.edu _______________________________________________________________________________ T h e O h i o - S t a t e U n i v e r s i t y ElectroScience Laboratory, 1320 Kinnear Road, Columbus, Ohio 43212, USA Telephone: (614) 292-7981 * Fax: (614) 292-7292 ------------------------------------------------------------------------------- From owner-diy_efi Tue Sep 6 22:05:52 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA04281; Tue, 6 Sep 94 22:05:52 GMT Received: from smtp.utexas.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA04276; Tue, 6 Sep 94 18:05:50 -0400 Received: from mail.utexas.edu (mail.utexas.edu [128.83.126.1]) by smtp.utexas.edu (8.6.7/8.6.6) with ESMTP id RAA25702 for ; Tue, 6 Sep 1994 17:05:05 -0500 From: BigBrother@mail.utexas.edu Received: from [128.83.128.164] (slip-14-4.ots.utexas.edu [128.83.128.164]) by mail.utexas.edu (8.6.7/8.6.6) with SMTP id RAA25449 for ; Tue, 6 Sep 1994 17:04:52 -0500 Message-Id: <199409062204.RAA25449@mail.utexas.edu> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Tue, 6 Sep 1994 17:04:35 -0600 To: DIY_EFI Subject: Frequency to Voltage Conversion- Thanks Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI > (Dan Bocek writes) > > While it is true that some airflow measuring techniques have a frequency > output (the Karmen-vortex sensor, as used on a lot of Mitsubishi cars, > comes to mind, although its output is pulse width modulated, so all you > have to do is low pass filter the output to get DC) I've never heard of > a MAP sensor outputting AC. Where did you get this info? I found out that MAP and BP sensors (at least Ford) output frequency instead of DC voltage from a Ford EFI book. Of course most new Ford's don't use the MAP (or BP as it is called now) to measure mass air. They just use a MAP sensor hooked up to nothing to measure barometeric pressure. That is why it has been renamed the 'BP' sensor. Mass air sensing comes from a hot-wire type MAF sensor. Anyway, thanks to everybody for the pointers on frequency sampling techniques. If I wasn't forced to take so many b.s. classes before the real EE stuff, I wouldn't have to ask! From owner-diy_efi Wed Sep 7 15:01:35 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA06760; Wed, 7 Sep 94 15:01:35 GMT Received: from tomcat.al.noaa.gov by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA06755; Wed, 7 Sep 94 11:01:33 -0400 Received: from aztec.al.noaa.gov by tomcat.al.noaa.gov with SMTP id AA19129 (5.65c/IDA-1.4.4 for ); Wed, 7 Sep 1994 09:07:11 -0600 Message-Id: <199409071507.AA19129@tomcat.al.noaa.gov> Date: 7 Sep 1994 09:00:01 U From: "Ciciora Steve" Subject: FW: software organization... To: DIY_EFI Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI _______________________________________________________________________________ John writes: -------- For those of you interested in the software aspect of DIY_EFI, take a look at the uC/OS real-Time multitasking kernel (ftp.uu.net in vendor/microplex/pub). I'm porting this to my 68000 board and it looks like it will simplify the timing problem associated with the sampling of the various sensors. For example, it can be setup to sample the coolant sensor once every minute, the air inlet temp once every second, and calculate injector duration every 100mS. The kernel manages the timing and priority of the process for you. John S Gwynne Gwynne.1@osu.edu _______________________________________________________________________________ John, This sounds like the kernal I've seen on the Motorola BBS for the 6811. Is it? Since you will be porting it (from what, if not the 6811), I assume you will soon understand it pretty well. I've been meaning to check out real time kernals for some time, but they have always seem to be a little over my head or require a C compiler. When you understand it a little better, could you give us a breif overview? How much overhead does it require (size/time)? Thanks for helping keeping the project rolling! - Steven Ciciora From owner-diy_efi Wed Sep 7 17:20:57 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA07155; Wed, 7 Sep 94 17:20:57 GMT Received: from wotan.compaq.com by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA07148; Wed, 7 Sep 94 13:20:54 -0400 Received: from twisto.eng.hou.compaq.com by wotan.compaq.com with smtp (Smail3.1.28.1 #11) id m0qiQMh-000vKfC; Wed, 7 Sep 94 12:00 CDT Received: from bangate.compaq.com by twisto.eng.hou.compaq.com with smtp (Smail3.1.28.1 #10) id m0qiQM3-000uH7C; Wed, 7 Sep 94 12:00 CDT Message-Id: Received: by bangate.compaq.com with VINES ; Wed, 7 Sep 94 12:00:16 CDT Date: Wed, 7 Sep 94 11:23:24 CDT From: Steve=Ravet%Prj=Eng%PCPD=Hou@bangate.compaq.com Subject: mp kernel To: diy_efi Cc: Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI John wrote: For those of you interested in the software aspect of DIY_EFI, take a look at the uC/OS real-Time multitasking kernel (ftp.uu.net in vendor/microplex/pub). I'm porting this to my 68000 board and it looks like it will simplify the timing problem associated with the sampling of the various sensors. For example, it can be setup to sample the coolant sensor once every minute, the air inlet temp once every second, and calculate injector duration every 100mS. The kernel manages the timing and priority of the process for you. ---------------------------------------------------------------------------- John -- I understand you are using a GCC cross compiler for your 68000. As long as you are on a unix system, GCC is easy to configure as a cross-compiler. If there's interest, I can dust off my linux, get the sources and build a compiler. Actually, I'll go ahead and do that unless someone else has done it or is doing it. It'd be nice to have a DOS cross-compiler, though, anyone know if there is one out there? What is the chance of getting an etched version of your CPU board. I hate wire wrapping, but I'd be willing to pay a few dollars to get an etched board. I know getting small batches of PC boards is a FAQ on sci.electronics,I'll have a look and see if I can get any info. If anyone else here has connections for getting etching done, please speak up. --steve From owner-diy_efi Thu Sep 8 02:44:45 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA10116; Thu, 8 Sep 94 02:44:45 GMT Received: from relay1.UU.NET by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA10110; Wed, 7 Sep 94 22:44:37 -0400 Received: from camelot.dsccc.com by relay1.UU.NET with SMTP id QQxgkg19875; Wed, 7 Sep 1994 22:44:28 -0400 Received: from optilink.dsccc.com by camelot.dsccc.com (5.65c/SMI-V1.8) id AA15103; Wed, 7 Sep 1994 21:47:56 -0500 Received: from montreal by optilink.dsccc.com (4.1/SMI-4.0) id AA02733; Wed, 7 Sep 94 11:06:08 PDT From: marrone@optilink.dsccc.com (Frank Marrone) Message-Id: <9409071101.ZM233@montreal> Date: Wed, 7 Sep 1994 11:01:21 -0700 In-Reply-To: Bohdan.L.Bodnar@att.com "Re: FW: Frequency to Voltage Conversion: how?" (Sep 6, 1:38pm) References: <9409061838.AA21418@usgp1.ih.att.com> X-Mailer: Z-Mail (3.0.1 23feb94) To: DIY_EFI Subject: Re: FW: Frequency to Voltage Conversion: how? Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI > measurements -- both are easy to do in real-time (keep in mind that > "real-time" in a automotive engine control environment is about 10 > samples/second). This reminds me of a question I have always wondered about DIY EFI (and DLI as well) and perhaps this is the answer but I'll speak my question out loud anyway; What sort of aquisition/output update rate is required to eliminate errors due to the acceleration (+/-) of the motor internals? It seems that many high-po engines could accelerate at a rate that would make data at a 10sps rate kind of useless. If the the 10sps rate is just for MAP I guess I could buy it since air as a mass has inertia and all but what about ignition? How often are you required to sense crank position to eliminate acceleration errors for spark control? Other supervisory/control tasks? P.S. With reference to the smart supply: It might be that I am volenteering but I just got back from vacation and I need to think about the specs you posted before I get in too deep. I am still reverse engineering a knock box for someone and while it is very interesting I do have my own projects I would like to get started as well. -- Frank Marrone at marrone@optilink.dsccc.com 1965 Sunbeam Tiger B9471116 From owner-diy_efi Thu Sep 8 04:10:59 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA10252; Thu, 8 Sep 94 04:10:59 GMT Received: from localhost.eng.ohio-state.edu by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA10241; Thu, 8 Sep 94 00:10:56 -0400 Message-Id: <9409080410.AA10241@coulomb.eng.ohio-state.edu> To: DIY_EFI Cc: jsg Subject: Re: mp kernel In-Reply-To: Your message of "Wed, 07 Sep 94 11:23:24 CDT." Date: Thu, 08 Sep 94 00:10:56 -0400 From: John S Gwynne Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI | John -- I understand you are using a GCC cross compiler for your 68000. As | long as you are on a unix system, GCC is easy to configure as a | cross-compiler. If there's interest, I can dust off my linux, get the sources | and build a compiler. Actually, I'll go ahead and do that unless someone else | has done it or is doing it. It'd be nice to have a DOS cross-compiler, | though, anyone know if there is one out there? DJGPP is a DOS version of GCC (as I understand it). It may be possible to build the cross-compiler with that. (???) IMHO, linux is the way to go; but I'm a unix person and nearly pc illiterate :). There are other cross-compilers out there but keep in mind that it take more than just a compiler for good software development. With the GNU stuff, we also have the assembler (GAS), the binary utilities, the debugger (gdb), and the standard C library (glibc). I've used the m68k-sun-sunos4 target for everything. I will be happy to throw in my "two cent" for anyone interested in doing this. | What is the chance of getting an etched version of your CPU board. I hate | wire wrapping, but I'd be willing to pay a few dollars to get an etched board. | I know getting small batches of PC boards is a FAQ on sci.electronics,I'll | have a look and see if I can get any info. If anyone else here has | connections for getting etching done, please speak up. 6"x4" board with maybe 4 layers.... I could generate the complete layout, but I would rather spend the time working on the companion board if someone else could do that. Let us know what you find in terms of cost. I don't really want to start an endless CPU debate (and certainly not a "bye y'all" type flame war :):) ), but the development tools for the 68XXX are here, free, and good. I ordered a 68HC811E2FN last week, and will build the coactive gcc port for it; however, I don't believe the development environment will be as good. YMMV. (FYI: The 68k will be the primary CPU for my EFI project, but I may use the 68hc11 under the hood to minimize the number of wires running into the passenger compartment.) John S Gwynne Gwynne.1@osu.edu _______________________________________________________________________________ T h e O h i o - S t a t e U n i v e r s i t y ElectroScience Laboratory, 1320 Kinnear Road, Columbus, Ohio 43212, USA Telephone: (614) 292-7981 * Fax: (614) 292-7292 ------------------------------------------------------------------------------- From owner-diy_efi Thu Sep 8 07:20:13 1994 Received: by coulomb.eng.ohio-state.edu (920330.SGI/920502.SGI) id AA10659; Thu, 8 Sep 94 07:20:13 GMT Received: from rain.org by coulomb.eng.ohio-state.edu via SMTP (920330.SGI/920502.SGI) for /usr/local/mail/majordomo-1.92/wrapper resend -p bulk -M 10000 -l Diy_Efi -f Diy_Efi-Owner -h coulomb.eng.ohio-state.edu -s -r DIY_EFI diy_efi-outgoing id AA10654; Thu, 8 Sep 94 03:20:09 -0400 Received: from diginst.UUCP by rain.org with UUCP (4.1/25-eef) id AA21911; Thu, 8 Sep 94 00:17:07 PDT Received: by di.com (UUPC/extended 1.11z); Thu, 08 Sep 1994 00:02:23 PDT Date: Thu, 08 Sep 1994 00:02:22 PDT From: "Dan Bocek" Message-Id: <2e6eb6ff.diginst@di.com> Organization: Digital Instruments, Santa Barbara, CA To: "diy_efi"DIY_EFI Subject: sensor vendors Sender: owner-diy_efi Precedence: bulk Reply-To: DIY_EFI There seems to have been a lot of talk about what type of sensors are needed for an EFI system, but not much about where to get them (aside from the junk yard - tough to get data on those!). I need a cheap pressure transducer (prefferably PC board mountable) that can measure 0 to ~45 psi absolute pressure and that can stand up to the high tempurature of turbocharged whipped up air and to the dissolving effect of the occasional gasoline/oil/hydrocarbon molecule that's bound to fly through it every now and then. I've seen plenty of adds for this type of transducer in "Sensor" magazine, but they're all designed for industrial applications, and are a coupla hundred bucks apiece! Where does the automotive industry buy their sensors? How do you buy stuff from Bosch directly? Since people also seem to be interested in knock sensors, does anyone know anything more about the Analog Devices part number AD22030 than is mentioned in the feeble preliminary data sheet? It's listed as a monolithic, dual input knock-sensor interface circuit - it would be perfect for our application - but I have a feeling it's probably just vapor-ware. Just wondering if anyone knows anything about it. -- Dan Bocek dan@di.com