DIY_EFI Digest Monday, 19 February 1996 Volume 01 : Number 047 In this issue: Re: TPS sensor (was MAP Questions...) Re: Tektronix ignition analysis 'scope book Really awesome TPS... MPX2200 Re: Really awesome TPS... Re: Sound Blaster as Data Aquisition Re: Really awesome TPS... Re: Sound Blaster as Data Aquisition See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: Donald Whisnant Date: Sun, 18 Feb 1996 12:41:39 -0500 Subject: Re: TPS sensor (was MAP Questions...) > >Jim Staff writes: > >> I don't know how to make a Throttle Position Sensor, But I'm sure >> somebody here know or I could find it out god knows I've found out >> impossible stuff already. > >Jim, head down to your local auto parts store and ask the guys behind the >counter to have a look at a Standard Motor Products or Echlin emission >controls catalog. These have nice little pictures of a zillion different >types of throttle position sensors, I'm sure you could find one to fit >your application. It's just a pot, hook the ends to 5V and ground and >read the voltage at the wiper to get throttle position. Resist the >temptation to just use a 99 cent pot from your local Radio Shack, they >are not made for the constant dithering and movement that a TPS sees. >Once you get this data, you're on your own... If you want to make a good TPS, you can get a high quality, wire wound 10 turn pot (like a Beckman or Bourns). This will require a little machine work (so having a machine shop or specialty parts is a must)... Make either a gear drive assembly or better yet, use a couple of timing belts and timing pulleys. This is required to convert the approx. 3/4" movement into a 10 turn movement. This will provide much better resolution and a MUCH better output signal. A 100K pot or something close would be good. Now, that is a "good TPS" but if you want and absolutely "fabulous TPS", and one that is even mil spec, you will need a Resolver and a Converter circuit. A resolver is a rotatary device that outputs a sine and cosine of the angle at which it is position. The military uses them in missile guidance systems. ... The great thing with a resolver is that it is basically frictionless PLUS it is VERY VERY accurate. AND, it is extremely water resistant (unlike your off the shelf pots) ... HOWEVER, they are expensive (about $300) and require a driver/converter circuit -- also another expensive piece... BUT, this would be the ULTIMATE in TPS sensors... Maybe someday, if I have some money to waste on a resolver, I'll give it a shot... Donald Whisnant dewhisna@xxx.com ------------------------------ From: Doug Rorem Date: Sun, 18 Feb 1996 14:32:06 -0600 Subject: Re: Tektronix ignition analysis 'scope book John, It looks like it was the very distant past (circa 1970).. However, it looks interesting and I doubt much has changed since that time, except for wider use of high energy ignition systems. It's not available at our library, I wonder if Tek still distributes it (not likely..) | AUTHOR: Thurman, Jim | TITLE: Engine analysis / | PLACE: Beaverton, Ore. : |PUBLISHER: Tektronix, | YEAR: 1970 | PUB TYPE: Book | FORMAT: 119 p. : ill. ; 23 cm. | SERIES: Measurement concepts | NOTES: Cover title: Engine analysis measurements. | Includes index. | SUBJECT: Engines -- Testing. | OTHER: Tektronix, Inc. | Engine analysis measurements. |_____________________________________________________________________________ - -- Doug Rorem University of Illinois at Chicago (312)-996-5439 [voice] EECS Department RM 1120 (312)-413-1065 [fax] 851 S. Morgan Street (708)-996-2226 [pager] Chicago, IL 60607-7053 rorem@xxx.edu ------------------------------ From: Timothy Coste Date: Sun, 18 Feb 1996 22:00:32 -0500 Subject: Really awesome TPS... Donald Whisnant (I believe) wrote... Now, that is a "good TPS" but if you want and absolutely "fabulous TPS", and one that is even mil spec, you will need a Resolver and a Converter circuit. A resolver is a rotatary device that outputs a sine and cosine of the angle at which it is position. The military uses them in missile guidance systems. ... The great thing with a resolver is that it is basically frictionless PLUS it is VERY VERY accurate. AND, it is extremely water resistant (unlike your off the shelf pots) ... HOWEVER, they are expensive (about $300) and require a driver/converter circuit -- also another expensive piece... BUT, this would be the ULTIMATE in TPS sensors... To which I reply... I'm not sure if these are exactly what you're talking about, but from a C&H Sales Company (surplus and misc sales) catalog... Bearing Module #blah This unit contains...the following: one resolver #CSHblah, one resolver #CVHblah, one differential, one motor tachometer...and many high precision and anti-backlash gears, precision bearings, standoffs, etc. Dim.... Price: $15 US. Obviously (I think) a mil. spec. fire control or such unit. They also have a Range Module with similar stuff. If these are what you speak of, and if they are durable enough to most likely still be in good shape, it may be a way to try your idea on the cheap. Your post jogged a little something loose in my brain (as if I can spare any little things being jarred from my brain) and I remembered reading about these things in this catalog and wondering what the heck they were (and might be good for). In the true spirit of diy, I really get into surplus catalogs. Just FIY... Tim Coste tlcoste@xxx.edu ------------------------------ From: ducharme@xxx.com (CF Ducharme) Date: Sun, 18 Feb 96 22:33:06 EST Subject: MPX2200 Sorry about the blank message - working from UNIX mail instead my usual MailTool can be a problem. Also, this UNIX box has two node names, hence the mixup on address. Yes, It's me (CF Ducharme is Cliff Ducharme) Any more info on the Motorola pressure sensor (price, sources, etc) would be appreciated. Yes there are (at least) two of us - Jim Staff doing a high mileage vehicle application with a B&S, and me doing a senior (43 year old senior?) design project for my BSEE. I believe Jim is using an Intel 286, and I'm using a Motorola M68HC11 (Coactive Aesthetics GCB11) and after graduation, if I'm bored I may try to port it to my '85 Electraglide - but, as they say, 'Things are different on a Harley...' I will probably post some of my project details to the DIY_EFI home page once things draw near a close. Cliff Ducharme ------------------------------ From: arthurok@xxx.com (ARTHUR OKUN ) Date: Sun, 18 Feb 1996 19:38:02 -0800 Subject: Re: Really awesome TPS... in those same catalogs you can find dusttite or even sealed one turn servo pots for a few dollars "ball bearing" 5k ohm or so. or how about a lvdt plymouth used those in the early days a plastic film pot is better then wire because the output signal has little electrical noise. ------------------------------ From: masmith Date: Sun, 18 Feb 1996 22:02:53 -0800 Subject: Re: Sound Blaster as Data Aquisition At 12:38 PM 2/17/96 MDT, Darrell A. Norquay wrote: > >Mark Boxsell wrote: > >> Yes! ,This is exactly what I was wondering maybe we all have a >> digital storage cro in our PC's after all! Has anyone out there seen any >> articles on this, I think the 'line in' accepts 0 - 250mV so you would have >> to put a front end of some kind on the thing. >> Whoever works out a kit for this will make a fortune. I don't have time at >> the moment so someone else will have to do it! > >The main problem with a sound blaster card is that it doesn't accept DC >signals. The inputs are capacitor coupled so they block DC. I think >it will go down to about 10Hz minimum frequency. It is made to digitize >audio, which probably wouldn't work for most sensor type inputs 'cause >they're mainly a slow changing DC signal. > > run the dc thru a voltage to frequency convertor first, then digitize with the sound blaster. you could then save the result as a wave file (am assuming PC with windows vs. eg mac) the format of a wave file is probably on the internet "somewhere" and "somewhere" on my hard disk is a MATLAB file that can read it as an array of numbers that can be FFTed, graphed, displayed or whatever. (or run the pitch thru a lookup table to reverse the v2f converter.) Matt Smith masmith089@xxx.com Mailer Eudora 1.5.2 ------------------------------ From: sandy Date: Mon, 19 Feb 1996 01:50:55 -0500 Subject: Re: Really awesome TPS... What is wrong with the CTS units found on many cars? I think that they now have one that uses a non-resistor approach, that uses a film with a gradation on it, then slides that between a photo transistor or something like that. It has the feature of not wearing out, and next to no noise. I saw it in an add in one of the Automotive Engineering mags. Sandy At 19:38 18/02/96 -0800, you wrote: >in those same catalogs you can find dusttite or even sealed one turn >servo pots for a few dollars "ball bearing" 5k ohm or so. >or how about a lvdt plymouth used those in the early days >a plastic film pot is better then wire because the output signal has >little electrical noise. > ********************************** Sandy Ganz sandyg@xxx.com Visix Software Inc. ********************************** ------------------------------ From: Brendan Simon Date: Mon, 19 Feb 1996 18:50:21 +1100 Subject: Re: Sound Blaster as Data Aquisition > run the dc thru a voltage to frequency convertor first, then digitize with > the sound blaster. > you could then save the result as a wave file (am assuming PC with windows > vs. eg mac) > the format of a wave file is probably on the internet "somewhere" and > "somewhere" on my hard > disk is a MATLAB file that can read it as an array of numbers that can be > FFTed, graphed, displayed > or whatever. (or run the pitch thru a lookup table to reverse the v2f > converter.) > Matt Smith > masmith089@xxx.com > Mailer Eudora 1.5.2 What kind of accuracy can you get (do you expect) from such a system ?? I would think it would not be as good as direct DC sampling. Any comments from anyone who has tried ??? - -- Brendan Simon Dept of Digital Systems, Monash Uni, Melbourne, Australia. brendan@xxx.au http://www.rdt.monash.edu.au/~brendan ------------------------------ End of DIY_EFI Digest V1 #47 **************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".