Re: [MBZ] Project to tickle your brains with..
I tried the oft-suggested trick of wedging something between the module and the cover, and it was always just a temporary fix. Yeah, you need to clean the contact pins, _and_ clean and close down the sockets too, which requires disassembling the piece that bolts to the fender. Contact cleaner is also a good idea. Takes a bit of time. -- Jim
Re: [MBZ] Project to tickle your brains with..
is this a kit or schematic purchase??? :) On Fri, 10 Nov 2006 15:57:03 -0600, Trampas [EMAIL PROTECTED] wrote: I have a small circuit board that will convert a crank sensor (inductive pickup) to a TTL signal. I also have a device that has an LCD for displaying the data. The problem with the crank sensor is that as I recall it only triggers once per revolution, I am not sure what the tachometer is looking for but I can find out as I have a 300SD. By the way here are some of the products I have built, www.sterntech.com Trampas -- Luther KB5QHUAlma, Ark '87 300SDL (270,491 mi) head case? '83 300SD (241 kmi) '82 300CD (162 kmi) '82 300D (74 kmi) needs MAJOR engine work '85 300D (280,176) parts car
Re: [MBZ] Project to tickle your brains with..
Since I mainly work with surface mount devices I just sell the products assembled and tested. I am just now in the process of putting all the code up on the web under the GNU public license such that if you do not like the way it works you are free to change it. Trampas -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Luther Sent: Friday, November 10, 2006 8:42 PM To: Mercedes Discussion List Subject: Re: [MBZ] Project to tickle your brains with.. is this a kit or schematic purchase??? :) On Fri, 10 Nov 2006 15:57:03 -0600, Trampas [EMAIL PROTECTED] wrote: I have a small circuit board that will convert a crank sensor (inductive pickup) to a TTL signal. I also have a device that has an LCD for displaying the data. The problem with the crank sensor is that as I recall it only triggers once per revolution, I am not sure what the tachometer is looking for but I can find out as I have a 300SD. By the way here are some of the products I have built, www.sterntech.com Trampas -- Luther KB5QHUAlma, Ark '87 300SDL (270,491 mi) head case? '83 300SD (241 kmi) '82 300CD (162 kmi) '82 300D (74 kmi) needs MAJOR engine work '85 300D (280,176) parts car ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] Project to tickle your brains with..
IE - If I were to try this route to put a tach in my 76 300D, I assume I would have to attach something to the balancer to trigger the sensor as there would not be anything from the factory. The MB tachometers used a variable-reluctance sensor, which is just a coil of wire around a metal core, placed near a moving metal part. Current is run through the coil, and whenever the moving metal part (a pin stuck in the side of the balancer) whips by the core it changes the inductance, which induces a change in voltage across the coil. This blip is amplified and signal-conditioned for use. Extremely simple and durable, and immune to dirt, etc. Immune to heat, until the wire insulation melts, etc. Dirt-cheap too. Hard to beat it. Later cars moved the VR sensor back to the ring gear teeth, which multiplied the frequency by about 144 IIRC. But otherwise the circuitry remained about the same. The same technique is used in ABS sensors. I have a small circuit board that will convert a crank sensor (inductive pickup) to a TTL signal. That, of course, is exactly the sort of thing that is in the venerable tach can from the 617 cars. The problem with the crank sensor is that as I recall it only triggers once per revolution, I am not sure what the tachometer is looking for but I can find out as I have a 300SD. Not a problem, just a characteristic. MB tachs either wanted 1 pulse/rev or 144/rev. (See above.) If you want me to send you one I can, note that the LM1815 has a maximum voltage of 12V, thus it should be powered from a regulator. I can't find my notes, but the stock tach amplifier uses one of the National chips in it, it might be this one. Whatever it is it works well and lives long, I don't think it has a voltage regulator in the can. The circuit in the can is lifted almost directly from the app. note, that I do remember. What all would I need to have a tach setup on a 76 115 300D? To use a stock MB parts, you'd need to have a pin on the harmonic balancer or pulley, and a VR sensor mounted near it. (Your car may already have the pin, you'll have to look.) Then the tach can amplifier from a wrecked car, and then whatever stock tachometer you can live with. A suggestion might be to use the tach from a 6.3, don't those go into the cluster in place of the clock? Tres cool, if so. (Though personally I'd rather have the clock.) The tach will need adjustment to read correctly. Most aftermarket tachs (used to, anyway) have knobs inside to tune them to the application, I suspect that a vintage tach would be easily adaptable. The things are (were) all built to feed off points, and where there were none circuitry simulated them. - Jim
Re: [MBZ] Project to tickle your brains with..
Jim Cathey wrote: To use a stock MB parts, you'd need to have a pin on the harmonic balancer or pulley, and a VR sensor mounted near it. (Your car may already have the pin, you'll have to look.) Then the tach can amplifier from a wrecked car, and then whatever stock tachometer you can live with. One from a wrecked car may or may not be good. People seem to have a lot of problems with the tach cans going intermittent when they get older. (Mine did.)
Re: [MBZ] Project to tickle your brains with..
Jim Cathey wrote: One from a wrecked car may or may not be good. People seem to have a lot of problems with the tach cans going intermittent when they get older. (Mine did.) The problem there seems to be almost always poor contact between the pins on the circuit board and the connector socket. That can be dealt with in a couple of ways. I've had it happen myself. I tried the oft-suggested trick of wedging something between the module and the cover, and it was always just a temporary fix.
Re: [MBZ] Project to tickle your brains with..
How about using an embedded device (like a Basic Stamp or similar) and counting some pulse coming from the alternator and using that to drive the tach input? Would that work? Thoughts? Jim? You could. Alternators don't put out a pulse, but they do have a bit of ripple that can be amplified. However now you're into the same kind of circuitry that is in the usual tach can amplifier. Given the relatively ready supply of junkyard parts, I can't see any reason not to just use them, it's nearly trivial. (As I believe the front crank sensor is already there, at least on a lot of cars. Goes to the diagnostic socket.) Even if you have to install a factory sensor, it has to be easier than flanging up something yourself. And running it all over, and designing circuitry. Same reason I used a defogger relay as the basis for my road trip relay. An easier place to start than from scratch. You've already go the hard part done, the cluster is installed. Now just run a cable to the can, and power, and then run the cable to the crank sensor. You're done. (Worst case. Best case most of it is already there.) -- Jim
Re: [MBZ] Project to tickle your brains with..
What triggers the crank sensor on most new cars? Is there a magnet inbedded in the crank dampener/balancer/pulley (whatever you wish to call it)? IE - If I were to try this route to put a tach in my 76 300D, I assume I would have to attach something to the balancer to trigger the sensor as there would not be anything from the factory. Randy -Original Message- Given the relatively ready supply of junkyard parts, I can't see any reason not to just use them, it's nearly trivial. (As I believe the front crank sensor is already there, at least on a lot of cars. Goes to the diagnostic socket.) Even if you have to install a factory sensor, it has to be easier than flanging up something yourself. And running it all over, and designing circuitry. -- Jim ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] Project to tickle your brains with..
You could do an LED and a light sensor with a white mark on the crank, of course that would be affected by whatever goop gets splashed up there, but something to wipe it off as it goes around... --R R A Bennell wrote: What triggers the crank sensor on most new cars? Is there a magnet inbedded in the crank dampener/balancer/pulley (whatever you wish to call it)? IE - If I were to try this route to put a tach in my 76 300D, I assume I would have to attach something to the balancer to trigger the sensor as there would not be anything from the factory. Randy -Original Message- Given the relatively ready supply of junkyard parts, I can't see any reason not to just use them, it's nearly trivial. (As I believe the front crank sensor is already there, at least on a lot of cars. Goes to the diagnostic socket.) Even if you have to install a factory sensor, it has to be easier than flanging up something yourself. And running it all over, and designing circuitry. -- Jim ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] Project to tickle your brains with..
Yes, I saw the post yesterday with the link to Roger Brown's site. I knew about him from my travels on the net relating to old Toyota 4X4s. The idea of using a crank sensor appeals. I just wondered what else I needed. Randy -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Rich Thomas Sent: Friday, November 10, 2006 11:37 AM To: Mercedes Discussion List Subject: Re: [MBZ] Project to tickle your brains with.. You could do an LED and a light sensor with a white mark on the crank, of course that would be affected by whatever goop gets splashed up there, but something to wipe it off as it goes around... --R R A Bennell wrote: What triggers the crank sensor on most new cars? Is there a magnet inbedded in the crank dampener/balancer/pulley (whatever you wish to call it)? IE - If I were to try this route to put a tach in my 76 300D, I assume I would have to attach something to the balancer to trigger the sensor as there would not be anything from the factory. Randy -Original Message- Given the relatively ready supply of junkyard parts, I can't see any reason not to just use them, it's nearly trivial. (As I believe the front crank sensor is already there, at least on a lot of cars. Goes to the diagnostic socket.) Even if you have to install a factory sensor, it has to be easier than flanging up something yourself. And running it all over, and designing circuitry. -- Jim
Re: [MBZ] Project to tickle your brains with..
I have a small circuit board that will convert a crank sensor (inductive pickup) to a TTL signal. I also have a device that has an LCD for displaying the data. The problem with the crank sensor is that as I recall it only triggers once per revolution, I am not sure what the tachometer is looking for but I can find out as I have a 300SD. By the way here are some of the products I have built, www.sterntech.com Trampas -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of R A Bennell Sent: Friday, November 10, 2006 3:47 PM To: Mercedes Discussion List Subject: Re: [MBZ] Project to tickle your brains with.. Yes, I saw the post yesterday with the link to Roger Brown's site. I knew about him from my travels on the net relating to old Toyota 4X4s. The idea of using a crank sensor appeals. I just wondered what else I needed. Randy -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Rich Thomas Sent: Friday, November 10, 2006 11:37 AM To: Mercedes Discussion List Subject: Re: [MBZ] Project to tickle your brains with.. You could do an LED and a light sensor with a white mark on the crank, of course that would be affected by whatever goop gets splashed up there, but something to wipe it off as it goes around... --R R A Bennell wrote: What triggers the crank sensor on most new cars? Is there a magnet inbedded in the crank dampener/balancer/pulley (whatever you wish to call it)? IE - If I were to try this route to put a tach in my 76 300D, I assume I would have to attach something to the balancer to trigger the sensor as there would not be anything from the factory. Randy -Original Message- Given the relatively ready supply of junkyard parts, I can't see any reason not to just use them, it's nearly trivial. (As I believe the front crank sensor is already there, at least on a lot of cars. Goes to the diagnostic socket.) Even if you have to install a factory sensor, it has to be easier than flanging up something yourself. And running it all over, and designing circuitry. -- Jim ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] Project to tickle your brains with..
The inductive pick up schematic is here: www.patentranch.com/tempfiles/inductive_schematic.pdf If you want me to send you one I can, note that the LM1815 has a maximum voltage of 12V, thus it should be powered from a regulator. For those of you wondering it was designed to be an interface board for the small engine monitor I made, which incidentally I will be releasing as open source as soon as I get my website redesigned. Also the OBDII device will be open source as well. Overall as mentioned before it is far easier to get the correct parts than to hack something together. Trampas -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Trampas Sent: Friday, November 10, 2006 4:57 PM To: 'Mercedes Discussion List' Subject: Re: [MBZ] Project to tickle your brains with.. I have a small circuit board that will convert a crank sensor (inductive pickup) to a TTL signal. I also have a device that has an LCD for displaying the data. The problem with the crank sensor is that as I recall it only triggers once per revolution, I am not sure what the tachometer is looking for but I can find out as I have a 300SD. By the way here are some of the products I have built, www.sterntech.com Trampas -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of R A Bennell Sent: Friday, November 10, 2006 3:47 PM To: Mercedes Discussion List Subject: Re: [MBZ] Project to tickle your brains with.. Yes, I saw the post yesterday with the link to Roger Brown's site. I knew about him from my travels on the net relating to old Toyota 4X4s. The idea of using a crank sensor appeals. I just wondered what else I needed. Randy -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Rich Thomas Sent: Friday, November 10, 2006 11:37 AM To: Mercedes Discussion List Subject: Re: [MBZ] Project to tickle your brains with.. You could do an LED and a light sensor with a white mark on the crank, of course that would be affected by whatever goop gets splashed up there, but something to wipe it off as it goes around... --R R A Bennell wrote: What triggers the crank sensor on most new cars? Is there a magnet inbedded in the crank dampener/balancer/pulley (whatever you wish to call it)? IE - If I were to try this route to put a tach in my 76 300D, I assume I would have to attach something to the balancer to trigger the sensor as there would not be anything from the factory. Randy -Original Message- Given the relatively ready supply of junkyard parts, I can't see any reason not to just use them, it's nearly trivial. (As I believe the front crank sensor is already there, at least on a lot of cars. Goes to the diagnostic socket.) Even if you have to install a factory sensor, it has to be easier than flanging up something yourself. And running it all over, and designing circuitry. -- Jim ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] Project to tickle your brains with..
Very interesting but you will need to tell me more about how to do this. I took some electronics in high school but that was long long ago and I have not done much of that sort of thing since. What all would I need to have a tach setup on a 76 115 300D? Based upon what has been suggested in the posts over the past couple of days, one should be able to come up with a means of triggering some sort of signal from either a crank sensor (magnetic??) or via a photosensor of some sort. How to then use the signal to produce a reading on a tach is beyond me. I read part of Roger Brown's article on the photosensor setup on the Rabbit diesel and I understand to some extent what he is doing. I assume the signal from the crank sensor would be essentially the same? IE - you get an electric pulse of some sort on every revolution (or more than once depending on the setup) and you use that to feed circuitry of some sort that permits the tach to read it and tell how many pulses it sees. What would I want for a tach? Roger Brown is using a small digital tach. I guess the 300D might look more period correct with an analog instrument of some sort but this is not going to be something that I use for running up to redline between shifts like one might do with a hotrod Mustang so it really is not critical what it looks like so long as it can be made to work well. Randy -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Trampas Sent: Friday, November 10, 2006 4:10 PM To: 'Mercedes Discussion List' Subject: Re: [MBZ] Project to tickle your brains with.. The inductive pick up schematic is here: www.patentranch.com/tempfiles/inductive_schematic.pdf If you want me to send you one I can, note that the LM1815 has a maximum voltage of 12V, thus it should be powered from a regulator. For those of you wondering it was designed to be an interface board for the small engine monitor I made, which incidentally I will be releasing as open source as soon as I get my website redesigned. Also the OBDII device will be open source as well. Overall as mentioned before it is far easier to get the correct parts than to hack something together. Trampas -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Trampas Sent: Friday, November 10, 2006 4:57 PM To: 'Mercedes Discussion List' Subject: Re: [MBZ] Project to tickle your brains with.. I have a small circuit board that will convert a crank sensor (inductive pickup) to a TTL signal. I also have a device that has an LCD for displaying the data. The problem with the crank sensor is that as I recall it only triggers once per revolution, I am not sure what the tachometer is looking for but I can find out as I have a 300SD. By the way here are some of the products I have built, www.sterntech.com Trampas -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of R A Bennell Sent: Friday, November 10, 2006 3:47 PM To: Mercedes Discussion List Subject: Re: [MBZ] Project to tickle your brains with.. Yes, I saw the post yesterday with the link to Roger Brown's site. I knew about him from my travels on the net relating to old Toyota 4X4s. The idea of using a crank sensor appeals. I just wondered what else I needed. Randy -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Rich Thomas Sent: Friday, November 10, 2006 11:37 AM To: Mercedes Discussion List Subject: Re: [MBZ] Project to tickle your brains with.. You could do an LED and a light sensor with a white mark on the crank, of course that would be affected by whatever goop gets splashed up there, but something to wipe it off as it goes around... --R R A Bennell wrote: What triggers the crank sensor on most new cars? Is there a magnet inbedded in the crank dampener/balancer/pulley (whatever you wish to call it)? IE - If I were to try this route to put a tach in my 76 300D, I assume I would have to attach something to the balancer to trigger the sensor as there would not be anything from the factory. Randy -Original Message- Given the relatively ready supply of junkyard parts, I can't see any reason not to just use them, it's nearly trivial. (As I believe the front crank sensor is already there, at least on a lot of cars. Goes to the diagnostic socket.) Even if you have to install a factory sensor, it has to be easier than flanging up something yourself. And running it all over, and designing circuitry. -- Jim ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED
Re: [MBZ] Project to tickle your brains with..
Sensor on the crankshaft pulley and an LED or LCD display? Would not be hard to make with a simple sensor, chip and display. (Not that I know how to do that yet, but I have been reading about it quite a bit and am going to order a kit to start some PIC programming. This kind of stuff appears to be really simple, only a few dollars worth of parts too). --R Kevin J. Slater wrote: Our 79 240D had a partial cluster replacement from our crushed 82 300D which included replacing the clock with the clock / tach from the 300D's cluster. I know that there are likely parts missing from the 240D engine compartment to drive said tach. How about using an embedded device (like a Basic Stamp or similar) and counting some pulse coming from the alternator and using that to drive the tach input? Would that work? Thoughts? Jim?
Re: [MBZ] Project to tickle your brains with..
Rich Thomas wrote: Sensor on the crankshaft pulley and an LED or LCD display? Would not be hard to make with a simple sensor, chip and display. (Not that I know how to do that yet, but I have been reading about it quite a bit and am going to order a kit to start some PIC programming. This kind of stuff appears to be really simple, only a few dollars worth of parts too). Here's a how-to page for doing it on a VW, using an optical encoder on the injector pump sprocket and a 4-cylinder gasoline engine tach: http://www.4crawler.com/Diesel/CheapTricks/Tachometer/index.shtml You could do something similar on a Mercedes using the crank sprocket, although it'd be a little trickier to mount everything right. Since the crank turns at twice the speed of the camshaft or injector pump, you'd use an encoder wheel with two light and two dark segments, instead of four.
