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**DONOTDELETE**
12-24-2000, 08:35 PM
anyone know the exact specs on the harness pins for the 1990 240 HUD unit? the control unit which takes in the speed signal is actually in teh digital dash which i dont have so i'm trying to come up with a custom solution but i dont know the details and i only figured out how to make the thing light up. the FSM is no help at all.

i'm trying to figure out a way to make the HUD unit work with the analog gauge and i dont want to go putting the whole digital cluster behind the analog one. i could just find a digital dash and take the control unit out of it but that'd be too easy (and a smart thing to do but i'm not into that) http://www.freshalloy.com/

redlyne
12-25-2000, 02:40 PM
I thought that the HUD worked was that there was only one readout (in the dash) and that the HUD just focused that image on the windshield. If I'm wrong, which is entirely possible, then it could be setup like the analog speedo. in that the signal wire goes to the speedo first, then to the ecu. If that's the case, then it would be a simple matter of just splicing off of the speedo wire. And finally, I don't think it'll work at all without the LCD driver, which would be in the control module. And you would need the windshield from an HUD car, too. (or is an adhesive reflector?) Merry Christmas and good luck.


Sean

**DONOTDELETE**
12-25-2000, 10:32 PM
nope, HUD's a separate unit. i can use adhesive tint on the windshield, mine's a bit warped but i'm not ready to part with it just yet. i'm not sure what order the signal reaches everything in is but it doesnt matter in this case. the control unit for the HUD is what i'm trying to make. hence i need the specs for what the original HUD control unit's output is like.

<BLOCKQUOTE><font size="1" face="Verdana, Arial[/img]quote:</font><HR>Originally posted by redlyne:
I thought that the HUD worked was that there was only one readout (in the dash) and that the HUD just focused that image on the windshield. If I'm wrong, which is entirely possible, then it could be setup like the analog speedo. in that the signal wire goes to the speedo first, then to the ecu. If that's the case, then it would be a simple matter of just splicing off of the speedo wire. And finally, I don't think it'll work at all without the LCD driver, which would be in the control module. And you would need the windshield from an HUD car, too. (or is an adhesive reflector?) Merry Christmas and good luck.


Sean<HR></BLOCKQUOTE>

redlyne
12-26-2000, 12:41 AM
This ended up being kinda long, so bear with me.

I understand where you're coming from, but I doubt it's possible to "make" a control module for it. From what I can see, the HUD unit is basically a backlit LCD. Traditionally, these are run by an outside driver, or controller. All this is, is a chip that takes an input signal, in this case it would be pulses generated by the motion of the speedometer cable. This chip then makes the LCD unit display it's translation of the signal as predifined by whoever programmed the driver, in the form of numbers. (whew!) So if the speed sensor is putting out X, then the driver will make the HUD say 75mph. Y equals 100mph. F equals 55mph, and so on. These are figurative but I think you get the point. So unless you know what the speed sensor is saying, and what the HUD needs to hear to display right, AND you know how to program PROMs, then it would probably be easier to just get the control module. Then again, if you have to buy the whole digital cluster to get it, it might be cheaper to see if you can get someone who can do all that stuff. And just curious, how much did that HUD cost you? Might wanna do that one day. Once again, good luck.


Sean

P.S. I have no hard evidence that this is how Nissan did it. This is just the way nearly all LCD's work.




[This message has been edited by redlyne (edited 12-26-2000).]

**DONOTDELETE**
12-28-2000, 05:13 PM
yes, i know. except it's not a speedometer cable but a pulse signal from the sensor. what i want to know is the pinout specs of the LED unit. does anybody know the input specs on this thing? i dont want to have to go through the printed circuit, it's a pain in the ass. it's not a direct input from the decoder, there are 6 free pints in the 8 pin harness, 2 of them being a light power input. the largest number 6 pins can represent is 64, where'as the HUD can display stuff up to over a 110 at least and goes in increments of one from what i've heard. once i know how to control the HUD unit, i'll either put together a logic circuit to do it or program a PIC chip or something.

the HUD unit itself cost me $25, i bought it from someone i know.

<BLOCKQUOTE><font size="1" face="Verdana, Arial[/img]quote:</font><HR>Originally posted by redlyne:
This ended up being kinda long, so bear with me.

I understand where you're coming from, but I doubt it's possible to "make" a control module for it. From what I can see, the HUD unit is basically a backlit LCD. Traditionally, these are run by an outside driver, or controller. All this is, is a chip that takes an input signal, in this case it would be pulses generated by the motion of the speedometer cable. This chip then makes the LCD unit display it's translation of the signal as predifined by whoever programmed the driver, in the form of numbers. (whew!) So if the speed sensor is putting out X, then the driver will make the HUD say 75mph. Y equals 100mph. F equals 55mph, and so on. These are figurative but I think you get the point. So unless you know what the speed sensor is saying, and what the HUD needs to hear to display right, AND you know how to program PROMs, then it would probably be easier to just get the control module. Then again, if you have to buy the whole digital cluster to get it, it might be cheaper to see if you can get someone who can do all that stuff. And just curious, how much did that HUD cost you? Might wanna do that one day. Once again, good luck.


Sean

P.S. I have no hard evidence that this is how Nissan did it. This is just the way nearly all LCD's work.


[This message has been edited by redlyne (edited 12-26-2000).]<HR></BLOCKQUOTE>