Would it be possible to add a gauge sweep at startup?
04-01-07, 11:32 AM
#1
Would it be possible to add a gauge sweep at startup?
Like how the new ISx50s startup.
http://www.youtube.com/watch?v=C_S3MCOgdrU
video for reference.
It would be so cool to have my GS do this.
http://www.youtube.com/watch?v=C_S3MCOgdrU
video for reference.
It would be so cool to have my GS do this.
04-01-07, 11:51 AM
#2
Lexus Test Driver
It's possible-- you'd need to be well versed in circuitry and be able to read and interpret a very detailed schematic-- Clusters are packed with electronics that are fairly simple but there is a lot there in one small space--
In a nutshell, you'd need to determine the operational voltage and mA of the tach and speedo-- I wouldn't even bother trying to do the gas gauge, temp gauge, and volt gauge, and oil pressure-- that's a lot to mess with-
Once you determine this voltage and current parameter of both -- you'd need a time delay like a flasher, but that only flashes once for a specific amt. of time-- It could get even easier than that if you just triggered the sweep relay with the start wire signal-- so the gauges would sweep while the key is in the full "start" position -- just a second or so-- That is by far the easiest way I can think of--
Then the relay being triggered by the start wire signal would send the voltage to each gauge with the appropriate volt/amp they need to sweep to full reading-- The trick is if they are different operation parameters, they'll need individual circuitry to step up/down the voltage accordingly-- You'd still use a single relay, but the differnces would determine whether you'd just connect boch to the same pole (spst) on the relay operating from the same circuit or two separate poles (dpst) -- The single throw relay is fine as this is just an on/off signal being sent--
Speculation only--
This could all be simpler if you find that the signal the gauges operate on are both 12v, but it's very doubtful that's the case--
The variable signal may sweep from 1v to 5v on the speedo/tach, or 0.5v to 2.5v-- I really don't know--
The signal also may be serial -- operating on signal speed pulse vs. using voltage--
Serial is a whole nother animal-- but there will still be somewhere where the signal is converted to voltage on a varying scale-- that's where you'd need to tap into regardless of whether the signal is serial or voltage--
Also, the tach may be serial or pulse generated, and the speed could be voltage-- but probably both are pulse speed signal generated-\
Test it
Pull the cluster and probe the tach and speedo plugs once you determine where they are-- and find what the signal is-- AC? DC? -- voltage range- amperage range-- that will be a very good start--
You'll need to rev the engine to 5k or better to get the full tach signal range- really redline would be better-- also -- to speculate-- find the signal level at 1k, 2k, 3k, 4k, 5k, and determine if the trend of change is linear-- you'll then know what signal level it is at 6k, 7k, 8k -- so you'll be able to make the tach sweep it's full range-- (mine is 8k on the SC I think)--
Good luck!
Very cool idea and a cool project-
In a nutshell, you'd need to determine the operational voltage and mA of the tach and speedo-- I wouldn't even bother trying to do the gas gauge, temp gauge, and volt gauge, and oil pressure-- that's a lot to mess with-
Once you determine this voltage and current parameter of both -- you'd need a time delay like a flasher, but that only flashes once for a specific amt. of time-- It could get even easier than that if you just triggered the sweep relay with the start wire signal-- so the gauges would sweep while the key is in the full "start" position -- just a second or so-- That is by far the easiest way I can think of--
Then the relay being triggered by the start wire signal would send the voltage to each gauge with the appropriate volt/amp they need to sweep to full reading-- The trick is if they are different operation parameters, they'll need individual circuitry to step up/down the voltage accordingly-- You'd still use a single relay, but the differnces would determine whether you'd just connect boch to the same pole (spst) on the relay operating from the same circuit or two separate poles (dpst) -- The single throw relay is fine as this is just an on/off signal being sent--
Speculation only--
This could all be simpler if you find that the signal the gauges operate on are both 12v, but it's very doubtful that's the case--
The variable signal may sweep from 1v to 5v on the speedo/tach, or 0.5v to 2.5v-- I really don't know--
The signal also may be serial -- operating on signal speed pulse vs. using voltage--
Serial is a whole nother animal-- but there will still be somewhere where the signal is converted to voltage on a varying scale-- that's where you'd need to tap into regardless of whether the signal is serial or voltage--
Also, the tach may be serial or pulse generated, and the speed could be voltage-- but probably both are pulse speed signal generated-\
Test it
Pull the cluster and probe the tach and speedo plugs once you determine where they are-- and find what the signal is-- AC? DC? -- voltage range- amperage range-- that will be a very good start--
You'll need to rev the engine to 5k or better to get the full tach signal range- really redline would be better-- also -- to speculate-- find the signal level at 1k, 2k, 3k, 4k, 5k, and determine if the trend of change is linear-- you'll then know what signal level it is at 6k, 7k, 8k -- so you'll be able to make the tach sweep it's full range-- (mine is 8k on the SC I think)--
Good luck!
Very cool idea and a cool project-
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