speedometer, tachometer etc.. with air core

hello I was just looking for a speedometer and tachometer for my almost finished race sim.
but the prices for ready kits are very expensive, so i was surfing google for a diy solution.
and yes i did see the servo controlled speedometer from tronicgr,
but it seems that it jumps a little with deceleration and i already have a couple of aire core's from
car dashboards.

so this is what i found so far (in language i understand : ).
http://www.mikesflightdeck.com/diy_aircore_instruments.htm

this is the part that intriged me

so after a lot of typing my question is can i use a amc1.5 from tronicgr to drive air core's.
because i have 2 amc1.5 and 2 dsmh1.2 left.(because of ordered from 2 different etching services).

regards wim post.

Hi wimpo,

I've seen mikesflightdeck article about air-cores before, but not much information is given (except if you buy his books...!!@$#@^)

The difficult is to drive the air-core gauges is the need AC PWM drivers. I have found some drivers that are used in cars for this purpose: CS4122 (Triple Air−Core Gauge Driver with Serial Input Bus)

You can interface this driver easily with any microcontroller (and with my AMC1.5) but its very difficult to source them. If you, or anyone else, could find a nice source for this chip I could re-program the AMC's firmware to drive it!!!! And we could then be able to use ready made air-core instrument clusters from real cars!!!!

Regards, Thanos

but i understand from his page that you can also drive an air core with a micro controller,
by controlling the 2 core's with pwm and a h-bridge.
i don,t know if you can do something with this, but it is the HEX file from the aircore.

http://www.mikesflightdeck.com/hexDL/AIRCORE1.HEX







this guy has done it like this to i guess.

http://www.youtube.com/watch?v=kt58x0zJ5gg

ok i found something else now.

i took my dashboard appart because i didn't have a tachometer, so i will have to replace it or build one.

here is what i found, the speedometer in my case isn,t air core driven but it has metal disk in it with a permanent magnet.
more info here:
sorry for the bad english i had it translated with google.
http://translate.google.com/transla...e1500.nl/id142.htm&hl=nl&ie=UTF-8&sl=nl&tl=en

this meens that a rotating cable is connected from the car to the speedometer, how faster the cable rotates the more degrees the speedometer turns.
i tested it with a drilling machine and the speedometer turned 45 degrees so it does work.
the little spring in the front make's it go to zero (smoothly) when the cable stops turning.


so here is a theorie.
if you could extract the acceleration speed from a game (Pitch i guess)
and make a smal but fast electric motor turn with the speed of the car/airplane,
and connect the motor to the speedometer you should get results.
the only downside is the noise i think.

second theorie replace everething but the spring :?
and use a freewheel electric motor of some sort so when the current is cut of, it turns back to zero (smoothly).

about the air core i'm still searching for other options for driving them,
because the air core drivers are really difficult to find.

so a car send's two different ellectric currents with a CS4122 to both coils to from air core hmmm... :bulboff: i wonder where the driver would be.
I have two air core's by the way 1 out of the temperature meter and 1 out of the fuel indicator.
i asked arround and the fuell indicator uses a potentiometer in the tank.

Aircore drivers are cool, as you can drive real cockpit clusters directly. But before I would use such permanent magnet things (just imagine the whining sounds of the motor rpms to drive the disk :lol: ), I rather would use servo motors, like Thanos did.

diy-analog-servo-car-instruments-t890.html

Regards
Christian

ok i think this will work then, if you want to go for the most silent aproach.


+

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:happy:

ok i found a pdf regarding about driving air core's with a microprocessor.

here's the file