Gear Indicator.(need help to build one)

[zx16v]

Hello all.

I'm new here and my understanding in electronics/programming is zero!.(also sorry about my English)

I need help with building a gear indicator to be install in my car with a seven segment display that show the 1-5 /R gears.

The idea is when I shift a gear I will see the number of the gear that im using on the seven segment display until I will shift to another gear.

for example: im driving in second gear...I see the number 2 on the display until I will shift the gear to third gear and than I will see the number 3 on the display.

Because my understanding is very poor in electronics I was thinking about a simple board with six microswitches,1-5 gears and "R" for the reveres gear.each switch will show a number when I press it...but..the number will remain until another microswitch is press.

Any help with this idea will be great!!!

Thank you very much!

Guy.

 

[Nigel Goodwin]

A simple way is to use a PIC, which is a small programmable 'computer' on a chip - you could program it to do what you want, and it would be a one-chip solution.

 

[zx16v]

Thanks for your replay,

Because of my ZERO understanding in electronics i guess that even the simple way to make it for me it will be too complicate to make this chip or any other circuit,do u know if there are kits like that to buy?

Thanks
Guy.

 

[zx16v]

If someone can make for me this circuit it will be GREAT!

Thanks
Guy.

 

[Roff]

If you don't know how to program a PIC, here is a modification of a circuit I designed for a guy who wanted 0-6. As shown below, it will indicate 0-5. You can change 0 (reverse) to some other character very simply.
You will have to come up with a switch closure for each gear. If you can't do it mechanically (microswitches), it could possibly be done with magnetic sensing (Hall effect devices).

 

[zx16v]

Thank you sir for the schema.

Guy.

 

[tunedwolf]

an old analog joystick pot control to do the sensing might be easier to mechanically couple to the gear shift lever, just a thought...

 

[RODALCO]

Don't forget that reed switches may be an option too.

 

[zx16v]

Hi guys...thanks for your replays..the problem is that i can't do anything with this info because i dont know anything in electronics,
im looking for someone with time and good weal to build for me this circuit.(if its not expensive..i will pay for it)

Thank you very much!!

Guy.

 

[Roff]

Hi guys...thanks for your replays..the problem is that i can't do anything with this info because i dont know anything in electronics,
im looking for someone with time and good weal to build for me this circuit.(if its not expensive..i will pay for it)

Thank you very much!!

Guy.

As I pointed out in my PM, you really need some local help. How about asking for help from a college engineering student?

 

[zx16v]

As I pointed out in my PM, you really need some local help. How about asking for help from a college engineering student?

Thank you sir for your B I G help with my first circuit,its working GREAT

 

[Roff]

In response to some requests by PM from zx16v, and another PM from yassirau, I am posting another version of the gear indicator. It is far from being a minimum-hardware design, so don't rag on me about the large number of diodes! It avoids the need to learn to program a PIC, and, for those who may not have easy access to components, uses a minimum of different component types.
This design uses a common-cathode display, and has indications for 0 (reverse?) through 5, and uses "-" to indicate neutral. The "0" can be changed to some other symbol by changing the connections of a few diodes.

 

[Nigel Goodwin]

No problem Ron, it's simply a hardwired ROM, which is what a PIC solution would be simulating.

 

[zx16v]

In response to some requests by PM from zx16v, and another PM from yassirau, I am posting another version of the gear indicator. It is far from being a minimum-hardware design, so don't rag on me about the large number of diodes! It avoids the need to learn to program a PIC, and, for those who may not have easy access to components, uses a minimum of different component types.
This design uses a common-cathode display, and has indications for 0 (reverse?) through 5, and uses "-" to indicate neutral. The "0" can be changed to some other symbol by changing the connections of a few diodes.

Great, i will give it a try and let u know.

Thank you sir!

 

[Sherrif]

help to connect 7 segment display into car

I am building a 7 segment display circuit, for my car. It will display what gear I am in (1-5 + reverse). I have a schematic for the circuit, but i would like to know how i would connect the circuit to the gearbox so it can work.

 

[Diver300]

Is it a manual or automatic box?

If it is an auto, do you want to know what position the selector is in or what gear it is in?

If it's a manual box, is it a standard H pattern lever?

 

[JayTee66]

Also Planning on making a selected gear display unit for a friends old 1976 austin mini, obviously i need an input for 1st, 2nd, 3rd, 4th, Reverse and neutral. the problem is not modifying a wiring diagram to fit but on choosing the input from the gearbox end... still puzzling me (any thoughts) ??

 

[3v0]

It would be cool to do it with two (optical) tach's. Have one count engine RPM and the other drive shaft RPM. You could easily calculate what gear you were in and you would have a digital tach and spedo if you wanted them too.

3v0

 

[Diver300]

Would the 1976 mini have the newer arrangement with the gear lever that is nearly vertical in neutral, or the older one where the bottom of the lever is further forward, nearly at the bulkhead?

You can, as 3v0 suggests, measure engine and road revs, but you need to pick up speed and direction from somewhere. I suppose a quadrature sensor around the speedo cable would give you that.

One problem is that it won't work at low speeds, and if you press the clutch while in top and come to a halt the indicator will show 4, 3, 2, 1, N without you moving the gear lever. It will also show neutral while stationary with the clutch pressed.

Otherwise, you need to detect the linkage position. A few switches operated by the mechanism should do. That was why I was asking about the gear lever. The newer ones have a rod under the car that goes forwards and backwards for the forward and back motion of the lever, and the rod rotates for the sideways motion of the lever.

Microswitches, Optical or Hall effect switches would do. The biggest problem is making sure that you mount them on something that moves with the engine as the engine moves on its flexible mounts.

I fitted a reversing light to a Reliant that came on when reverse was selected, so it was a gear position indicator of sorts. On that car, the top could be got off the gearbox without significant dismantling, and the selector forks could be seen. Each had a 1/4" grub screw to hold it onto its shaft. I fitted a nylon screw into the spare internal thread above the grub screw for reverse. The nylon screw was drilled and fitted with a magnet.

In the top of the gearbox I fitted a Hall-effect sensor, activated when the magnet and the reverse fork moved into the reverse position. There were two transistors to amplify the output of the switch to power the reversing lights.

You could do something like that. The advantage of going inside the gearbox is that there is no relative movement other than the gear selection. However, on a Mini, that is significant job just to get there.

Also, gearbox oil has so much metal in it that it conducts electricity. Certainly when the residue settles out it conducts, so I had to encapsulate the electronics. As all the electronics were in the removable top of the gearbox, that was quite easy.

(And before anybody asks, there wasn't a provision for a reversing light switch on that car.)

 

[3v0]

I am guilty of a couple of things here and let me point out I am being a bit of a smart ars.

The subject is rather uninteresting. I opened the thread to see why it had as many posts as it did. Once I opened the thread I only read the the last two posts.

Then I posted about a device that would be useful to me. All bad.

Having said that:

Anyone who drives a stick knows what gear he is in. If not one can figure that out from the stick position.

With the two tach method one could monitor clutch slip. It would let my wife know when she was riding the clutch (I never do that) or when she needed to shift based on RMP. It could also give a heads up on when the clutch needed adjusting or replacement.

3v0