Pleaseeeeeeeeeeeeeeee help !!

[spark727]

Can anyone help me please, i need a schematic of a car speedometer with a DIGITAL (3 digits) AND LED display (with about 60 led's), what displays simultaneously.


Pleaseeeeeeeeeeeeeeee help !!

 

[akg]

searching this forum will give you a circuit

 

[spark727]

Perfect, no matter circuit or schematic, i am happy and gratefull for either one.

 

[Hero999]

Read the previous post, don't be so bloody lazey.

 

[spark727]

????

What previous report????

please let me know, i am by far not lazy.



As i said, i am gratefull for any help

 

[lord loh.]

At the top, there is a search menu. Click on it and search for speedometers. This topic has been posted on the forum before and members feel it a waste to rewrite an existing book.

If you have any queries that have not been clarified in other posts, post again.

 

[spark727]

NEED help for Digital Speedometer

Hi People,
here is the Speedometer i would like to build, and need your help to it.

I went trough all the postings, and all i could a find is a part of it https://martybugs.net/electronics/speedo.cgi

now i would need the schematic of the LED's, so i could combine the two circiuits together, OR somebody has maybe some better solution, PLEASE uyou are most welcome

but thanks a lot for that posting anyway, its a start.......... thank you

 

[audioguru]

Do you need a circuit to drive the 100 LEDs in a bar graph?
Have you ever seen an LED display outside when the sun is shining? It is difficult to see unless there is a big, ugly shade over it.

 

[spark727]

yes Uncle,
i need a schcematic to drive does "100 LED's", and thats why the speedometer is buid in digital as well.

And if you noticed, in some older cars they even made LCD, where u can see only blck on gray, what is much less efficiant, but used anyway................,
BUT i build already some other devices, and they are realy "a cool" issue, and usefull.
Soonest the car is compleeted, i will post the pictures of the whole dashboard in here, (pictured by day and by night), so will you see the efficiency of the instruments.

hang loose
and thanks

 

[audioguru]

The electronics for turning on 100 LEDs is easy but it takes many ICs.
What do you have as a speed sensor?

 

[spark727]

I don't have any yet, i just have some suggestions, like the one i posted from Martin, and maybe its a very good idea, because magnets have a long live, .............. and i am realy a nuts in matters of Digital, so ANY good suggestion and good function is welcome.

Please shoot, let it out, what do you have in mind ,

thanks uncle

 

[audioguru]

I didn't see Martin's post.
There are two ways to make an accurate speed sensor for your car:
1) Drag your bare foot on the street outside your car and measure the loudness of your screams with a microphone.
2) Drag a heavy piece of iron on the street behind your car and measure the brightness of the sparks with a phototransistor.

First I thought about using a 5th wheel or a windmill driving a generator, but they aren't good.

 

[bloody-orc]

also you could try to find a speedometer that police uses (you know that gun). aim that towards your car and there is a display allredy built on it. you get a perfect result and if you have a policeman sitting beside you you could even give someone ticket for speeding. alsoyou could mesure the speed by reading how fast houses/trees/cars pass you. it's all math. 5th wheel or a block of iron might be better, but i reccon that my ways are a bit cheaper (and easyer).

also you can try google. it has a LOTS AND LOTS!!! circuits that you are searching. try to do AT LEAST SOMETHING YOURSELF MAN!!!

 

[spark727]

i think here is a reasonable idea for the sensor and the circuit , so it maybe changes your mind from the 5th wheel - to.................. ????

and i hope some lights will turn on

BUT: as i said, i am gratefull for any help

thanks guys

 

[spark727]

(P.s. i am googeling since week's, and could not find yet what i want, there is always either or, but but non what i am looking for, AND thats the reason i am here and asking for help )

 

[Oznog]

also you could try to find a speedometer that police uses (you know that gun). aim that towards your car and there is a display allredy built on it. you get a perfect result and if you have a policeman sitting beside you you could even give someone ticket for speeding. alsoyou could mesure the speed by reading how fast houses/trees/cars pass you. it's all math. 5th wheel or a block of iron might be better, but i reccon that my ways are a bit cheaper (and easyer).

You just go down the highway with a stopwatch and count mile markers. 60 sec apart=60mph. If you have an odometer reading- which is trivial to add if you have used a microcontroller- then you can just see what it thinks 1 mi is versus the mile markers and tweak it appropriately.

 

[audioguru]

You are not going to make a bar graph with about 100 LEDs with that very fuzzy schematic of a 7-segment display circuit. You need an LM2907 or LM2917 tachometer IC and a bunch of LM3914 bar-graph driver ICs.

 

[musthave]

here is a circuit of a tach but can be converted for speedo app there is 7 pages so if that what your looking for let me know and will send them to you by email only.