New to the site- Question about making a paddle shifter for my car

SgtWookie

Joined Jul 17, 2007
22,230
The switches are on the far left of the schematic. They are of the SPDT type (Single Pole, Double Throw) - and they should be spring-loaded to one side.

The schematic is a bit hard to read; you will have to look at it closely to find junctions.

For example, look at Z1 pin 3; it's output goes to both Z4C pin 7 and Z5A pin 1; that's an easy junction to spot. What's not so obvious is the connections from Z1 Pin 2 - yes, the Z4D pin 9 connection is easy, but the junction connecting it to R1 and Z5A pin 2 is not; there is just a VERY small white dot at the junction.
 

beenthere

Joined Apr 20, 2004
15,819
Sorry for the poor quality of the schematic in the area of the connection dots. I still use a DOS CAD program, and have to open it in another to allow saving the schematic as an image. The second CAD program diddled the dots (actually pads) from a diameter of 60 mills way smaller, and increased the hole size from 2 mills up to more like 8.
 

Ron H

Joined Apr 14, 2005
7,063
Sorry for the poor quality of the schematic in the area of the connection dots. I still use a DOS CAD program, and have to open it in another to allow saving the schematic as an image. The second CAD program diddled the dots (actually pads) from a diameter of 60 mills way smaller, and increased the hole size from 2 mills up to more like 8.
There is only one confusing connection that I see. You should avoid connections at crossings. See below.
 

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Ron H

Joined Apr 14, 2005
7,063
Nope, that's a legitimate connection.

I may have to see if I can't remove some ambiguity from the schematic.
That's my point. I was taught from the time I was in diapers that you never make a cross where you want a connection. It is too easy to misinterpret it. You should always jog one of the wires, as in the no cross drawing.
 

beenthere

Joined Apr 20, 2004
15,819
For hand drawings, the loop over the crossing trace is certainly better. In the vast majority of schematics from outfits as professional as they come, the connecting dot is the accepted practice. In a CAD program, doing all those semicircular arcs is just way too much work. Plus the schematic capture app indicates connector dots.

Anyway, I increased the size of the pads for the connecting dots, so it's easier to interpret.
 

Ron H

Joined Apr 14, 2005
7,063
For hand drawings, the loop over the crossing trace is certainly better. In the vast majority of schematics from outfits as professional as they come, the connecting dot is the accepted practice. In a CAD program, doing all those semicircular arcs is just way too much work. Plus the schematic capture app indicates connector dots.

Anyway, I increased the size of the pads for the connecting dots, so it's easier to interpret.
By golly, you're stubborn. :D
What's wrong with offsetting one of the wires? That way, if you forget the dot entirely, the schematic is still correct.
 

beenthere

Joined Apr 20, 2004
15,819
Sheer habit. Done it that way for 30 + years. And my dots straight out of the CAD program are nice and unambiguous. But I do tend to jump over crossing wires drawing by hand.
 

Ron H

Joined Apr 14, 2005
7,063
Sheer habit. Done it that way for 30 + years. And my dots straight out of the CAD program are nice and unambiguous. But I do tend to jump over crossing wires drawing by hand.
OK, I give up.
My habit began when I started drawing schematics as a young engineer (1966). We gave them to a draftsman to clean them up. He/she sat at a drafting table with pencil and paper and a drafting machine. You can probably understand why we were told on no uncertain terms to never cross wires where we intended to have a connection. The draftsmen followed the same rule.
 

beenthere

Joined Apr 20, 2004
15,819
I plead not guilty to being an EE. But the prints to my old Univac computers used connector dots and did not jump non-contacting wires/traces. Got into bad habits from the beginning (1967).

Ha! I just dug out some of my old Heathkit schematics. They use connection dots and cross non-contacting traces with impunity. See? A lifetime of bad influence.
 

Thread Starter

dmc0162

Joined Dec 13, 2007
51
Thanks for the updated schematics guys!

I have one more question though...

How hard would it be to make this circuit work with a 7-segment display to show what gear I am in?
 

Ron H

Joined Apr 14, 2005
7,063
I plead not guilty to being an EE. But the prints to my old Univac computers used connector dots and did not jump non-contacting wires/traces. Got into bad habits from the beginning (1967).

Ha! I just dug out some of my old Heathkit schematics. They use connection dots and cross non-contacting traces with impunity. See? A lifetime of bad influence.
I regularly cross non-contacting traces without a loop. I'm talking about 4-wire junctions.

 

Thread Starter

dmc0162

Joined Dec 13, 2007
51
Also, one more thing. In the schematic you made for me, it almost looks like the circuit works by sending a GROUND to the solenoids. The solenoids are self grounded inside the transmission, I need to send a +12v source to the solenoids to shift them. Is that how this schematic is designed?
 

beenthere

Joined Apr 20, 2004
15,819
No. The relay contacts are not shown with any connection to the outside. They are just uncommitted contacts.

Adding a 7 segment decoder would give the display, as would several LED's. With LED's, you could also indicate park and neutral.

Please do not forget that there is no RPM lockout to prevent you from downshifting at an engine speed that will cause mechanical disassembly.
 

Thread Starter

dmc0162

Joined Dec 13, 2007
51
No. The relay contacts are not shown with any connection to the outside. They are just uncommitted contacts.

Adding a 7 segment decoder would give the display, as would several LED's. With LED's, you could also indicate park and neutral.

Please do not forget that there is no RPM lockout to prevent you from downshifting at an engine speed that will cause mechanical disassembly.
How difficult is it to make an RPM lockout? Say I wanted to make a 5000 RPM threshold where the circuit would not shift unless it was below that. Should I just measure the volts from the RPM signal at 5000 RPMs? Then how could I make something that would not DOWN shift unless it below that voltage?

Also, how do I go about adding in this 7 segment decoder? What terminals would go where?
 

beenthere

Joined Apr 20, 2004
15,819
Don't know diddly about your car. The tach signal is more likely to be a frequency, though. You'd have to be careful not to mess with the ECU getting at it.

Adding the lockout takes more logic. Hard to say just how much. Possibly using a frequency to voltage converter and a comparator, plus one additional gate (I think there's one left over to use). So, two devices plus some analog components, like resistors and at least one capacitor.

The decoder/driver would take the four output pins from the CD40192 (2 not on the schematic) as inputs. Look up a CD4511 datasheet.
 

Ron H

Joined Apr 14, 2005
7,063
How difficult is it to make an RPM lockout? Say I wanted to make a 5000 RPM threshold where the circuit would not shift unless it was below that. Should I just measure the volts from the RPM signal at 5000 RPMs? Then how could I make something that would not DOWN shift unless it below that voltage?

Also, how do I go about adding in this 7 segment decoder? What terminals would go where?
I guess a 7 segment decoder might add some bling, but your tachometer (or your ears) is really all you need.:D
 

Thread Starter

dmc0162

Joined Dec 13, 2007
51
Ok, so the RPM lockout is a little to much for me. I am not to worried about downshifting at the wrong time because I have been running my own little simple manual shift box in the car for a few months now with no accidental shifts.

I would really like to try the idea of having the 7 segment display work. Would anyone be able to add to my current schematic the decoder and the display and what terminals go where? I would really appreciate that.
 

Thread Starter

dmc0162

Joined Dec 13, 2007
51
One more question, would using this IC (cd40110BE):

http://www.mouser.com/search/ProductDetail.aspx?R=CD40110BEvirtualkey59500000virtualkey595-CD40110BE

instead of the CD40192 be helpful? It looks like this one has an up/down counter with outputs for a 7 segment display. Am I correct? I am probably wrong, just wondering thats all! thanks

I am wondering this because I would really like to add the 7 segment display to my paddle shifter. Would it be easier to just use the 40192 with a separate chip for the display?
 
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