Decade counter/555 for use as a push button ignition switch

Thread Starter

MATTY B

Joined Jan 26, 2008
49
soren, one last thing, do you happen to have the measurements of the pcb layout so I can verify its size when I print it on my laser printer? If not I can use calipers and check the pin spacing and make sure the scaling is correct but it would be alot easier and possibly more accurate if I just had that measurements ready to go. Im pretty excited, I havent made a PCB since I was in college in my Beginning electronics class so it should be fun to do it again. Thanks again
 

Thread Starter

MATTY B

Joined Jan 26, 2008
49
Success!!! It works perfectly. Im wondering one more thing. Is there a way I can add a little daughter board to this so that I can control the led in the switch Im using? What I was thinking would be to make something so that the single light would flash slow when it is in ACC, faster in IGN and after start was pressed it stays on solid. I have the circuits already to make an led flash so thats not a problem its switching between them that Im trying to figure out. I figured I may need to use another decade counter and just diode the led outputs to a single pin on the clock pin of the decade counter. woth that done I can trigger two flasher circuits on Q0,Q1 and just straight out on Q3. This may work it may not but it sounds logical. If you got an idea on how I can do this my setup will be complete. Thanks so much Soren for this I am forever in your debt
 
Why not just a toggle switch for the ignition, and put the starter button under the accelerator like the 1950 Buick?

How were you planning to unlock the steering wheel? If ya gotta use the key to work the lock, why not just twist it and start like the rest of us? No key and no lock sez "Steal me!".
Hi, new here. just wanted to ask you a question about the 1950 buick. we went to start her today and she didn't start. the lights came on and everything, it just seemed like the switch wasn't catching. i looked underneath the car and couldn't even find where the switch should be. it just looked as if there was nothing there.
i am pretty sure it had one, because i could feel it in my foot when i put my foot on the accelerator to start her up.
she just wont start at all and i am baffled.
could you possible tell me where the switch is and how i could repair it?
thanks.
 

SgtWookie

Joined Jul 17, 2007
22,230
I suggest you try this forum:
http://www.teambuick.com/forums/

Attached is a wiring diagram for a 1950 Buick.

Note the battery at the upper left; down and right is the "cranking motor" or starter, and down and right from that is the "accelerator switch", then down and right from that is the "neutral safety switch".

Make sure the gear shift is fully in "park" or "neutral".
 

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jpanhalt

Joined Jan 18, 2008
11,087
You probably should start your own thread. When you do that, make clear whether you are talking about a starter switch inside the car or something in the engine compartment, such as the starter solenoid, relay, or (least likely)voltage regulator. John
 

Rabster

Joined Mar 14, 2010
10
Hi sorry to drag up an old thread but i have built the main parts of this circuit now however the only IC i can find is a HEF4017BP will this still do the same as the IC spoken about in this thread 4017n

Cheers
Andrew
 

Rabster

Joined Mar 14, 2010
10
ok just put it in the circuit and the outputs seem very intermittent occasionally it runs the way its meant to then all of a sudden its out of sequence very strange

im building it on vero-board as don't have access to etching gear at the moment

just in case im being thick does anyone have that circuit design in vero-board plan???

Cheers
Andrew
 

SgtWookie

Joined Jul 17, 2007
22,230
One of the big reasons for it to be skipping pulses is if you are not using 0.1uF caps to bypass the IC supply pins. Each IC must have a bypass cap.

The other big reason is if you are not using the correct switch. It must be single-pole, double-throw. You cannot use a single-pole single-throw switch with this circuit successfully.
 

Rabster

Joined Mar 14, 2010
10
Ahh ok well i have no 0.1 caps available at the moment, with regards to the input its a simple push to make switch so i was using a SPDT relay

Cheers Andrew
 

SgtWookie

Joined Jul 17, 2007
22,230
That is why you are having problems.

You must use a SPDT pushbutton switch. You cannot use a push-to-make to drive a relay. It won't work.

The "push to make" switch will "bounce", which will cause the relay to "bounce", and you will get multiple triggers on the 4017.

Someone else tried this before, and they had the same problem.

The fix is to use the 0.1uF caps and the proper switch.
 

Rabster

Joined Mar 14, 2010
10
Cheers for that :)

the switch that i will be using is a spdt so i will connect that up tommorow evening see if that makes a difference along with some Capacitors does it need to be 0.01uf ?

as i have a few spare bits over was going to make another one, so looking for a vero board layout just to ensure i have everything correct...

Cheers
Andrew
 

SgtWookie

Joined Jul 17, 2007
22,230
If you want to make it correctly, make the proper board.

I'm not going to do a Veroboard layout for you, nor verify a Veroboard layout if you post it.

The layout that Soeren posted will work, if you etch the board and assemble it correctly with good parts. It really doesn't have adequate protection for overvoltage, and I am not inclined to add it.

It is not so bad if the circuit fails, because you will simply not be able to drive the vehicle; so it is not a safety-related issue. I just don't know why anyone would want to do such a thing.
 

Rabster

Joined Mar 14, 2010
10
Hi
I don’t have the facilities to get a proper board etched up at the moment so i need to build on vero board i wanted to make sure the circuit would do all i wanted it to do before i paid out to have the board etched that was all.
Cheers Andrew
 
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