Thanks mate. I guess it's going to take a lot longer than I originally thought.

 

@Cold Turkey,

Its your call as to who you would believe, depending on what "occasional overcurrent" really means.

Though the warning in the data sheet would probably prevent me from using such design in a formal product, being a hobbyist you are having greater freedom to muddle the line a bit. Using such device as a window traveling limit switch does fit the occasional overcurrent criteria.

The first principle is that doing so must in no way endanger the user or product in any way.

The use of the PTC is so simple and effective that it replaces quite a few limit switches and simplified the whole design, not to mention the problem of installing mechanically those switches on the doors. The fact that the design appears on the manufacturer's magazine did mean quite a few people knowledgeable in the specific of these PTCs have looked at the design and given their unofficial approval(or at least no objection) for using them in this manner.

The FAQ on the RayChem Polyfuse website did mention in order to get UL approval, the PTC device must function without problem for at least 6,000 cycles. The added comment that the fuse will always fused in the open state would also bring confidence in using them.

In view of all these, I would say the original circuit is probably functional without any big problem. You would just need to place an additional fuse or PTC with twice the current rating in series as a backup in the master +12V supply to your circuit and you will be OK.

 

Mate, thanks so much for the extra effort and research.

Knowing that they are going to run close to 6000 cycles is awesome. I'll try and put some type of screw down terminal block for them so they can be easily changed in the future. I'll add some extra fuses in as well just in case.

I guess if worst comes to worst, I rebuild the thing in a couple of years time.

While I've got you guys on the thread though, do you see any solution to my original dilemma? A bit of expert scope on it would be awesome.

Cheers.

 

Knowing that they are going to run close to 6000 cycles is awesome.

That's not what it meant. You can probably expect quite a lot more cycles from these fuses, over 10,000 cycles would not be unreasonable.

 

Yeah mate, I understand. I just thought that if they do run 4 to 10 thousand cycles and they work perfectly for the job then having the ability to swap them out and a bunch of spares would be good.

 

I can try but it may be even more confusing

Outputs from actuator - A1 and A2

Initial state - (A1) nothing, (A2) nothing

Button pressed - Lock Button

When pressed - A1 becomes positive, A2 becomes negative. (momentary)

When pressed again - A1 becomes positive, A2 becomes negative. (momentary)

----------------

Button pressed - Unlock Button

When pressed - A2 becomes positive, A1 becomes negative. (momentary)

When pressed again - A2 becomes positive, A1 becomes negative. (momentary)

Hope that makes sense of it.

I guess my confusion is that the listed states and transitions both do the same thing: A2 is +12V, A1 is GND.

Is that a typo?

 

On lock A1 is 12+ and A2 is GND

On Unlock A2 is 12+ and A1 is GND

Sorry for any confusion

 

On lock A1 is 12+ and A2 is GND

On Unlock A2 is 12+ and A1 is GND

Sorry for any confusion

What is the difference between pressing the button once or twice?

Do the locks currently function?

I am reading this as you already have it set up and working, but now are trying to add a remote. Did I get confused?

 

The locks do function correctly, I haven't got this one working but it's the third one I would have installed so I know what it's going to do.

There is no difference to their states if you press the same button multiple times. The difference is between lock and unlock.

I'm not trying to add a remote. What I'm trying to do is add a circuit that can identify the second press of the lock button and the second press of the unlock button within a two second period.

If there is a second press within that time period then I want it to either roll up or down the windows.

I'm just reading back, your first post where you ask if there was a typo with my transitions... I'm looking at it and I don't think there is. A1 and A2 show different states for unlock and lock but show the same state if (for example) lock is pressed once and then pressed again. I probably just confused things by adding the same state twice for the second press.

You guys are a lot more switched on with this gear than I am (no pun intended) I'm more than happy to try and explain it again but I may be missing something all together.

 

I have quickly put together a workable solution for your case.

There are finer details that still need to be ironed out like the power supply etc.. but does the circuit performs as that you wanted in the first place?

Circuit operation(please ignors R8, its there for simulation purposes)

0. circuit get its signals by connecting the two Car_Lock lines to A1 and A2 of existing car lock

1. the two opto-couplers 4N25 convert the bi-polar car lock activation voltage into uni-polar pulses, "LOCK" and "UNLOCK"

2. these pulse are used as clocking signal to the two D Type FlipFlop(F/F) U4/5.

3. these pulses are also combined into a single pulse Via D1 & D2 to trigger 555 monostable timer, with timing determines by R6/C2, currently about 2 seconds

4. the triggered 555 has an output of HIGH and this is fed to the D input of the F/F

5. when there is no input lock/unlock pulse, 555 timer output is LOW, so the level of F/F "D" input is also LOW

6. any incoming lock/unlock pulse would clock the F/F and triggers the 555

7. however, because the 555 has held the reset input of both F/F active, the initial clocking on the CLK of F/F has no effect. F/F now come out of reset, waiting for clocking

8. "D" inputs of both flip-flop then become HIGH for a period of 2 seconds, via the 555 output. This has no effect on the F/F output as there isn't any clocking involved, so both F/F output stays LOW

9. if there is another lock/unlock pulse arrival, it will not affect the already triggered 555 but this time the level of "D"(which is now HIGH) will be clocked into the Q output, giving a HIGH

10. when the lock/unlock pulse ends, both FF are reset via the U9/10/C4 connection, thus ending the output

11. if pulses of opposite polarity arrives within the 2 second period, it will also produce an output but keeping the door in the previous state(because the two operation negates the effect) so enable user to wind up/down the window without affecting the status of the door

 

Mate you're a legend. That's exactly what I was after, I can see now why I didn't have a hope in working it out.

Thank you so much.

Is that ready to rock and roll or are there other things I should be working out to?

 

Is that ready to rock and roll or are there other things I should be working out to?

There are a couple of issues.

1. As the +12V is coming from the car battery, it would have a lot of nasty pulses riding on it when the engine is running. The voltage on the battery can also rise to 14.8V. This voltage is too high for comfort for LM555 or CD40106B. I would suggest using a common voltage regulator, like 7809 or 7808. The circuit design have no issues with 9V or 8V supply voltage and does not need any modification.

The TVS diode is there for protection and I don't have a specific part number for you to get hold of and it also depends on the component supplier near where you live. Other forum members can surely suggest a suitable one without problem.

2. The HIGH signal on the FlipFlop output is a voltage equals to supply voltage but with very little current drive capability and certainly cannot drive the window motor circuit. You need an interface between the signal and the final drive, most likely using relays. The interface is simple. However, you might have difficulty getting a 9V-coil relay but that can be solved by using a 5V relay with a series resistor in the coil to make it 9V. The easiest drive is to use N-CH Mosfet and they are cheap. Or you can use NPN darlington transistor instead.

3. Make sure you order CD4013B and CD40106B as the HC4013 or HCT4013 would not work at that voltage.

4. On ordering, make sure that you know exactly which IC/semiconductor package are you getting as part comes in many different packaging, with only a slight different in their numbering.

 

There are a couple of issues.

1. As the +12V is coming from the car battery, it would have a lot of nasty pulses riding on it when the engine is running. The voltage on the battery can also rise to 14.8V. This voltage is too high for comfort for LM555 or CD40106B. I would suggest using a common voltage regulator, like 7809 or 7808. The circuit design have no issues with 9V or 8V supply voltage and does not need any modification.

The TVS diode is there for protection and I don't have a specific part number for you to get hold of and it also depends on the component supplier near where you live. Other forum members can surely suggest a suitable one without problem.

2. The HIGH signal on the FlipFlop output is a voltage equals to supply voltage but with very little current drive capability and certainly cannot drive the window motor circuit. You need an interface between the signal and the final drive, most likely using relays. The interface is simple. However, you might have difficulty getting a 9V-coil relay but that can be solved by using a 5V relay with a series resistor in the coil to make it 9V. The easiest drive is to use N-CH Mosfet and they are cheap. Or you can use NPN darlington transistor instead.

3. Make sure you order CD4013B and CD40106B as the HC4013 or HCT4013 would not work at that voltage.

4. On ordering, make sure that you know exactly which IC/semiconductor package are you getting as part comes in many different packaging, with only a slight different in their numbering.

Is this free hand or paint or photoshop.

 

Is this free hand or paint or photoshop.

Is this a trick question?

 

Is this a trick question?

where's the trick in it.
I want to compliment. If it is paint, I give u a gold star

 

where's the trick in it.
I want to compliment. If it is pain, I give u a gold star

The Trick , or at least what I use when making semi-straight lines and handwriting on drawings.

 

AAAAAAAAAAH!!.. a tablet.

I got to get me one of those

 

Awesome, cheers mate. I'd probably go for a darlington instead of the relay seeing as the power to drive the windows will be provided by the other circuit already and it doesn't need to switch a huge load.

Thanks again.