Help with Capacitors

[sinkoman]

I'm constructing a simple device that, basically, shows how many times a button has been pressed.

It consists of three LEDs and a Normally On/Off switch (the kind that springs back up, so you have to hold it down to keep it on/off, depending no which contacts you're using). Each time the switch is depressed and released, an LED lights up. Press the switch twice, and two of the three LED's light up.

Ok, a simple device to build, assuming you use a Decade Counter. But, where's the fun in that? I'm building this without the help of any sort of IC's (well, 555's maybe, if need be to expand the devices useability).

My problem lies in trying to get an LED to light up, and STAY lit. My idea was to make it so that the switch is, when released, ON. The switch would be connected to a capacitor, that would be charged when the switch is released (since it's on). Since we're dealing with DC voltage, the capacitor wouldn't output any sort of current to the opposite terminal.

Now, you depress the switch (switch is now off), and the capacitor releases its charge into a transistor, which lights the LEDs.

I'm pretty sure that would work. Problem is though, once the capacitor loses its charge, the LED goes off :/

So, does anybody have any ideas how to make said LED STAY on once the capacitor releases its charge? I was thinking of maybe putting the capacitor in parrallel with a resistor. I'm nowhere near sure if that would work, was just a basic idea I had.

Anyway, can anybody help out here? Parrot?

 

[DreadLord]

I read the thread title.

Good luck!

 

[Vegeta897]

Sorry that I can't help, but I'd just like to leave a comment.

Electronics have always interested me... It's like programming, but more physical. Am I right? I'd probably like it if I tried it.

 

[Geogaddi]

Sorry that I can't help, but I'd just like to leave a comment.

Electronics have always interested me... It's like programming, but more physical. Am I right? I'd probably like it if I tried it.

Same here. Problem is that sort of thing is difficult to get into without someone to help you along.

 

[hungryduck]

Sorry that I can't help, but I'd just like to leave a comment.

Electronics have always interested me... It's like programming, but more physical. Am I right? I'd probably like it if I tried it.

It involves a lot of boolean logic, NAND, NOR, gates etc.

 

[Dekstar]

Sinko I did an AS course in Electronics (AS is further education, like college). You can do it but I don't think you'll be able to do it with a capacitor. You'd need some D-type Flip Flops (Used for up-counters), and yeah possibly some gates. Gimme a bit and I'll draw up a plan for what you can do.

 

[Steven]

Sorry that I can't help, but I'd just like to leave a comment.

Electronics have always interested me... It's like programming, but more physical. Am I right? I'd probably like it if I tried it.

It is actually but I forgot it all, it was quite fun when I knew how.
More simpler then programming imho

 

[Solaris]

Have you tried hooking up a thermal resistor, and keeping the Sligon ion counts regulated with the temperator? You could rig it up quite easyilly so that the rise in the current, raises the counts, thus enabling the capacitator.

 

[Dekstar]

Here you go. Solaris - you seem to know about it a bit, so could you tell me if this would actually work?
http://img.photobucket.com/albums/v303/dekstar/LEDlightingcircuit.jpg

EDIT: Heh, took pic down because it's got a width of 2450 pixels.

Let me walk you through it. The switches are attached to a schmitt inverter, a resistor, and a capacitor. This is called a 'Debounced switch', and it useful if you're using an old switch which is basically just two pieces of metal (Newer switches have these inbuilt). Poorly made switches have 'bounces' when you press them, where the contacts sto ptouching for a second then re-attach. Needless to say this can mean one press of the switch can count as many, because the switch keeps attaching then re-attaching then attaching again. A debouncer stops this by the capacitor smoothing out the jitters when the switch temporarily disconnects.

The D-type flip flops are basically there to keep one LED lit even if you release the switch. Once you press the begin switch once, a pulse gets sent to the first clock. Then, whatever is at D is always passed to Q on a clock pulse, and in this case, '1' will be sent to Q (as D is high). Therefore the LED will light as there is a Potential difference between it at the 0v rail. This will also send the next D 'high' as Q(1) will stick at 1.

The EOR Truth table is:
A B Output
0 0 0
0 1 1
1 0 1
1 1 0

This means that the next D-type's clock will only get pulsed when either NOT Q (The Q with the line above it), OR the switch is 1. As NOTQ will be 0 (and stay 0) after the first clock pulse, the switch will send a pulse to the second D-type whenever it is pressed. Then whatever is at D (high) is passed to the next Q, and lights the second LED.
Rinse, and repeat.

The reset switch listed is to reset all LED's to 0 so you can restart the circuit. It doesn't need to be debounced, but I find that why not debounce it. It doesn't harm the circuit.

 

[Solaris]

I'm not that certain on what effect debouncing it might have on the invertor, but from what I can see it should work.

 

[Parrot of doom]

Just use batteries instead of caps.

 

[DEATH eVADER]

I'm constructing a simple device that, basically, shows how many times a button has been pressed.

It consists of three LEDs and a Normally On/Off switch (the kind that springs back up, so you have to hold it down to keep it on/off, depending no which contacts you're using). Each time the switch is depressed and released, an LED lights up. Press the switch twice, and two of the three LED's light up.

Ok, a simple device to build, assuming you use a Decade Counter. But, where's the fun in that? I'm building this without the help of any sort of IC's (well, 555's maybe, if need be to expand the devices useability).

My problem lies in trying to get an LED to light up, and STAY lit. My idea was to make it so that the switch is, when released, ON. The switch would be connected to a capacitor, that would be charged when the switch is released (since it's on). Since we're dealing with DC voltage, the capacitor wouldn't output any sort of current to the opposite terminal.

Now, you depress the switch (switch is now off), and the capacitor releases its charge into a transistor, which lights the LEDs.

I'm pretty sure that would work. Problem is though, once the capacitor loses its charge, the LED goes off :/

So, does anybody have any ideas how to make said LED STAY on once the capacitor releases its charge? I was thinking of maybe putting the capacitor in parrallel with a resistor. I'm nowhere near sure if that would work, was just a basic idea I had.

Anyway, can anybody help out here? Parrot?

Can't read all that, is it possible to show us a diagram of the layout?

I don't think putting a capacitor in parallel with a resistor is useful for this simple circuit

 

[JNightshade]

Wow, for all I know, Solaris is pulling this out of his ass

 

[sinkoman]

Wow, for all I know, Solaris is pulling this out of his ass

The first post i'm pretty sure he did.

There's no way I need to get involved with ions in this project :/

And that seems all fine and dandy Dekstar, but I want to stay the f*ck away from any sort of IC.

 

[Solaris]

The first post i'm pretty sure he did.

There's no way I need to get involved with ions in this project :/

And that seems all fine and dandy Dekstar, but I want to stay the f*ck away from any sort of IC.

I did....
But then dekstar wasted loads of time explaining the circiut, and I felt bad for wasting his time

 

[sHaDdoW]

If you want to latch a led on one press of a momentary switch. Look into latching relays. This can be done without IC's.
Electronics can be very hard. It has some of weirdest maths i know. Espically analog stuff.

Electronics and programming go hand in hand. Most of my electronics stuff involves proggramming microchips in asm , and sometimes C when i can't be bothered with assembly. As we all know asm can be really complicated and long winded sometimes.

 

[kirovman]

Oooh, electronics.

I used to know a fair bit about integrated circuits, capacitors and that, but sadly the knowledge is lost in the sands of time.

I'm interested in seeing the solution though.

Good luck!

 

[sinkoman]

If you want to latch a led on one press of a momentary switch. Look into latching relays. This can be done without IC's.
Electronics can be very hard. It has some of weirdest maths i know. Espically analog stuff.

Electronics and programming go hand in hand. Most of my electronics stuff involves proggramming microchips in asm , and sometimes C when i can't be bothered with assembly. As we all know asm can be really complicated and long winded sometimes.

Maybe i'll rip apart one of the relays I have, and see if I can't glue a small latch onto the base of the coil. Then, make it so that three relays all have their switches attatched to a mechanical switch on the base of the project.

Much more complicated than it needs to be though...

OK, new idea. What if I had it so that flipping the switch somehow triggers an infinite loop?

Like this http://hyperphysics.phy-astr.gsu.edu/hbase/electric/imgele/dcx7.gif only the there is a third half of a loop, so that when the first is started, the second is started, which in turn starts the third, which keeps going (due to the second) even if the first goes down.

 

[Dekstar]

Well I couldn't do it with simple gates. What about a magnetic switch that switches the LED's input to the voltage line when you press the switch? I don't know what you would do with the other LED's.


My head hurts

EDIT: It's incredibly hard without more than one switch

 

[JNightshade]

Make sure you don't overshift the flux capacitor when you trigger that infinite loop

 

[Ikerous]

Use three different level breaker switches

 

[Dekstar]

Ok my friend (and also AS Electronics taker), has done it with gates:

Not sure how to get rid of IC's altogether.

 

[dream431ca]

You could use an inductor in parallel with a capacitor. Basically the current will bounce back and forth through the LED, but it wouldn't last very long. Your best bet is to use the IC.

 

[sHaDdoW]

Latching relay one press of a switch and the light won't go off untill you reset it.
http://img235.imageshack.us/img235/6709/hh6da.jpg
You reset it by breaking the circuit here. Use a transistor or something. When the base of the transistor stops getting any current, it should cut of the circuit.
http://img235.imageshack.us/img235/4486/untitleddsdf0iy.jpg



Thats solves the capictor problem how to get the leds to turn on in sequence is your problem.
You use flip flops if your going to use logic. Infact i've got a good flip flop counter design right here if you want it. It can count higher then 3 . You can set for 10 states(Decimal) or 15States(Hex). You can then use another counter to count the 10's etc.

 

[DEATH eVADER]

Ok my friend (and also AS Electronics taker), has done it with gates:

Not sure how to get rid of IC's altogether.

Did you program a custom chip for those logic gates?

I don't want to do Truth Tables tonight.

What are trying to accomplish from this design, to see who has the fastest trigger finger?:thumbs:

 

[Dekstar]

Did you program a custom chip for those logic gates?

I don't want to do Truth Tables tonight.

What are trying to accomplish from this design, to see who has the fastest trigger finger?:thumbs:

No idea I didn't do it. I wouldn't have thought so anyway.