Alot of questions for an easy piezo project!

[Junior957]

Hello everyone,

First off I'd like to thank you for visiting the my thread. Each time I've come to this forum I've left with assistance and more knowledge and because of this forum in the last year I developed a working device for myself. But I'm sure you all know that when you personally build something it usually can never be considered perfect!

With that said I know my device is not perfect and I know how to fix it. I just physically don't know how to build that fix!!  Hopefully you all can help.  :)


My device now is a simple piezo hooked up to a lever switch. When the switch gets hit of course the piezo beeps. I have it hooked up to a 9V via a simple 9V connector and the lever switch I used little connector spades clamped to the wires. (I can take a picture if needed - but probably not.)

Anyways, the lever is usually at rest (90% of the time) but when it is struck it's multiple times and fairly quickly usually. Occassionally the piezo will skip or the tone will blend. I know a timer will help but I'm not good with this sort of stuff.

First of all, I know I need a board for this to go on. All the ones I see at RS and the like - even the smallest ones are too big to fit in the housing I need it to.  Can you cut those boards to size, carefully of course?  Next, I'd like to add a button cell to the device rather than a 9V (if possible), I'm not sure how I'd achieve this.  Going in line with how the device would operate, I'd like to add an on/off switch as my current build doesn't have one. I noticed however a lot of those were like the lever switch - they had "prongs" on the bottom... I'm not sure how you would attach those to the board.

Then I'm not sure where you would put the timer. I imagine between the lever switch and piezo.

As you can see I've got this worked out fairly well (I think!) but I'm just not very good at electronics. I've read a lot of resources but having no hands on experience is tough. 

If anyone could lend any general assistance with how I could accomplish this I'd appreciate it very much!!!

[Junior957]

Ouch, no replies!  :(  That's quite alright though as I know how helpful this forum can be provided I give enough details and I learn some of this myself. 

So I spent a couple hours looking up information while I was at my in-laws yesterday.  I realize now that I can cut veroboard to suit my fancy - which is great! :)  However I'm still in the dark here a bit as I have really no electronics 'know-how' or experience for that matter.

I'm going to try to draw up a little schemeatic of what I need to do but I know it will be a very rough diagram.  I know it sounds really stupid but I don't understand how to make a full circuit (power, ground) using the veroboard as I'm using to simply hooking up red and black wires.

So for a parts list I know I need:
1)Veroboard
2)A 555 timer
3)A Piezo
4)On/off Toggle Switch
4)A Battery Connector (I have a bunch of left over 9V connectors so I figured maybe use those until I get the hang of this stuff.. then I could order button cell holders.)

One thing I do not understand though is the whole monostable, astable, bistable thing in relation to the timer.

If I would like to take the input (from the lever switch being pushed) and make sure that each time that switch is depressed that the piezo gives the same "beep" whether I push the switch 10 times fast or just once every 10 seconds.... what mode would be the best?

From looking at the charts it seems pin 1 and 8 are the 'ground' and 'power' - but from there I'm lost on how I would connect everything.

As I mentioned I can show a video of my device in action if it helps.  I figure though this is a fairly simple design/device for the experienced but for someone like me it seems very difficult.

Once again I appreciate any help that can be offered  to this electronics wannabe!!! :)

Ed

[Hero999]

You need a monostable circuit.

The modes are as follows:

Astable, a circuit which always has an unstable (i.e. changing) output; an oscillator such as an LED flasher.

Bistable, a circuit with two stable output conditions: push one switch to turn on and another to turn off. A typical application is a burglar alarm which needs to be triggered once the light beam is broken and remain triggered until the reset switch is pressed.

Monostable, a circuit which only one stable output state such as a timer: the circuit is stable until triggered, once triggered it will go it will change state for a certain length of time.

Here are a couple of sites which contain information you'll probably find useful:
http://www.kpsec.freeuk.com/study.htm
http://www.abcofelectronics.com/555timer.htm

[Junior957]

Evening Hero,

Thank you very much for your assistance.

It seems one of the links you provided I've already been heavily reading from! (The 'KPSec' website) The other, ABCof Electronics was very useful as well.

It seems to regulate time on one of these devices you need to use specific capacitors and resistors.  Unfortunately I was not able to find any combination which would be useful for my application which would require at least one "beep" every second or, even better, the capability of 2 a second.  (Unless the timer itself is capable of it as a preset?)

I'm going to put together (well I already have started) a veroboard drawing of what hopefully I will need to do.

Do you think I will need any other resistors or capacitors in my design if I am going to just going to first test it and let the timer do it's thing setting the 'wave length'?

It seems that no matter what I do I can't figure out how to diagram this out.  I'm just a real dud at this.

I am going to post a request in the 'Job Offer/Requests' section and hopefully someone (for a small fee) would be willing to come up with a schemeatic and possibly put together a device for me so I can copy from so I can learn this.  I'm a very hands on person so I feel this would be the best way.  I would like to make a bunch of these as I'm using them for fishing and times 5 poles (plus another 5 for my father) would mean I need to make 10. 

[Junior957]

I've built my (fishing) device using basic wiring, however to achieve a more perfect device I know I need to make a board with a timer.

It functions as an alarm and when the lever is pressed the piezo gives a nice steady beep (except when the lever is hit too quickly).

I'd like it to run off of a button cell if possible, but a 9V is okay. Currently mine works on a 9V because snap connectors are so easy to use.  I'd also like an off/on switch (anything simple will do).  I use a small SPDT lever switch for my alarm currently and it works well. I would like that to be the trigger for the timer and of course the piezo be the output. I was thinking of the "timer" portion of it to be about a half or .75 of a second. I'm trying to pack all of this into a little housing so if it could be made really small that would be great.

[Junior957]

Hello Everyone,

I've tried to figure this out but can't seem to.

See post linked below for more information:
http://www.electronics-lab.com/forum/index.php?topic=21584.msg95489#msg95489

If you are interested in this please let me know. I'm willing to pay a small fee via paypal if you can build this for me and essentially show me how to do it.

Thank you very much.

Ed

[Hero999]

We have a no duplicate thread policy here so I've cut out the part describing what you want, moved it to this thread and replaced it with a link in your other post.

The formula for calculating the resistor and capacitor values can be found on the datasheet and there are also plenty of online calculators.

If you're having problems building this, I suggest you try to build something more simple first such as lighting an LED with a series resistor.

By the way, this won't work from a single button cell, the 555 has a minimum working voltage of 4.5V, you need to use two button cells in series for 3V, aTS555 which works down to 2V and a piezo with as lower voltage rating.
http://www.westfloridacomponents.com/mm5/graphics/ds/555,pdf.pdf

I would probably suggest using a different IC altogether and using a piezo transducer which needs an external oscillator but the circuit is more complicated so it wouldn't be helpful.

What exactly are you struggling with? Is it looking at the schematic and figuring out what connections go where?

Here's the circuit you need to be building:


The trigger is your pushbutton switch.

You don't need the 10k resistor between pin 4 and +Vs or the reset button. Just connect pin 4 directly to +Vs.

The connections going to 0V simply go to the negative battery terminal and those marked +Vs go to the positive.

The piezo is simply connected between pin 3 (output) and 0V (negative).

C1 is polarised which means it needs to be connected in the right way round, otherwise it might explode. The negative terminal is marked with a black stripe or will have an arrow pointing towards it.

The pinout for the 555 is shown below:


The 0.01