Looking for Knowledge/Assistance

[Junior957]

Good afternoon everyone,

I found this website and forum and I beleive I may have discovered the place where I will learn everything I need.

I'm trying to design something really crude for myself and part of what I need involves electronics that are not commonly available off of an old item that I could just take apart. (If it was, it probably wouldn't be nice and small and put together like I would want it to be.)

You guys are going to laugh but I need the electronic item to perform two (what I would imagine are) very simple operations. One, to sense two pieces of metal touching eachother and second, it needs to produce a noise (preferably a beep) when that happens.

I would imagine the items I would need would be. The first piece of metal, as well as the second piece which is to be struck.  A wire, or something to connect that second piece to the circuit board - and of course all the components that it takes to produce the working board, and a small speaker? (And a power source.)

I'm the type of person who likes to learn. Even if I never use this information again. How hard of an item would this be to produce?  Would this be the appriopriate place to learn?

Thank you very much,
Ed

 

[Hero999]

There is no real circuit diagram.

The two pieces of metal can form a switch, when the pieces of metal come into contact with each other, the circuit is made and the beeper goes beep. You can buy piezo buzzers which make a beep noise rather than a buzz when powered up.

 

[Junior957]

Thank you Hero, I appreciate your reply.  Whatever other information you may be able to provide or resources you may be able to point me to would be extremely helpful.  I am 100% new to this so anything is helpful.

Once again I appreciate the info.

Ed

 

[Alex Tsekenis]

Here is how to connect the components. The wires dont need to be black and red, just make sure the positive (usually red) connection of the buzzer ends up to the positive connection of the 9V battery.

The metal contacts can be aluminum foil, steel plates, copper pipes, anything. You will not be able to solder the wires on aluminum with standard solder.

View attachment 40926

 

[Junior957]

Thank you very much for that diagram Alex, I appreciate it a lot.

So its really that simple? Wow. I am a fairly intelligent person and I did not think it would be too hard to construct after learning a bit about circuitry - building the boards, etc, but I did not think it would be so straight forward. Like I said, I knew this a crude idea though.

Now once I get this mounted on what I'd like - I will have to learn brief board making to add an LED and maybe some way to amplify the tone provided the beep in this beeper isn't suitable for what I need it for? (I'd like to be able to hear it from a distance as I'm trying to run fishing line from my deer feeder - have it pull a spring - which pulls the first piece of metal to touch the contact and alert me that they are feeding so I can monitor them. I'm not a hunter, don't worry, haha.)

Once again I think you a lot.

Ed

 

[Junior957]

Alex,

One more thing. I hate to be an absolute pain but is there any way you could reccomend parts - or even a website or company for me to browse from.  I searched for piezo buzzers as Hero had suggested that appears to be what I need and also from your diagram it appears to be it as well.  Some of the websites however have many product listings and all the specifications are damn confusing.

I need mine to be as small as possible. I told you the purpose for it, so its not like it will be used all the time, but you can imagine when deer are eating the thing is probably going to beep like crazy. (I actually might need an on off switch too, thats not hard though I can do that.)

Also, I would imagine I would need those circular things that you connect to the top of 9V batterys to make the connection more solid. Could you possibly fill me in to the name of those?

I appreciate you guys help a lot.

Ed

 

[Hero999]

It depends on where you live.

In the UK Maplin is a high street shop which sell some pretty loud piezo buzzers, in the US there's RadioShack which, although similar are a different company.

Many online companies are much better: in the UK, Farnel, RS, Components and Rapid Electronics are pretty popular, in the US there's Digikey.

The loudness of a buzzer is measure in dBA at a specific distance, (normally 30cm or 1m), the higher the value the louder, it's a logarithmic scale so every 10dB is double the volume.

 

[Junior957]

Thank you Hero. I went to Radio Shack today and got exactly what I need. I found the 9V snap connectors as well.

I appreciate you guys help very much!

 

[Junior957]

Back once again for help gentlemen.


With these Piezo buzzers. If you are making something like I am where you want to make an indicator alarm - and not an electronic alarm... your sort of subject to random movements and what not and therefore I don't always get full pulses through my buzzer.

Sometimes it only gets a short zap of power from the battery while others it will make a nice connection and beep well, others the beeps will be incoherent, low in tone and mesh into one another. 

Is there a capacitor or anything I can do besides making the contact points as flush as possible to make the buzzer beep the same strength every time - regardless of the quality of the input comming in? (Sorry guys I know this is a terrible description of what I am trying to accomplish but keep in mind I do not have any electronics experience so I am very limited in how I can describe things.)

Thanks again,
Ed

 

[Hero999]

That's slightly more complicated, although not much more complicated.

You need to use a timer, to make sure the minimum pulse length is at least a second or so.

Here's a solution but it will require some learning before you'll be able to build it and even more if you want to understand it well enough to design you own 555 timer circuits.

Here are a few sites which with lots more information:
http://www.hobbyprojects.com/general_theory/circuit_symbols.html
http://www.bbc.co.uk/schools/gcsebitesize/design/electronics/materialscomponentsrev_print.shtml
http://www.kpsec.freeuk.com/index.htm

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[Junior957]

Thank you very much for the information hero, I appreciate it a lot.

I will read up on all that and report back asap.

Were you indicating I need to use the timer to allow a charge of 1 second or so or I need at least 1 second of contact to make this all work? A full second may be a problem here with my current design - but simplicity is also a key function of success so maybe if I need a full second I'd be better off trying to redesign the item before trying to make the timer. (Although I fully intend to read up about it because it interests me and could be useful in improving the design.)

Thanks again,
Ed

 

[gogo2520]

Hello Junior957
  Using a 555 timer is a good idea it can be triggered with a short pulse ( just few mil seconds)and then be configured to
send a much longer pulse to drive your buzzer

  555 timers are fun to work with, its one of the most commonly used ic's in electronics.
                                                                gogo

 

[Junior957]

Thanks gogo, that cleared up my question perfectly.  Assuming I cannot reconfigure my design I will have to go with the timer.  

It definently sounds like a fun device to work with! Heck its exactly what I was asking for (taking a short 'pulse' and converting it to a longer one for purpose of the auidble tone).  Obviously I'm sure it has a ton of other more useful application but for my asking it is perfect and spot on.

Thanks once again guys, you all have been more than helpful.  I've already learn a ton already. I found a little 9V battery holder with a cheap switch so I don't have to wire one in and can turn it off when I don't feel like hearing it.  Even that is neat to someone who doesn't typically play with electronic gadets like this. I'm typically someone who works with their head, not with their hands so I'm having fun with this project. (Although I realize it is both - you guys have basically put all the info in front of me so its easy to absorb.)

Ed