Timer device

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Andyjones

New Member

• Oct 15, 2006

• #1

Hey guys

I want to make one of these:

http://www.thinkgeek.com/gadgets/electronic/79be/

any ideas on how it can be done, i guess i can get all the bits from RS but what would I need, could it be done with a 555 timer or a simple pic chip and a speaker?

***********EDIT************
I have found this

**broken link removed**

This would surly do exactly the same as the circuit available? simply by changing R1 and R2 and the capacitor?


Thanks

AndyJones

 

Last edited: Oct 15, 2006

Hero999

Banned

• Oct 15, 2006

• #2

Yes, use the calculations given on the page. Connect a piezo buzzer from pin 3 to +V, use a very high duty cycle (98%) and set the frequency for 0 .005Hz.

 

picasm

Member

• Oct 15, 2006

• #3

It could be done with minimum components using a PIC with internal oscillator to generate a pseudo-random number generator to vary the delay between a few minutes and about 5 minutes, Then generate a very short chirp.

It would probably drive someone mad enough to destroy it when they find it though.

 

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HarveyH42

Banned

• Oct 15, 2006

• #4

Here is a circuit I built to scare off the neighbor's cats (many, too many...).

If you go through and change the timing components it should work the way you want. Might even be good as is, because you can hear this, even though it was intended to be ultrasonic (depends on temperature). You can use a 556 instead of 2 x 555s, and should be fine on a 9 volt battery, mine is plugged into the wall, and had a 12volt walwart.

 

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HarveyH42

Banned

• Oct 15, 2006

• #5

Sorry, forgot the attachment...

Yeah, $25 does seem a little much...

 

Attachments

• Catscarer.jpg

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philba

New Member

• Oct 15, 2006

• #6

If you want to get devious, use an LDR (light dependent resistor) that prevents it from working when there is light. They will have to find it in the dark... There are a number of inexpensive kits that do this.

 

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Andyjones

New Member

• Oct 15, 2006

• #7

I like some of your ideas
I have not got a pic pregrammer,although that would be the best way forward.

So I guess using 555's is the best way forward.

Huge thanks to every one, especially HarveyH42.

One final question, is it best to use Maplins or RS website?

Thanks

AndyJones

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Oct 15, 2006

• #8

Andyjones said:

I like some of your ideas
I have not got a pic pregrammer,although that would be the best way forward.

So I guess using 555's is the best way forward.

Huge thanks to every one, especially HarveyH42.

One final question, is it best to use Maplins or RS website?

Click to expand...

Two things you need to do!.

1) Enter your location in your profile (so people know where you are), which is presumably the UK?.

2) Stop saying 'RS' - use 'RS Components', otherwise you confuse people, the Americans tend to shorten 'Radio Shack' to 'RS'.

 

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HarveyH42

Banned

• Oct 15, 2006

• #9

Actually, RS is short for Radio Shaft (overpriced crap). Any place is a better choice, although some people have little choice sometimes.

 

Hero999

Banned

• Oct 15, 2006

• #10

Just get the cheapest.

RS Components are better than Maplin, in general, the latter are only any good because you can go there and buy stuff over the counter.

Maplin used to be an excellent hobbyist electronics store ten or so years ago but have had their day in my oppinion. They used to sell a wide range of componants and some great kits but nowadays they only sell a quater of the componants they used to and their kits have turned to heavily dumbed-down tackey pieces of crap. The main reason for their decline, is it's so cheap to buy electronic equiptment and SMT componants aren't too popular with hobbyists in general.

 

picasm

Member

• Oct 15, 2006

• #11

Maplin can be convenient if you just want a few parts quickly - but best to do a store stock check on their website or you may make a wasted journey.

For things like 555 timers, ebay is worth a look - plenty of sellers for those parts.
Here is a list of a few more UK web component suppliers from my bookmarks. (I have not ordered from many of them and am not offering any recommendations!)

Farnell - http://uk.farnell.com/
Rapid Online - http://www.rapidonline.com/
Bowood Electronics -
Conrad Electronics - http://www1.uk.conrad.com
CPC - http://cpc.farnell.com (Part of Farnell group)
Cricklewood Electronics - http://www.cricklewoodelectronics.com
Dannell Electronics - **broken link removed**
East London Components - http://www.elclondon.co.uk/
Electron Electronics - http://www.electronelec.co.uk/
ESR - http://www.esr.co.uk/
Greenweld - http://www.greenweld.co.uk/
Harrison Electronics - **broken link removed**
Grandata - http://www.grandata.co.uk/
J A Crew - **broken link removed** (also sells hardware etc)
PW Electronics - **broken link removed**
BitsBox - **broken link removed**

 

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Andyjones

New Member

• Oct 16, 2006

• #12

Thanks again everyone., my profile has been updated and I shall use "RS componants" in future, were I normally come from we only use RS.

I have found this:
**broken link removed**

This the perfect thing to start me programming pics isn't it?

Just need to start learning how to code it now. lst time I did pic chip stuff was back at college!

Regards

Andy Jones

 

picasm

Member

• Oct 16, 2006

• #13

There was a discussion on this forum about the K8048 a week or two ago - Whilst it appears to be a good thing to start with, it does have limitations.

 

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Andyjones

New Member

• Oct 16, 2006

• #14

ok then. I'll have a look around. I have just discovered the FAQ on pics which was very helpfull.

I have just downloaded Prolog which was the program I used at college. SO I shall have a crack at using that.

Thanks everyone!