Electronic Timer

[stanfield]

Anyone know a web site where I can find a schema of a countdown timer with 4 digits (minutes & seconds) and, at the end of the time, BOOOOM ! (a discharge passes through the detonator...) ? I'm looking for something simple, easy to make and cheap...

thanx !

[Tony Montana]

NE555 timers are worth looking into:
http://www.ee.ed.ac.uk/~kap/Hard/555/aplications.html
http://www.proaxis.com/~iguanalabs/555kit.htm
A more simple setup can be used, using a transistor as an electrical switch. An alarm clock is opened and the two wires attached to the speaker are removed and attached in series to a transistor, detonator and power supply. When the alarm is triggered, a small electrical signal is sent to the transistor. The transistor works as an electrical switch, and connects the circuit to the power supply actuating the detonator.

[Victim]

<a href="http://innercircle.topcities.com/Timer.gif">Clock Timer Diagram</a> heres a little simple design, Im sure you call all work it out, if ya need me to explain it let me know.
EDIT: you will have to cut and paste as Topcities doesnt allow linking, so you will have to cut and paste, sorry to go off topic, but does anyone know a good site that does allow linking of img's?

[This message has been edited by Victim (edited July 31, 2001).]

[nbk2000]

www.freeyellow.com (http://www.freeyellow.com) allows linking to pictures. It's what I use for all my pictues.

------------------
"The knowledge that they fear is a weapon to be used against them"

Go here (http://members.nbci.com/angelo_444/dload.html) to download the NBK2000 website PDF.

Go here (http://briefcase.yahoo.com/nbk2k) to download the NBK2000 videos.

[Jumala]

When you can wait some days I can mail you a plan of a timer. The plan and the solder plan is ready but the pics of the device and the user manual with calculation formulas for the time aren´t.
It will cost 2,5 US$ (all parts including battery and 12V 20mA lamp)
Standart time is 2 minutes but all other times are possible.


A 555 timer don´t work for this matter.
It gives a immediate output signal and fall back after the time.
You need a timer with a defined delaytime and a output impulse after this time.


Oh, I forgot the 4 Digit display.
This is in my opinion bullshit. Who will stay near the timer to look on this display while countdown?
It is only good effect for movies.



[This message has been edited by Jumala (edited August 01, 2001).]

[stanfield]

all right ! send me the schema or the file (I'm working with eagle 4.03 + crack http://theforum.virtualave.net/ubb/smilies/smile.gif)

see ya...

[stanfield]

I found these two timers but I think they'll cost maximum $$$ to make them...

http://www.piclist.com/techref/microchip/cntdn/index.htm

and

http://www.piclist.com/techref/piclist/cheapic/worktime.htm

Tony Montana, Victim : I know the 555, which here don't know the 555 ?! but I really hate this circuit because of its imprecision...

let's see if the Jumala's timer will be good... http://theforum.virtualave.net/ubb/smilies/smile.gif

see ya !

[Victim]

NKB, www.freeyellow.com (http://www.freeyellow.com) isn't free, although there is a "free sign up" I have to include my credit card details..?

[stanfield]

Hey, Jumala, I found your timer on my second hard drive... is it right ?

http://www.geocities.com/st4nfield/

(maybe copy and paste...fucking geoshities)

see ya !

[Jumala]

Yes, right it is the timer in the larger version.
The new timer is similar but I reduced parts and costs so much as possible.
It isn´t crystal controlled but a ones presetted time is very exact.

The pics of the device are ready now and I will send the plan.

[nbk2000]

Victim, when I signed up with freeyellow in '98 it was free, and I have never given them a CC# (because I don't use the Mark of the Beast http://theforum.virtualave.net/ubb/smilies/wink.gif) so I don't know if they've started charging, or maybe you're confusing their ad free services which DO cost. The free version is what I've been using and you don't see the ads when posting picture links.

Maybe you need to read their site more carefully.

------------------
"The knowledge that they fear is a weapon to be used against them"

Go here (http://members.nbci.com/angelo_444/dload.html) to download the NBK2000 website PDF.

Go here (http://briefcase.yahoo.com/nbk2k) to download the NBK2000 videos.

[stanfield]

Hey, Jumala, I found your timer on a web site (yours site ?) but I can't remember which one... is it down ? if no, could you give me the URL plz ?

[stumps4arms]

how bout light sensitive timers.. like when a certain part of the circuit is exposed to light it makes the circuit active

[Victim]

stumps4arms, the sensor from the top of street lights would do a good job of that, as as soon as it gets dark it sets the switch and the lights come on, when it get's light again, they go off, you could I should think, be able to change this around on the electronic's inside, just take it out an turn it around? I don't know if you would be able to do that but it's an idea. I don't know if the US street lamps run on the same idea, or just a big switching board on a timer..?