Help making a timed flash circuit

[chownsy]

Not sure if i hav a bread board, Think I just have circuit board you have to solder the tags to it (stripboard)

 

[magnatro]

hey, test first.. then solder it on... if you need to be prominent in Electronics you must have one..

 

[chownsy]

Rightio, Ill go see if dad has one, if not ill buy one

 

[chownsy]

Solderless Prototyping Breadboard.
80mm x 60mm

Will this be big enough for what i need to do link **broken link removed** (about half way down page)

 

[chownsy]

I have my parts

How does this prototype board work and how do i work out which pin is which on a 555 timer?

 

[magnatro]

Stripboard
this may help...

 

[chownsy]

I have made this circuit and there a few issues

1. Monostable section works and gives me 13 seconds (will come down to the 5 seconds when i have a working full setup) but the Astable section dont seem to work, it gave me a flash using 1 LED but then aint done it since.

2. The 7 LED's dont flash at all (they dont even light, SO not sure where you got that 30v spike from on your test data)

3. The buzzer and LED's have to come on at the same time. The buzzer is so that if you dont see the LED's flash you know that the time is up.

4. The 30000 MCD LEDs are not bright enough (was in a 1m x 1.5m room and it hardly lit the room) - this was wired in parallel to a 3v source (2x AA batteries)

Can someone advise me how to progress please.

 

[cowana]

Can you post a photo of your setup? I/someone might be able to see what you're doing wrong.

 

[chownsy]

Ill get the photographs laters.

In the mean time i have being doing some research into this diagram.

1. The Monostable and Astable are wired up correct = All good there
2. The recommended working voltage for the 555 timer is 5v-15v = I am powering this with 3v
3. The LED's have a need for 3.6vf and 50mA each
4. The 7 LED's are not bright enought and will need either more in series or ?? x 7 in paralle and series,
5. The LED's need a capacitor to discharge to give the LEDs the flash. As atm they dont flash at all and the way i have it wired with the NPN transistor, the LED (if only 1 connected) stays permently on)
6. The Astable setup does not seem to reset so after the monostable gives you the xx time and in theory gives a flash (got it working with just one LED) 2nd time around this does not work.

 

[magnatro]

hi chownsy, sorry to hear that it didn't worked like it should be,but in theory and in simulation, it worked perfectly,... i shall paste another diagram.. this will have enough time to illuminate the room.. so it would not be like a camera flash, because the delay will be more here, if you want a flash, just couple a capacitor at the pin # 3 of 555 which connects to the base of the transistor.. and if you need just a beep, add another condenser.

 

[chownsy]

Before i do the other version you have there, can you take a look at these photos and see if you can see a mistake.
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[colin55]

Here's a simple circuit that makes a flash camera keep flashing:
**broken link removed**

 

[magnatro]

Here's a simple circuit that makes a flash camera keep flashing:
**broken link removed**

yeah, he saw that and he need only an led based flasher that he can control the timing of the flash..

 

[magnatro]

chowsy , check whether the LEDs are connected in the right way.. and if it doesn't work increase the voltage a bit.. experiment with the circuit..that way you can learn it more.. try the improved one if it fails. my mail ID is magnatronelectronics@gmail.com , so we can chat about what the problem is. try the new circuit, you can increase/decrease the number of LEDs, as you like. you can make it with the help of components that you already have..

 

[magnatro]

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[magnatro]

An improved design

This is an improved design of the flash circuit... this will suit your needs WITHOUT any problem.

 

[cowana]

Magnatro - I think there is feasibility in the dual 555 version. I wasn't impressed by your previous deisgn which chowsey can't get to work. However, I think post 50's design is OK and should work when powered from 9v, although I'd be wary about the lifetime effects of pushing 55mA through the LEDs with them all wired in parallel.

I hope chowsey can get a working project with the parts he has bought - I don't think it is fair to get him buying a 4017 to completly redesign the project.

Andrew

 

[chownsy]

How long do you think the LED's would last on that circuit then? I dont want them to all blow after 5 uses for example.

I will have a go at making the circuit in post 50 and come back to you with a result shortly.

Regards

Richard

PS name is Chownsy not chowsy or chowsey hehe (least its not the worst we have had our name called, Ive had all sorts of weird names instead of chowns)

 

[magnatro]

Sorry my mistake...Chownsy.. and worried about you completing the project on time..
Magnatro

 

[chownsy]

I have no specific time to complete this project. I just have a deadline of as soon as possible.