Is there something to use to flash 2 led lights quickly?

[Barbon]

I want to create a device which will flash 2 led red lights for 2 seconds then off for 2 seconds then on for 2 seconds then off. I want this to come on after a certain time using a plug timer but with one of these plug timer things you cannot obviously program it to turn something on and off quickly- in this case the led lights.

Is there anything anyone can recommend I can get which could do this? bear in mind I want the lights to start flickering after 2 hours then flicker continiously for seconds at a time like: 2 flashes then off for 2 or so seconds then 2 flashes again and so on.

Thx.

I should note I am in England so use UK plug related stuff and voltage.

 

[BobK]

I could do this trivially with a PIC microcontroller, but it is a long learning curve if you are not already competent with them.

Bob

 

[davelectronic]

Led flashing rate

Hi there there are a few simple circuits out there that only use one or two small transistors, ive not got one to hand, but from what i recall the flash rate and frequency can be made faster or slower by altering the capacitance and resistance values in the circuit, Google it there is probably a circuit out there. Dave.

 

[BobK]

Hi there there are a few simple circuits out there that only use one or two small transistors, ive not got one to hand, but from what i recall the flash rate and frequency can be made faster or slower by altering the capacitance and resistance values in the circuit, Google it there is probably a circuit out there. Dave.

But they will not come close to what the OP wants:

1. delay 2 hours
2. blink for 2 seconds
3. off for 2 seconds
4. blink for 2 seconds

Doing this with discrete transistors would be quite complex.

You couuld possibly do it some one-shots and 555 timers, but the timing would not be very accurate. This is why I think a microcontroller is actually the least complex solution.
A $.50 microcontroller, 2 LEDs and 2 resistors wouild be the entire circuit (and a crystal if the timing was critical)


Bob

 

[duke37]

You will need to provide a low voltage power supply and could build an oscillator from two transistors (multivibrator) as Dave says or use a 555 integrated circuit as an oscillator. The 555 could drive the led directly with a suitable series resistance.
How much do you know and what are you prepared to do?
You can get a led with built in oscillator, this would be the simplest way but may not comply with your 2sec specification. They look to be very tolerant of power supply voltage and no extra components are required. Try Maplin.

 

[Barbon]

You will need to provide a low voltage power supply and could build an oscillator from two transistors (multivibrator) as Dave says or use a 555 integrated circuit as an oscillator. The 555 could drive the led directly with a suitable series resistance.
How much do you know and what are you prepared to do?
You can get a led with built in oscillator, this would be the simplest way but may not comply with your 2sec specification. They look to be very tolerant of power supply voltage and no extra components are required. Try Maplin.

Any idea where I can get an LED with a build in oscillator? I don't think they have 1 in maplins. Anyone know where I could get one? (I am in uk pls remember) would this work with a standard uk plug timer? thx a lot.

 

[duke37]

You will need a plug in timer and a plug in low voltage power supply.
Maplins have flashing leds in UK. Try searching 'flashing' on their website. Examples are UK30H, UK37S, UK38R, UK42V. These are red leds, they do other colours also.

They are obviously not rare beasts and may be found elsewhere.

 

[Barbon]

You will need a plug in timer and a plug in low voltage power supply.
Maplins have flashing leds in UK. Try searching 'flashing' on their website. Examples are UK30H, UK37S, UK38R, UK42V. These are red leds, they do other colours also.

They are obviously not rare beasts and may be found elsewhere.

What voltage leds should I get pls. (I in uk remember)

 

[duke37]

I am also in the UK.

If you look on the Maplin website, it will give details of the range of voltages which can be used. I am not looking again but I think they run on 5 to 12V or so,

Did you try the Maplin website?

 

[rootboy]

Since the plug timer is going to energize the circuit at the end of the two hour delay period, then a 555 timer makes perfect sense.

Here's a great place to start:

http://www.555-timer-circuits.com/

Specifically:

http://www.555-timer-circuits.com/flashing-led.html

Use a 220V wallwart to power the 555, one that has a 9V DC output would do just fine.

 

[Barbon]

I appreciate your answers but I still really confused i'm sorry but I think I should go through this step by step by firstly asking simple questions....

I gotta start again I think.

Can anyone tell me where to get a simple plug timer which you can have turn on for 30 seconds or a minute after setting the times for it to come on after hours? I trying to get this part accomplished first.

Sorry about the confusion here lol.

 

[rootboy]

I appreciate your answers but I still really confused i'm sorry but I think I should go through this step by step by firstly asking simple questions....

I gotta start again I think.

Can anyone tell me where to get a simple plug timer which you can have turn on for 30 seconds or a minute after setting the times for it to come on after hours? I trying to get this part accomplished first.

Sorry about the confusion here lol.

No problem.

What is this device for? Is it to remind you to turn something off after being on for an hour?

If all that you want to do is to flash a couple of LEDs after a delay of an hour, and you want to use a plug in timer to accomplish that, then let the timer module handle the first hour. That is, if you turn the output of the module on after the hour off period.

Something like this could be used (you would have to find the 220V analog to it for the UK):

http://www.grainger.com/Grainger/TORK-Timer-6WPA0?Pid=search

But the question is, at the end of the hour, do you want the outlet to come on, or go off? If it turns on, then my previous answer is still valid, if it turns off after the hour, then we would have to change things.

Could you sketch up a timing chart for us please?

Thanks

 

[jackorocko]

How many times do you want the LED to flash during the 2 second on period? If you just want it to come on for 2 seconds then off for 2 seconds then rootboy suggestion is top of my list.

 

[TheLaw]

555 I think would work...as it should be able to drive the LEDs without the need for addional components.

 

[mechtronics]

a 555 timer is probablt the best way to go with it.

 

[BobK]

a 555 timer is probablt the best way to go with it.

No, a microcontroller is the best way to go. It can do exacly what the OP asked for, including the hour dealy and blinking the LED only twice, with only a resistor and LED as external components. It would take 3 555 timers and 10 or 15 other components to do the same.

Bob

 

[Barbon]

ok I just need to know now forgetting everything else about the led lights etc but I need to know where to get a timer that comes on and only comes on for a minute or so. Nothing else pls.

 

[Barbon]

anyone? pls help.

 

[(*steve*)]

People have probably given up trying to help you because each time they suggest something you change the requirements.

That, and your unwillingness to answer questions, has probably caused most people to lose interest in helping you.

Perhaps you could start by reviewing the entire thread and answering all the questions.

 

[mechtronics]

u could do this with a couple of 555 timers and an inverter i reckon