LED flashing/beating heart help/advice

[carebare47]

Hello,

I was thinking of making a LED heart (maybe three concentric heart shaped rings of LEDs) that flashes/pulses/dims (or other patterns) for my girlfriend. I was wondering what pattern to use and how I would go about creating something that will do that. I know a little about astable flip-flop circuits and have tried to use a 555 timer before (didn't succeed last time, but I have improved much since then). I was going to build the final design on strip board. I could make one that just alternates two series' of LEDs but I was hoping for something a little more complex. Any and all ideas are welcome =)

Many thanks,

Tom

 

[LTX71CM]

One of these might be what you're looking for
http://www.instructables.com/id/"Beating"-LED-Heart-T-Shirt-finished!/
http://circuitdiagram.net/flashing-heart-circuit.html
http://theadlab.blogspot.com/2009/10/alternate-led-pulsing-via-555-timer.html

 

[RAMSELECTRONICS]

It's nice!

 

[carebare47]

Help with the 'circuitdiagram.net/flashing-heart-circuit' circuit!!

Hello again,

Firstly, thanks for the links. I decided on the http://circuitdiagram.net/flashing-heart-circuit.html one. I have constructed the circuit on a protoboard (but have used BFY51 transistors as it is rather difficult to find and 2N3643s near me. Will the BFY51 still work? It seemed similar enough). So far I have only put a few LEDs in (to see if the circuit works before I construct it on strip board). There is one LED coming from Q1 (which flashes just fine), and two each from Q2 & Q3 (Q2 LEDs flash, Q3 do not). I am not really sure what the dotted lines on the schematic mean. If I connect these dotted lines then LEDs from Q2 & Q3 flash at the same time. If I don't, then only LEDs from Q2 flash. The Q2 LEDs are flashing at a frequency of about 1Hz (didn't have a potentiometer for R9 so I used a fixed resistor and improvised with 4x 4.7uF capacitors in parallel for the capacitors between pin 1&3). Also, the LEDs from Q2 don't flash on and off, they flash from bright to dim(ish). Any ideas? Could someone please explain these dotted lines? ^_^

Many thanks,

Tom

 

[barathbushan]

if you have a multimeter check the base of q2 and q3

 

[carebare47]

if you have a multimeter check the base of q2 and q3

The bases of both were fine, but the actual Q3 transistor was not. Tested it with my multimeter and it wouldn't give a hFE reading. Still don't really understand the dotted lines though. Swapped it with a working one and all is good. Now to order masses of LEDs and start transferring it to strip board =)

Many thanks,

Tom