"Beating" LED Heart T-Shirt

Step 4 Make the Flip-Flop-O-Matic

Yeah, pretty much just follow the schematic again, This one's a bit more complicated.

All arrows that have letters on them DO NOT go to ground, just follow that and you're set.


I did this on a breadboard first to make sure it worked, then transferred it to perf, you could do the same if you want.

Warning: Scientific Content

The two flip-flop chips are wired to create a 4 bit shift register, this shifts a high (1) through 4 initially low (0) state bits. The high bit is shifted every peak from the timer chip. when it gets to the 4th bit the chips reset and start back at the first chip. The 2 inut nor is used to determine at what time each row of leds will light. When there is a high (1) at either input the leds will not light, but when there are no highs the leds will light. It's a simple circuit, but as this was my first time using digital logic, I am SUPER excited.

Comments

[kscientist]

is it possible to use a shift register(IC 7495) instead of flip flops??? if possible type of operation has to be used?

[avin]

Hi this is nice :P i am planning to make it on a PCB and i am wondering if i can replace those 2 LED that you use to drop the voltage to 5V with resistor? if so what value should i use? is it 100ohm? PS: the wireing on PCB is hell :P i will probably end up with burning every single LED :P

[T3h_Muffinator]

Well, I'd seriously consider just using a diode with a 2 V drop. You don't really want any resistance there, although it might work. You don't have to use an LED to drop it, you could just use a glass diode or something. PLEASE post pics when you're done, and include the pattern for your PCB! I think it's awesome that you're actually doing this. ROCK ON! -Josh

[avin]

what do you mean by glass diode? is it zener diode? i am also alittle bit confused over the 560ohm resistor in serie with all those leds. My calculation says that you are giving each LED 0.34mA on the outer ring with 42 LEDs, am i missing something here? 0.34mA sounds abit low....?

[T3h_Muffinator]

A glass diode could be a zener, just any diode with a 2v forward voltage (drop) value. I'm pretty sure that I'm sending at least 20mA through the leds on the outer ring. I'll check my calculations out on paper and scan 'em in for you this weekend. I hope this helps -Josh

[avin]

Hello again, so i end up using a Green LED to drop the voltage down to 5V into those IC :P and here is some picture that you wanted to see. The routing is very messy :P i was too lazy to fix it so i let most of the work be done by auto-route.

[T3h_Muffinator]

OH MY! I'm loving the progress. This is REALLY cool. I just can't believe someone is actually replicating my work. I really want to thank you! Btw, Could I have the schematic "print" that you used to etch the board? I'd be willing to team up with you and make different designs as well. PCBs are MUCH easier than perf boards. This is just SO cool. Thank you thank you thank you! I really hope Mei Ling likes the heart! Send her my regards ;) -Josh Gordonson p.s. If you need help with anything, no matter what, ever again, just drop me a line either through PM or [e-mail] p.s.s. You have no clue how happy I am to see someone replicating my Instructable. You, my friend, are SOOOOOOO AWESOME. Okay, I'm so excited that my hands are quivering.... THANK YOU!

[avin]

Your instructables was a good idea :) i like it hehe