I am using red LEDs with an operating voltage of 1.85V and operating current of 20mA.Originally Posted by ericgibbs
Too bad they don't make a 100 unit tall lite-brite. It's just black paper with a bulb behind it. Would have been bog easy to operate. Just add colored plastic pegs and they automatically light up.
How tall is that rocket??
An easy way to do the LEDs would be bar graph displays as I posted before.
neat, clean and not really expensive.
you could insert into dip sockets mounted on copper clad perboard.
you could light two at a time if the leds are too small.
thinking one 10 pos dip switch and a 10 pos rotary switch is all you need.
a power supply for each section of ten.
that picture of the building sure cries out bar graph displays
Hi,
just forget about my design. I didn't realize you want all LEDs on (bargraph).
Anyway, using 5mm LEDs you could try to get low current types of 2mA current.
In other words, any wall wart from 200mA output and up will suffice for the application. (Adjust LED current limiting resistors to the output voltage.)
Using the minimum of 200mA output you could probably use the power supply to perform fireworks when the one million is done.
Good luck with the project.
I can already imagine the diabolic grin in your bosses face switching from 10,000 to 1,000,000 with a single switch.
You can minimize this effect by connecting the switches as shown in the attachment.
Regards
Boncuk
Proper Planning Prevents Piss Poor Performance
I like the Lite-Brite idea best - no LEDs, one AC bulb and 100 pegs. You could build an LED rainbow with that kit, as the scale progresses. Perhaps your job depends upon you working under pressure, not designing innovative electronic displays.
Actually in hindsight the lite-brite version would probably be the easiest. A florescent tube running the height, perhaps a diffuser to keep the light even, some black construction paper and a strip of wood or plastic with 100 holes drilled in it.
Can you still buy lite-bright to get the pegs?
Last edited by blueroomelectronics; 8th September 2009 at 04:53 PM.
wonder how professional the lite bright idea??
nice idea but if you were a prospective client what would you think if you saw a light bright display in a bussiness enviroment?? just my opnion
I think I have a power supply solution on using LEDs
multiplexing using a 4017, 10 transistors, and a 555
using bussed resistor networks, dip sockets and project perf boards along with bar graph displays
look at mouser # 604 DC20/205RWA
has 20 ledsin a dip package measuring 50.7mm long 75mw 9000-31000mcd
ALL dip sockets for switches, ic's, leds. and resistors.
couldn't get any easier
to save you time
ALL in dip packages except the 2n2222 transistors.
then itsall point to point wiring = simple, easy
here is a parts list if interested mouser.com
hope this helps as the clock is ticking
512-LM555CN .31 clock
595-CD4017BEE4 .43 multiplex ic
604-DC20/20SRWA $4.29 x 5 led display 9.85" tall
652-4114R-2LF-220 .58 x 10 14 dip resistor networks
653-A6T-0104 $1.60 x 10 dip switches
517-4808-3004-CP .16 8 pin socket
571-1-390261-4 .20 16 pin socket
517-4820-3000-CP .22 x 10 20 pin sockets
571-1-390262-5 .39 x 5 40 pin sockets
863-P2N2222AG .20 x 10 2n2222 transistors
Ok I have put together this circuit based on what ericgibbs has posted using a 74HTC164. It only includes the control circuit and the resistors for the LEDs. Each of the green pads will go to an LED. I have a couple of questions...
1) Have I done this right?!
2) What do I do with all the clock inputs?
3) Will this circuit definitely do what I need ie - count up by one everytime the button is pressed whilst keeping all the previous LEDs illuminated?
4) What power supply will I need if I am using 1.85V red LEDs with a 20mA operating current?
If I can't get this circuit sorted by the end of today I think I'm going to have to go down the dip switch route...
Thanks
Leo
Sorry forgot to add the attachment....
At 20mA per led for 8 led's the specified current rating and dissipation of the 74HCT 164 will be exceeded.
A suitable shift register would be TPIC6595.
Compared to the bit switch solution the S/R will be expensive and lack memory retention at power off.
Eric " Good enough is Perfect "
I will NOT answer PM's requesting technical help, please use the Forum
PIC tutorials: Nigel's www.winpicprog.co.uk/ Bill's: www.blueroomelectronics.com/
Link to my Articles: http://www.electro-tech-online.com/a...icgibbs-55450/
It also can't decrement if you press the button too many times.
Thats exactly what I was thinking
too many presses and the "SB1 rocket" would act like Berni Madoff
If the op decides to go with the 74164, would my proposal of multiplexing using a 4017 be an option to limit the LED current?
Sometimes the trees get in the way of seeing the forest
I vote for the dip switches. Easy, cheap and the entire circuit could be crafted in 2 hours using all dip sockets.
Bargraph displays, dip switches, resistor arrays.
Heck the resistor arrays alone would save 90 solder connections. 200 (2 per resistor vers 11 per array)unless you go with 16 pin arrays (14 resistors per dip package)
The displays if not long enought, just double the number of displays.
each 20 led display is 50.7mm long x 5 =9.84 inches. If you want a 21inch display (2 LEDs per quota amount no big deal. The displays are end stackable.
Just need to speed up the multiplexing clock.
the op has 10 days left!!
A 5V @ 1.2A switchmode wall supply is common and cheap. 100 LEDs at 10mA each is only 1A.
But how bright?
at 10 ma??
I like bright LEDs
lets try 50ma ---lol
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