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...
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.
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!!
Well the OP better get cracking with whatever design he plans to use. I like the marble idea but I suspect they would get pretty dim after it started filling up.
My last car (Ford Scorpio) had a max speed of 200km/h resulting in an 8 hour trip from Hamburg to Munich, which meant a bad ratio of travel time vs. work time. (very often a one or two hour job to do)
After tuning it made 280km/h ensuring a travel time of not more than 5 hours.
supposly has the least traffic fatalities per mile than any other highway in the world
and an unlimited speed limit to boot
go figure.
but then I guess you never drove on a S. cal freeway
max speed is like 30 if your lucky.
Wow! And I thought Bill's idea was minimalist genius.
Add a 5w bright red laser shining up from the bottom of the tube to make the marbles glow (and maybe a brightness adjust knob) and that would be a fully workable and visually beautiful display.
that drops a marble into the tube, makes the laser blink then an alarm sounds!!
sounds like a great idea
lets see you need a pic with software then a 2803 to drive the servo motor that controlls the elevator that gathers up a marble or more as needed then transports the marble/s up to the top of the "SB1" rocket and deposits them
the laser then blinks by way of a pic comand.
have a light sensing cell so at night when nobody is at work, the laser shuts off to save energy. Of coarse in the pic code you need to puyt the pic in sleep mode.
the op had better get cracking and maybe Bill will program the pic for the op
LOTS TO DO. only 8 days left.
sure hope parts have been ordered.
are you sure a 5W laser is big enought?
maybe program the pic to measure the weight of the marbles and switch on a second and/or third laser according to the weight/# of marbles
LOL
going the pic route.
would be a simple up count code with option to count down if need be.
actually the pic would have been easier maybe than the dip switches.
My question is why did the op start throwing 74164's into the mix?
going from A to B via C, D, and E. IMO
I really like the laser idea could be exciting