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I need help building a circuit for a simple LED display. I need it to count up to 99. So a 2 pannel LED screen would work. The hard part is that I need it to start at zero and then anvance one digit every time you press a switch. It would also be nice to have a reset button. Some help would be greatly appreciated. <p>P.S. I found a simple schematic of an event counter used with a camera to see how many shots you have taken. Here's a link..
http://www.jesseshuntingpage.com/images ... ematic.jpg<p>Please help me! Thanks

Someone PLEASE help me! I really need some help!

What tools do you have at your disposal? My first intuition would be to design a solution in verilog and use an inexpensive programable logic device (PLD) to solve the problem. Another equally good solution, depending on your experience and acccess to development tools would be to use a microcontroller.
If you don't have either of these options, you might have to consider using two 4510 BCD up/down counter and supplying their outputs to two 4511 BCD-to-7-segment decoder/drivers. Supplying an edge to the clock pin of the first 4510 increments its count by one. The second 4510 is cascaded onto the first as described here:
http://www.doctronics.co.uk/4510.htm
There is also a link here to a page describing the connection of the 4510 to the 4511.

BTW if you dont have access to the development tools necessary to solve the problem with PLD or a microcontroller, it's easy to get started!<p>Lattice Semiconductor (http://www.laticesemi.com) offers free development software and an Engineering Development Kit runs about $100 on:
http://www.arrow.com<p>Atmel (www.atmel.com) has support for avr-gcc, an open-source c-compiler:<p>http://medo.fov.uni-mb.si/mapp/uTools/<p>http://home.overta.ru/users/denisc/<p>That means FREE. The devel kit (STK-500) was $80 last time I checked, though it comes with two very capable microcontrollers.<p>Microchip (www.microchip.com) is the manufacturer of the ever-popular PIC microcontroller and offers a line comparable to Atmel's, although their programmer costs about $100. The programmer and chips can be ordered from their site. If you require a C compiler, Custom Computer Services (http://www.ccsinfo.com) offers a C-compiler for $100 for the PICmicro controllers.<p>[ July 05, 2002: Message edited by: bobsRAC ]</p>

Well thank you for the feedback, except I am a beginner at this and I was hoping to have a simple schematic that I could make the counter from. I also do not want to spend very much money. Can anyone help me...

The approach using the 4510 and 4511 is about as easy as it gets. The URL in my first post shows the cascading of the two 4510s about half-way down and the connection of the 4510s to the 4511s at the bottom of the page. Here's the URL again (just in case):<p>4510 and 4511 usage<p>Digi-key (www.digikey.com) prices<p>--------------------------------- <p>CD4510BE -- $0.75<p>CD4511BE -- $0.75<p>2-digit 7-segment display -- $3.40<p>spst no momentary pushbutton -- $2.50<p> --------<p> $7.50

Sir "Web-Tekkie":
Since your profile doesn't tell me who U is....and how could we not respond to a request like:
<<Someone PLEASE help me! I really need some help! >> ,but at least you haven't
fallen and can't get up..hi hi.
You didn't tell us the use for which this is intended....personally I'm blind to it, but within the realm of provided data and........ just having to guess.
First, power consumption is not too important if U're OK with LED utilization.
My first thought of utter simplicity would be for you to rush...don't walk ..down to your
Dollar Store and pop down Ur $1 and get a pocket calculator...go for it ...get the Hi-Tek
LCD display vice LED (current hog). Confirm that it uses the rolling K constant mode by
[Clearing] then hit [+] then hit [1]..display shud show {1}....then hit[=] and the display
shud stay on and show {1} as your first entry on the [=] key and the next time U press
[=] it shut read {2}.. the second time of entry on the [=] key on up to 99 where the
[clear] wud reset, until you reinstate the initialization of [+] [1] then the [=] takes the
count entry. The only aberration is the display count not being on Zero initially prior to the
first count but after that its on count ,til 99..or more.......,even with no power worries
about leaving it on and holding the count. If you get the batt powered model, if U get
the solar model, it could potentially drop off. Access to the keyboard and two sets of fine
Kynar wire to get the [=] and [Clr] keys to Ur Count and Reset pushbuttons...considering
U can , probably not too frequently, enter the [+] and [1] keys . Wud this work for U ?
The second solution was some surplus counter boards that I had, and was salvaging the
45xxx series 3 dig counter on a chip from them but they later switched to a custom chip .
They gave me a eng sample of the nu config but I passed on it. It did count up 1 digit at
a time and cud be reset to 0. It used a red LED display(Current Hog) and had the small
1/8 " hi digits. If I can still find it... I have no need for it.
73's de Edd
[email protected] (Interstellar~~~~Warp~~~~Speed)
[email protected] (Firewalled-Spam*Cookies*Crumbs)

dudes ! theres already commercial ones made for cheap.. they are in many shops / stores., you know,,, the take a # and wait till they call you,, and usually they have a digital display on the wall so you can see your # is up,, most baskin robbins here have them,, take a look in your local area,, maybe thats a better hint for you .. good luck,,`