delabs Circuits

Thursday, September 18, 2014

Up-Down counter-timer

(A question answer thread of delabs.net, nearly a decade old)

Presettable Up-Down counter-timer-Question   

I am looking for a schematic for a pre settable Up/Down counter that I can build for my church. It needs to be 5 decades. From 0:00:00 to 9:59:59. I ran across your web pages while searching for such a schematic. Can you help me out?

EE



Presettable Up-Down counter-timer-Answer

It appears from the "9:59:59 " you have mentioned, what you need is a timer.It it a count up and count down timer you need, like a clock ?

Can you explain to me how you plan to use this circuit in the church.Visit the links below and see if that is what you want.

delabs


Presettable Up-Down counter-timer-Reply 

Thanks for the links. What I need this count down timer for is to allow speakers at the church to know how much time is remaining of their presentation. All of our speakers are taped for later use or review. The speakers giving the presentation usually go over their time limits for the audio tapes. With this unit I am trying to build time can be entered by preset thumbwheel switches. The counter is then started and times out when the counter reaches 0:00:00.

What makes this count down timer different is there will be two seperate displays. A one inch set of seven segment LED's will be in the main console with the rest of the logic. There will also be a 2.5 inch set of seven segment displays remotely connected (anout 3 feet away). The large displays will be what the speakers will see. The small displays will be in the control booth.

I already have the following items gathered up. I am hoping to use these components if I am able. I have the MC14029, the MC14513, the Allegro UDN2597A (to drive the large LED's), the Dallas Semi DS32KHz time base, the MC14020, the MC14013, the large and small LED displays, and the thumbwheel switches (set to 9:59:59 maximum)

I also have some MC14011, MC14490 (Hex Debounce Switch Controller, MC14049, and the R's and C's necessary to complete the circuit.

Does this explain what I am trying to do? I think the MC14029 counters can be used to do all the counting and store the preset values. All I have to do is add the reset at 6 for the tens of seconds and the tens of minutes. However, I don't know how to connect the logic?

The DS32KHz, MC14020 and MC14013 will generate the 1 Hertz (1PPS) signal. That is about all I currently have. That is why I need some help

EE


Presettable Up-Down counter-timer-Answer

below are two circuits in pdf format see if they are ok see... Digital Circuits-2

Circuit 1 - Digital Timer Clock With Preset using Thumbwheel switch.


Circuit 2 - 1 Hz or 1 pps crystal clock using CD4060 and 32768 Hz Crystal.


They have not been tested much... The 4513 control pins 8-4-5-3 connections verify, as i did not get the datasheet.

the circuits will work as concepts are right, but some tweaks in R C values may be required.
the R C values can only be corrected if you have problem in making it work.

the main problem in the R C values may be related to "the reset at 6 for the tens of seconds and the tens of minutes". tell me what changes you may want. this is a presettable count down timer upto 99.59.59 hours.minutes.seconds

delabs