Need help designing a counter circuit. (I don't have a lot of experience designing circuits)

Thread Starter

Spencer001

Joined Jan 4, 2020
1
I am currently designing a counter circuit, however, i keep running into issues and a point in the right direction would be greatly appreciated.

Components I want to include:
- a 7-segment display and 4026
- a PICAXE and/or a 555 IC (the PICAXE would be used to turn the device off without resetting the 7-segment display)
- an LED to show that the device is on
- three switches: one to reset, one to turn off/on the device and one to add to the count
- possibly a piezo buzzer to read the count on the 7-segment display (?)

I have attempted to make this circuit (it is attached) but did not get very far. Again, any advice would help, thanks.Capture.PNG
 

wayneh

Joined Sep 9, 2010
16,399
I am currently designing a counter circuit, however, i keep running into issues and a point in the right direction would be greatly appreciated.

Components I want to include:
- a 7-segment display and 4026
- a PICAXE and/or a 555 IC (the PICAXE would be used to turn the device off without resetting the 7-segment display)
- an LED to show that the device is on
- three switches: one to reset, one to turn off/on the device and one to add to the count
- possibly a piezo buzzer to read the count on the 7-segment display (?)

I have attempted to make this circuit (it is attached) but did not get very far. Again, any advice would help, thanks.View attachment 196095
I haven't studied your schematic so my comments are strictly about general troubleshooting.

Divide and conquer. Start with getting each individual component working the way you think it should. You may have to substitute a manual switch to isolate one component from another. Make sure your power source is clean and supplying what you think it is. Don't forget to use bypass capacitors on the ICs, and keep your wires short and cleanly arranged.

When you come back, explain what you mean by "did not get ver far". Show some pictures, maybe. It's hard to help remotely without a lot more detail.
 

dl324

Joined Mar 30, 2015
11,452
Welcome to AAC!
I have attempted to make this circuit (it is attached) but did not get very far.
For starters, tell us what "did not get very far" means.

One obvious problem is that you're asking the outputs to source more current than they can. This is the recommended circuit for driving LEDs:
clipimage.jpg
Though I would have used PNP transistors, with signal inversion, for the common cathode configuration.

If you lower segment current, you might be able to use CD4050 buffers.
 

ci139

Joined Jul 11, 2016
1,696
your pin-2 on 555 should be pulled down for "Set" . . . and just incase dissconnect the pin-7 DISCHARGE from anything
 

jbeng

Joined Sep 10, 2006
74
I agree with wayneh in that you should divide & conquer. Make sure the individual parts of your circuit are working properly, then get them working together as a system.

First thing I see in the circuit you show is that the 555 timer circuit needs proper power and ground connections. It will also need a resistor and capacitor to form a timing network to make a pulse. In the datasheet at the following link, find section 7.4.1 where it shows how to configure a 555 for monostable operation, which is what I think you are trying to do.
LM555 datasheet
 

AnalogKid

Joined Aug 1, 2013
8,575
(the PICAXE would be used to turn the device off without resetting the 7-segment display)
Your question needs some work. What do you mean by this? "Turning the device off" and blanking the display so the number is not shown are two entirely different things.

ak
 
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