Check my newbie circuit. Lighting leds in sequence with delay

Thread Starter

replicaprops

Joined Jul 1, 2017
28
I'm not sure if I designed this correctly, and I wanted some more eyes on it. Obviously, i'm a novice at circuit design, and I have to use the pcb section of fritzing so I can visually see what I'm connecting.
The idea of this circuit is to press the switch, and have the led zones light up in sequence. I read that a resistor in line with a capacitor will accomplish this. So when the magnetic reed switch on the underside of the pcb is close, the power goes to the R and C on zone 1. 0.5 second delay then the leds in zone 1 turn on. 0.5 seconds later zone 2 finally 0.5 seconds later zone 3.
So does this circuit look correct? If put ground seeds on all the leds and capacitors as well as the battery.
Thanks for any comments in advance.
 

Attachments

Thread Starter

replicaprops

Joined Jul 1, 2017
28
I've also read somewhere that the addition of a transistor between each zone will help with the timing delay i'm looking for.
 

dl324

Joined Mar 30, 2015
11,506
Clipped, edited schematic for convenience:
edit.jpg
I've also read somewhere that the addition of a transistor between each zone will help with the timing delay i'm looking for.
The circuit won't work. By having capacitors in series with the supply, there is no DC path for current.

What is your complexity budget?
 
Last edited:

dl324

Joined Mar 30, 2015
11,506
I am willing to try anything, but my pcb enclosure is a 2.5 inch octagon 1/4" thick. This is what I am trying to replace in my product line.
Post your ideas and members will help you. Since this seems to be a commercial product, don't expect free design services.
 

Thread Starter

replicaprops

Joined Jul 1, 2017
28
Post your ideas and members will help you. Since this seems to be a commercial product, don't expect free design services.
I have no problem paying someone for help. I just want to get a design that works, fits and I can send off for pcb production.
 

dl324

Joined Mar 30, 2015
11,506
I have no problem paying someone for help. I just want to get a design that works, fits and I can send off for pcb production.
Contract design services aren't cheap and it will involve more than you think because the engineer who designs it would be responsible for every aspect of the design and potential liabilities could be large.
 

Thread Starter

replicaprops

Joined Jul 1, 2017
28
Contract design services aren't cheap and it will involve more than you think because the engineer who designs it would be responsible for every aspect of the design and potential liabilities could be large.
Do you think this design is all that complicated? Seems i'm pretty close, just missing a bit of understanding how to trigger the events I want to trigger.
 

Thread Starter

replicaprops

Joined Jul 1, 2017
28
No, I don't think the design is complicated.
You aren't close. If you were close, I'd be giving you free advice on how to finish.
Okay, well I appreciate what you have told me. So how much would you like me to pay you for the correct schematic?
 

AnalogKid

Joined Aug 1, 2013
8,590
Magnet to reed switch = power on
0.5 s delay (all dark)
first LED bank comes on for 0.5 s

Then what?
Bank 1 goes dark, 0.5 s delay, bank 2 goes on.
or
Bank 1 goes dark, bank 2 comes on immediately.
or
Bank 1 stays on, bank 2 comes on
or or or or

The schematic has too many errors to describe in detail. Please give a detailed step by step description of the intended operation. And, what happens when the first pattern is complete. In your schematic, all LEDs are off and they stay off until power is removed for around 10 seconds. If your circuit worked the way you thought it did, then if power is reapplied too quickly the capacitors don't have enough time to discharge and the timing will be all wrong.

ak
 
Last edited:

Thread Starter

replicaprops

Joined Jul 1, 2017
28
Magnet to reed switch = power on
0.5 s delay (all dark)
first LED bank comes on for 0.5 s

Then what?
Bank 1 goes dark, 0.5 s delay, bank 2 goes on.
or
Bank 1 goes dark, bank 2 comes on immediately.
or
Bank 1 stays on, bank 2 comes on
or or or or

The schematic has too many errors to describe in detail. Please give a detailed step by step description of the intended operation.

ak
After bank one comes on, 0.5s later bank 2 comes on also, then 0.5s later bank 3 comes on as well. All three banks stay on until power is cut.
 

dendad

Joined Feb 20, 2016
3,602
You could use a bar graph display driver, and have a capacitor slowly charging in the input.
http://www.learningaboutelectronics.com/Articles/LM3914-dot-bar-display-driver-circuit.php

or the Dreaded Arduino and driving an I2C Port Expander if you need more LEDS than the Arduino can drive.
I for one would go the Arduino way. For a start....
https://www.tutorialspoint.com/arduino/arduino_led_bar_graph.htm
There are lots of examples of this sort of thing on the net and it would be a good idea to have a go to see if you can follow the guides and modify the code to give you what you want.
On this forum you can get help but really it is not up to us to do it for you but to encourage you and help you to learn how to do it yourself.
This is a pretty good project to do just that.
Keep at it.

Oh, have a look at the tutorials here too. I've found them pretty good and am starting to use them in the electronic classes I volunteer to give.
http://www.learnabout-electronics.org/
 
Last edited:

Thread Starter

replicaprops

Joined Jul 1, 2017
28
You could use a bar graph display driver, and have a capacitor slowly charging in the input.
http://www.learningaboutelectronics.com/Articles/LM3914-dot-bar-display-driver-circuit.php

or the Dreaded Arduino and driving an I2C Port Expander if you need more LEDS than the Arduino can drive.
I for one would go the Arduino way. For a start....
https://www.tutorialspoint.com/arduino/arduino_led_bar_graph.htm
There are lots of examples of this sort of thing on the net and it would be a good idea to have a go to see if you can follow the guides and modify the code to give you what you want.
On this forum you can get help but really it is not up to us to do it for you but to encourage you and help you to learn how to do it yourself.
This is a pretty good project to do just that.
Keep at it.

Oh, have a look at the tutorials here too. I've found them pretty good and am starting to use them in the electronic classes I volunteer to give.
http://www.learnabout-electronics.org/
I wish I had the room for a arduino. Thanks for the suggestions.
 

Thread Starter

replicaprops

Joined Jul 1, 2017
28
Okay, I appreciate everyone advice. I ended up hiring an engineer to design this for me. I had hoped this was a simple enough design that those with knowledge would educate me. I thank you for the time you all took to speak to me.
 

AnalogKid

Joined Aug 1, 2013
8,590
Why does one bank have 6 LEDs while the other two have 4?
Now that the task description is clear, this is a more simple circuit than I originally thought.
One CD40106 CMOS Schmitt hex inverter
three 2N7000 MOSFETs as LED drivers
three 470K Rs
four 1 uF Cs
plus the LEDs and resistors.

Your largest misunderstanding is that an R-C delay is not done with the R and C in series. The R is in series between the two stages, but the C is a shunt leg, connected to either GND or Vcc depending on the logic polarity needed. The second problem is that the three stages cannot drive one another in series without some kind of level-sensing buffer between them.

Where are you located?

ak
 

Colin55

Joined Aug 27, 2015
519
"Contract design services aren't cheap "

We are baaed in India and charge 25 cents per hour. I hope you can use our services.
 

Thread Starter

replicaprops

Joined Jul 1, 2017
28
Why does one bank have 6 LEDs while the other two have 4?
Now that the task description is clear, this is a more simple circuit than I originally thought.
One CD40106 CMOS Schmitt hex inverter
three 2N7000 MOSFETs as LED drivers
three 470K Rs
four 1 uF Cs
plus the LEDs and resistors.

Your largest misunderstanding is that an R-C delay is not done with the R and C in series. The R is in series between the two stages, but the C is a shunt leg, connected to either GND or Vcc depending on the logic polarity needed. The second problem is that the three stages cannot drive one another in series without some kind of level-sensing buffer between them.

Where are you located?

ak
Sounds like you know what is needed. I appreciate you sharing the knowledge you have. I am in Texas. I make models as a hobby and sell them online. This was for one of the models I make.
 
Top