Short beep (from a hi latch)

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So you have "islands" of copper that are isolated from the rest of the ground plane because the router cannot find a path to completely connect the coppr plane. You have to fix this and have some choices to make. Adjust the track-to-track clearances so there is more room for the copper fill to pass thru and/or move traces to create room. This is sort of trial and error until the everything is connected.

I suggest if you have more board routing questions, move them to a different thread under PCB/simulation topic.
 
eTech said:
So to fix this, I've connected U2-RST to U2-Trigger.
Click to expand...
I appreciate this. i did not notice any issues but ill make the changes.
eTech said:
See this; 1N4148W
Click to expand...
Is the BYG23M not compatible? I can get them for .20 each. the 4148's are more expensive. Got to buy a large quantity. I can always use the through hole version if I have to. they are both very small.
EDIT: I found the ECAD for 1n4148w.
 
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Looks like its ok.
However, the 1N4148W is .21 at mouser. I'm recomending what I know will work...
 
Ive made changes to this project based on suggestions from newer posts on other topics Ive posted.
This is an all SMD project.
Moved bypass caps closer to IC components.
orientated and moved components to shorten track lengths.
resized power track to 25. Kept tracks same size (no narrowing or funneling)
physically routed ground track in addition to just relying on GND pours to connect nets.
moved components so GND pours create the maxim number of spokes.
RE-numbered components
Edited a few PCB symbols to help reference components

I know everyone has their opinions about how things are done and believe me i have taken everyone's suggestions into consideration.

 
Got two issues.
I completed a prototype. love the 3mm solder and ive learned that the boards need to be de fluxed so im posting that image so you can see my work.
Upon testing a finished board the beep is much longer than .5 second. Its now 3.5 seconds. And its much louder too. I remember you said a Resistor controlled the time but there were updates so it may not apply any longer. Regardless i used the same component values as outlined so i thought id compare my breadboard to see what i may have missed. Well i give. i mean ive compared and verified this thing to death and i see no problem. So im here asking for you to look at my board. Help me figure out what is wrong. Thank you.
BB Observations:
It does not beep on trigger press from 5.5v to 0v
It does beep .5 seconds (soft sound) on start up
SMD pin out is different that through hole.
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Soldered Board Observations:
It works. its just loud and beeps for 3.5 seconds
------------------------------------------------
Soldered prototype:

My BB (Attached)
Your Schematic:

My Schematic:
 

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ThomsCircuit said:
It works. its just loud and beeps for 3.5 seconds
Click to expand...

Hi

Back on post #32 you posted this:


Probably should have left it at 2.2 uf. It will beep alot longer if you changed it to 10uf.

BTW-R3 (your schematic) could be replaced with a 500k pot so the time will be adjustable (i probably stated that somewhere).
 
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eTech said:
Probably should have left it at 2.2 uf. It will beep alot longer if you changed it to 10uf.
Click to expand...
you are correct.
I have the 2.2uf and ive just made the one board. So i can make the adjustment on the next board.

If you could help me get my BB to beep id be able to understand / explain a few things. like why the bread board is so soft sounding and the beep was just about a second but my PCB is loud and longer 3 second beep. I like to get the two to behave the same so i could see what i did wrong.

Ive labeled a number of pins and values to help.
 

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Its fairly simple. ref: your schematic
1. The NAND gates "XOR" output is normally low and it outputs a short high pulse whenever the input changes state.
2. IC3 generates a pulse (low to high) with its pulse duration set by R3 and C4 (1.1 * R3*C4).
3. IC2 is held disabled by the low output signal from IC3 connected to the reset pin of IC2.
4. When IC3's output changes to high, IC2 generates a 2.3 Khz signal operating the beeper until IC3 returns low again.
5. Goto 1.
 
eTech said:
Its fairly simple. ref: your schematic
Click to expand...
Id like to buy a vowel.

The facts sadly are that i have misinterpreted the schematic in attempting to reproduce it on a bread board. I have tried for hours to find what i am missing but im not having any luck. I thought i was passed this but i can see i need more help.
The step process you provided is appreciated as ive wondered just how it does its function. It has not however helped me solve this puzzle.
 
I found 1 resistor that did not belong. I also changed out the 555 ICs. I replaced the 10uf with the 2.2uf.

The reason i increased cap to 10u was originally the duration was but a fraction of a second. With the changes ive made in locating errors the beep duration is now .5 seconds with the 2.2uf cap. So there is an improvement.
Now the sound level being low i think is because of the two 0.01uf caps i paralleled in efforts to reach the required 0.022uf. If I remove one of the caps the sound becomes very faint. So i believe that's what is setting the frequency.

ive taken a few readings with my MM. Surprisingly i can detect the pulse coming from pin 10 of the NAND. it is 5.5 volts when in ready mode and it pulses when the input changes state. I cannot tell if it goes up or down in voltage but it does pulse.
That may be a problem. i thought it went from low to a brief pulse. Not 5volts to a pulse.

Needless to say it still does not beep

Im determined to correct this because i don't think i ever had it right (BB) to begin with. You were so gracious to help me create it so i want to get it right. please continue to assist me.

Thank you
 
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Ok....are those timers each LMC555?

If so, the LMC555 does not have enough power to drive the buzzer. They must be LM555 or NE555.

Do you have an accurate schematic for your breadboard? If not, that is the first thing we need to successfully troubleshoot the circuit.

Can you take a good photo of the whole breadboard and orient the BB so that the input is at left and buzzer (output) is at right....just to make it easier to compare it with the schematic.

Once you do the above, I will review and compare the circuit with the breadboard.
It shouldn't take too long to get it working....
 
Yes...the 0.022uf cap and R4,R5 set the frequency to 2.3khz
.
Your description sounds like the NAND circuit is doing what its supposed to do..except pin 10 should be low and briefly go high whenever input pin 1 changes from low to high or high to low.
ThomsCircuit said:
Needless to say it still does not beep
Click to expand...
That is either because the timer is the wrong part and should be LM555 or NE555, or, the timer output frequency is not correct, or the buzzer in different than what we think it is.

But one thing at a time....
 
eTech said:
If so, the LMC555 does not have enough power to drive the buzzer. They must be LM555 or NE555
Click to expand...
Yes. I do have NE555. I'll change them
eTech said:
Do you have an accurate schematic for your breadboard? If not, that is the first thing we need to successfully troubleshoot the circuit.
Click to expand...
I believe I do. Being that my PCB works I must have. And the 555 timers are NE on the PCB so that would explain the sound level increase.
eTech said:
Can you take a good photo of the whole breadboard and orient the BB so that the input is at left and buzzer (output) is at right....just to make it easier to compare it with the schematic
Click to expand...
Will do.
All of this explains what I wanted to know. Ill get the photo up later on today. Thank you E!
 
I changed the 555 from LMC to NE and the BB functioned as it should. I than applied the change to the PCB and it worked the same as the BB.

I now know what the C is in LMC is. CMOS. I mean i knew it before i just thought the CMOS version was superior to the older (non CMOS) types but i see (no pun intended) they all have their place.
In my first project i did with ETech i was instructed to get the CMOS version of the 555. I just assumed they were better but now i realize that the 555 was outputting to a darlington driver so that may have been the reason. This project outputs to a buzzer so the LM555 would be needed unless i utilized a transistor.

There is more to explore of the 555 and I have tried to understand it but nothing beats a real example.
That explains why my BB version was so soft sounding as i just happened to select to 555's that were LMC where my PCB used SMD 555's that were NE style. As far as why my BB produced a shorter beep is unknown but i did mis-interpret the schematic to the point where it did function but just not correctly.
Thank you again for your help. I have learned quite a bit here.
 
Just want to be sure i understand this correctly.
TTP223 had a max voltage of 5.5V. at that voltage It will output a high latch voltage of about 4.5 volts on pin 1. Its output is defined as CMOS. If im using the TTP to trigger a NAND (CD4093B) which is also defined as CMOS i do not need to utilize a transistor to ramp up the voltage like i did to drive an LED and a small 5V Fan. I can just connect them directly.
 
That's correct. CMOS devices draw almost no current. They are voltage sensitive devices however, so its important that the input voltage transitions past 70% of the supply voltage for it to be reocognized as a high state and 30% to be recognized as a low state. So, for example, if the NAND gate has a power supply of 5V, the voltage to the input pins has to transition past 3.5v (going high) or 1.5v (going low) to be recognized as a change of state at its input.
 
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