PedalSHIELD UNO Please Help with reading a schematic arduino UNO

[jimitrader]

I need help reading a schematic for the pedalSHIELD UNO. ?
I am bread boarding this project and am confused by the schematic? I says to connect VCC+ @ U1A #8 and U1B #8 ? how can this be possible?

page link:
https://maker.pro/projects/arduino/arduino-diy-guitar-pedal/

thanks JL

[jimitrader]

[EBK]

U1A and U1B are two halves of the same chip.  8 pins total.

In other words, you only connect pin 8 once.

[jimitrader]

so connect (power supply) VCC to pin 8 


what about C11?

[EBK]

C11 gets connected between pins 4 and 8.
Ignore the fact that your power supply pins are printed twice in that schematic.

[jimitrader]

thanks! I will give it a try...I will post you back results!! thank you...JL

[ElectricDruid]

+1 what EBK said. That's dead right.

Not only are the power supply pins printed twice, but they're printed once the right way up and then the other time the wrong way up! Arrgghh!

Not surprised you found it a bit confusing.

T.

[jimitrader]

 my new question is about the ground ..since i am on a breadboard without a uno shield i am wondering about the ground points. are they all connected together ? thanks JL

[jimitrader]

also which is the wrong layout mentioned? 'wrong way up"

[ElectricDruid]

my new question is about the ground ..since i am on a breadboard without a uno shield i am wondering about the ground points. are they all connected together ? thanks JL

Yes, they are. Anything with the same symbol should be connected together.

T.

[ElectricDruid]

also which is the wrong layout mentioned? 'wrong way up"

No, it's not a "wrong layout" - it's technically correct as drawn. I just meant that I don't like the way they've used an op-amp symbol with power pins attached, so when the symbol is flipped to reverse the positions of the +ve and -ve inputs, the power pins flip too - which gives you +V at the bottom and ground at the top. Ugh.

For me, higher voltages should go at the top, and lower voltages should be lower down - logical, right? It's just a convention but it helps make stuff more readable.

Tom

[jimitrader]

What is the reason for the Virtual ground?

I am going to try and make a fritzing file image to show what i have hooked up..maybe someone could see where i went wrong...thanks JL

also in the schematic it shows led cathode to ground...if i put it that way it doesn't work? if i flip it the 'wrong way" it works...that seems strange to me...;-)

[EBK]

The LED cathode should go toward ground.  If it only works in reverse for you then one of the following could be true:
1)  You have your power supply hooked up backwards,
2) You are misidentifying the LED leads, or
3) You have some other error in your wiring.


The virtual ground is there so the op amp's input will be between its positive and negative power supply values.   It gives a DC shift to your AC input.

[jimitrader]

so does the virtual ground go to ground? I think this might be my problem area...i am not to sure about that part of it. thanks for all the tips...JL

[EBK]

Just so I'm clear, when you say "virtual ground", are you referring to the spots labeled "2v5" in that schematic?

[jimitrader]

no i hooked that to R2 ? and then connected GND TP - TP2 to the main ground? is that wrong?

[EBK]

TP1 and TP2 are just labels for "test points".  If you connected both to ground, then you are shorting your power supply.  Only TP2 is ground.  TP1 is +5V.

[jimitrader]

TP1 and TP2 are just labels for "test points".  If you connected both to ground, then you are shorting your power supply.  Only TP2 is ground.  TP1 is +5V.

I connected only tp2 to ground (where the ground symbol is) i put TP1 5v in from Arduino board then 2.5 to r2.

[jimitrader]

TP1 and TP2 are just labels for "test points".  If you connected both to ground, then you are shorting your power supply.  Only TP2 is ground.  TP1 is +5V.

I connected only tp2 to ground (where the ground symbol is) i put TP1 5v in from Arduino board then 2.5 to r2.

then for the Arduino connectors I put digital ground -jumper-ed over to analog ground... then analog ground #2 to the breadboard ground..

[jimitrader]

I am not having any luck with fritzing