# Voltage Offset - Guitar -> Teensy

#### Ec452

Joined Feb 21, 2024
2
I am working on a project to add a tremolo effect to a guitar signal through a teensy. The dynamic range of the guitar is 900mv to -900mv. The teensy's ADC pin reads voltages from 0 - 3.3v. I have a non inverting pre amplifier that is outputting a simulated guitar signal ranging from 1.5 to -1.5 volts. What is the easiest way to offset the signal 1.5 volts.

#### crutschow

Joined Mar 14, 2008
34,834
What is the easiest way to offset the signal 1.5 volts.
Use a capacitor to couple the signal with the cap output connected to two voltage divider resistors between your DC supply voltage and ground.
Select the resistor values to give 1.5Vdc.

What supply voltage do you have?

#### Ec452

Joined Feb 21, 2024
2
I was trying to simulate the max electric guitar input with a 900 mv sinuisodal input. I am running this on simulink. I was trying to figure out how to shift my output efficiently 1.5v to be read by a teensy adc pin. I can send the simulink .slx file.

#### Attachments

• 73.5 KB Views: 11
• 290.9 KB Views: 11

#### DickCappels

Joined Aug 21, 2008
10,246

#### MisterBill2

Joined Jan 23, 2018
19,389
In post #1 the output of the guitar was +900 to -900 mv= 1.8 v Peak to peak.That is not the dynamic range, that is the output voltage. To produce the DC offest so that the waveform midpoint is 1.5 volts, use the circuit shown in post #4, but make both resistors 20K ohms instead of 2K , and change the 10 volt source to 3 volts.

In my career of many years I have not come across a "teensy" , so I can not provide any help there.

#### nsaspook

Joined Aug 27, 2009
13,545
In post #1 the output of the guitar was +900 to -900 mv= 1.8 v Peak to peak.That is not the dynamic range, that is the output voltage. To produce the DC offest so that the waveform midpoint is 1.5 volts, use the circuit shown in post #4, but make both resistors 20K ohms instead of 2K , and change the 10 volt source to 3 volts.

In my career of many years I have not come across a "teensy" , so I can not provide any help there.
You never used teensy(-weensy) as a kid for something small or tiny? Here it's the name of a type of controller small board.

#### MisterBill2

Joined Jan 23, 2018
19,389
You never used teensy(-weensy) as a kid for something small or tiny? Here it's the name of a type of controller small board.
Nope, never did. And in addition, when trying to provide accurate communications with folks who may not use the same colloquial words, I do my best to stick with the more technically appropriate terms. Recently I confused somebody by using the terms "upstream" and "downstream", to which another individual took great exception. It seems that they have never seen a stream.

#### nsaspook

Joined Aug 27, 2009
13,545
Nope, never did. And in addition, when trying to provide accurate communications with folks who may not use the same colloquial words, I do my best to stick with the more technically appropriate terms. Recently I confused somebody by using the terms "upstream" and "downstream", to which another individual took great exception. It seems that they have never seen a stream.
Sure, those that know the subject well are blind to those that don't. Imagine what's lost in language translation.