Here's a simple DVM made from an Arduino VIDOR 4000.
A potentiometer is placed in between VCC and GND with the wiper connected to analog input A3.
The value of the analog input is read and then shown through the HDMI to a monitor screen.
The arduino example code for showing the Arduino logo was modified for this project.
Here is the code listing:
//MKR VIDOR 4000 Simple DVM
//R. Scott Coppersmith
//Last Edit 16July2019
#include "VidorGraphics.h"
#include "Vidor_GFX.h"
Vidor_GFX vdgfx;
int analogPin = A3; // potentiometer wiper (middle terminal) connected to analog pin 3
// outside leads to ground and +5V
int val = 0; // variable to store the value read
void setup() {
// Initialize the FPGA
if (!FPGA.begin()) {
Serial.println("Initialization failed!");
while (1) {}
}
delay(4000);
// Fill the screen with a white background
vdgfx.fillRect(0,0,640,480,vdgfx.White());
}
void loop()
{
while (1) {
delay(200);
val = analogRead(analogPin); // read the input pin
vdgfx.fillRect(50,50,250,180,vdgfx.Yellow());
vdgfx.text.setCursor(50,150);
vdgfx.text.setAlpha(255);
vdgfx.text.setSize(4);
vdgfx.text.setColor(vdgfx.Blue());
vdgfx.println(val);
}
}
Video of operation:
https://www.element14.com/community/videos/29879
To convert counts (14-1023) to voltage (0.0 vdc to 3.3 vdc) change val from int to double and add this line of code after reading the analog input:
val = (val-14)*3.3/(1023-14); //convert to voltage 0-3.3vdc