Tiny Scope for Arduino

Features

• Configurable ADC speed for sampling rates from 10KHz to 300KHz (on UNO)
• Auto grid on time base from 2ms to 50us (on UNO)
• Vmax calibration and 3.3-5V detection using internal reference
• 0V auto trigger
• Display minimum-maximum voltage of captured signal
• Square waveforms are displayed properly
• Auto voltmeter mode when input is steady

The screenshots below are on a two-color display (yellow/blue).

Voltmeter mode is automatically switched on with a steady voltage signal (when it would be represented by a flat line).

Requires: Arduino UNO R3 or Teensy USB board and Monochrome 0.96" 128x64 OLED graphic display (SSD1306 driver)

Connections

• OLED VCC - 3.3V
• OLED GND - GND
• OLED SCL - A5 or SCL (Teensy SCL0 pin 19)
• OLED SDA - A4 or SDA (Teensy SDA0 pin 18)
• PROBE WIRE - A1 (defined in tiny_scope.ino) (Teensy pin 15)
• BUTTON - D7 button to GND

Testing

• A1 to 5V should display 5.00 V
• A1 to GND should display 0.00 V
• A1 to D9 (Teensy pin 9) should display a square wave (PWM) with >2ms period and >0.5ms pulse
• A1 to D5 should display a square wave (PWM) with >1ms period and >0.2ms pulse
• Momentary (<0.5s) push on D7 switch cycles through available sampling speeds
• Long >0.5s push on D7 freezes display.

Entire project

UNO R3 and Teensy 3.1 (with upside-down display mode).

Parts

• Arduino board:
  • Arduino UNO R3, Arduino Pro Mini, Arduino Pro Trinket or Other Arduino Atmega328 board, or
  • Teensy 3 (less expensive and more powerful)
• 0.96" OLED display with SSD1306 and I2C mode (that's what I tried. SPI mode is also supported by the Adafruit library but wiring is different). Many stores sell these and in different colors.
• Arduino IDE
• type B USB cable, few jumper wires

Libraries

Either use Sketch -> Import Library or make a libraries folder and drop them in there.

• Adafruit_SSD1306 from https://github.com/adafruit/Adafruit_SSD1306
  • Must edit Adafruit_SSD1306.h to pick the set display type to SSD1306_128_64
• Adafruit_GFX from https://github.com/adafruit/Adafruit-GFX-Library