📌 Used parts: Arduino Nano: https://www.ebay.com/itm/MINI-USB-Nano-V3-0-ATmega328P-CH340G-5V-16M-Micro-controller-Board-Arduino/263028181552?hash=item3d3db38a30:m:mEdYzNzkjui_b1LT1jFlvUA 128 x 32’’ I2C OLED Display: https://www.ebay.com/itm/1pcs-0-91-128x32-IIC-I2C-OLED-LCD-Display-DIY-Module-DC3-3V-5V-For-PIC-Arduino/183447406048?hash=item2ab65145e0%3Am%3AmMxose4lr_WvUOaZBpEgB-Q&LH_BIN=1 Tactile Push Button (6x6x7mm): https://www.ebay.com/itm/2-Pin-Momentary-Tactile-Tact-Push-Button-Switch-Black-6x6x4-3mm-7mm-Miniature/183251999404?hash=item2aaaab9aac:m:m40riuiMesI0w5neIvrkrPQ Battery connector: https://www.ebay.com/itm/10-Pcs-Snap-9V-9-Volt-Battery-Clip-Connector-I-Type-Black-w-Cable-Black/122813228347?hash=item1c983d253b%3Ag%3AZfUAAOSwDrNZS16w&LH_BIN=1 Laser emitter: https://www.ebay.com/itm/650nm-6mm-5V-5mW-mini-Laser-Dot-Diode-Module-Copper-X6B2-SAL-Dot-Red-Head-K-K2X9/264416958362?hash=item3d907a979a:g:sjAAAOSwRn5dQ0Sx Laser sensor: https://www.ebay.com/itm/Laser-Sensor-Module-non-modulator-Tube-Laser-Receiver-Module-DIY-For-arduino-WF/372880764757?hash=item56d16cef55:g:DJUAAOSwmxVdnvDY M2x6mm Screws: https://www.ebay.com/itm/50PCS-M2X6mm-Screws-Stainless-Steel-Round-Head-Plain-End-Metric-Machine/401255438898?hash=item5d6cb01a32:g:MWwAAOSwopRYb-h6 📌 Other: 3D File: https://www.thingiverse.com/Elite_Worm/about Code: https://github.com/EliteWorm/Tachometer/blob/master/Laser_Tachometer_V1_0_0.ino Third party used libraries: https://github.com/adafruit/Adafruit_SSD1306 https://github.com/adafruit/Adafruit-GFX-Library Electronic connections: 128 x 32’’ I2C OLED Display to Arduino Nano as follows: GND to GND VCC to 5V SCK to A5 SDA to A4 9V Battery to Arduino Nano as follows: Negative (black) to GND Positive (red) to Push Button Pin 1 and Push Button Pin 2 to VIN Laser Diode to Laser Sensor Module as follows: Positive (red) to VCC Negative (blue) to GND Laser Sensor Module to Arduino Nano as follows: VCC to 5V GND to GND OUT to D2