# Pro Trinket Tachometer ## Overview Cutting tools and drill bits work best when run at the correct speed for the material being cut.  Too fast or too slow can result in inefficient cutting, rough surfaces, heat buildup, premature dulling and/or tool breakage.  References such as [Machinery's Handbook](https://www.amazon.com/s/?ie=UTF8&keywords=machinery%27s+handbook&tag=googhydr-20&index=aps&hvadid=228967076633&hvpos=1t1&hvnetw=g&hvrand=14666692617892107412&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9002062&hvtargid=kwd-324143135994&ref=pd_sl_9bh0gjicgc_e_p38) have extensive tables of "Feeds and Speeds" for various types of cutting tools and materials. But how do you know how fast your machine is running?  Some machines have a variable speed control, but no precise feedback on the actual speed.  The Pro Trinket Tachometer attaches to your machine to sense and display the actual rotation rate. ![](https://cdn-learn.adafruit.com/assets/assets/000/043/685/medium800/sensors_234A2196.jpg?1499619783) ### Materials Required: - [5v Pro Trinket](https://www.adafruit.com/product/2000) - [7-Segment Display with i2c backpack.](https://www.adafruit.com/product/881) - [Reflective IR sensor with 470 ohm resistor](https://www.adafruit.com/product/2349) - Wire - Soldering Supplies ### Recommended or Optional Materials (as needed for installation on your machine) - [Power Supply](https://www.adafruit.com/product/63) - [Barrel Jack](https://www.adafruit.com/product/610) - Project box or other enclosure - Black Tape - White Paint   - [Next Page](https://learn.adafruit.com/pro-trinket-tachometer/circuit-design.md) ## Featured Products ### Adafruit Pro Trinket - 5V 16MHz [Adafruit Pro Trinket - 5V 16MHz](https://www.adafruit.com/product/2000) **Deprecation Warning: The Pro Trinket bit-bang USB technique it uses doesn't work as well as it did in 2014, many modern computers won't work well. So while we still carry the Pro Trinket so that people can maintain some older projets, we no longer recommend it.** Please... In Stock [Buy Now](https://www.adafruit.com/product/2000) [Related Guides to the Product](https://learn.adafruit.com/products/2000/guides) ### Reflective Infrared IR Optical Sensor with 470 and 10K Resistors [Reflective Infrared IR Optical Sensor with 470 and 10K Resistors](https://www.adafruit.com/product/2349) This **Reflective IR Sensor** is a simple plastic casing with two elements - an IR LED and an IR phototransistor. You can control the IR LED and turn it on to bounce IR off objects to determine their reflectivity. White & light colored stuff will bounce the light, so  you... In Stock [Buy Now](https://www.adafruit.com/product/2349) [Related Guides to the Product](https://learn.adafruit.com/products/2349/guides) ### Adafruit 0.56" 4-Digit 7-Segment Display w/ I2C Backpack - Blue [Adafruit 0.56" 4-Digit 7-Segment Display w/ I2C Backpack - Blue](https://www.adafruit.com/product/881) What's better than a single LED? Lots of LEDs! A fun way to make a small display is to use an [8x8 matrix](https://www.adafruit.com/category/37_88) or a [4-digit 7-segment display](https://www.adafruit.com/category/37_103). Matrices like these are... In Stock [Buy Now](https://www.adafruit.com/product/881) [Related Guides to the Product](https://learn.adafruit.com/products/881/guides) ### Panel Mount 2.1mm DC barrel jack [Panel Mount 2.1mm DC barrel jack](https://www.adafruit.com/product/610) This power jack is designed to easily attach to a panel up to 8mm thick (0.315" or 5/16") and fit 2.1mm power plugs snugly and securely. Perfect for adding a power connector to your project enclosure. We like this jack in particular for its long body (so you can use it on thicker... In Stock [Buy Now](https://www.adafruit.com/product/610) [Related Guides to the Product](https://learn.adafruit.com/products/610/guides) ### 9 VDC 1000mA regulated switching power adapter - UL listed [9 VDC 1000mA regulated switching power adapter - UL listed](https://www.adafruit.com/product/63) This is a really nice power supply. It's a switching DC supply so it's small and light and efficient. It is thin so it fits in power strips without blocking other outlets. The output is regulated so you'll get a steady 9V up to 1000mA (1 Amp) of current draw. 5.5mm/2.1mm barrel... In Stock [Buy Now](https://www.adafruit.com/product/63) [Related Guides to the Product](https://learn.adafruit.com/products/63/guides) ## Related Guides - [Adafruit LED Backpacks](https://learn.adafruit.com/adafruit-led-backpack.md) - [Pro Trinket as a USB HID Mouse](https://learn.adafruit.com/pro-trinket-usb-hid-mouse.md) - [Talking d20 20-Sided Gaming Die](https://learn.adafruit.com/talking-d20-20-sided-gaming-die.md) - [Steampunk Cameo Necklace with OLED Display](https://learn.adafruit.com/steampunk-cameo-necklace.md) - [LED Campfire](https://learn.adafruit.com/led-campfire.md) - [Adafruit Pro Trinket LiPoly/LiIon Backpack](https://learn.adafruit.com/adafruit-pro-trinket-lipoly-slash-liion-backpack.md) - [No-Code Snowfall Tracker with WipperSnapper and Adafruit IO](https://learn.adafruit.com/no-code-snow-tracker-with-wippersnapper-and-adafruit-io.md) - [Mindfulness Clock OF DOOM](https://learn.adafruit.com/mindfulness-clock-of-doom.md) - [Your Pulse Displayed with NeoPixels](https://learn.adafruit.com/pulse-sensor-displayed-with-neopixels.md) - [Arduino GPS Clock](https://learn.adafruit.com/arduino-clock.md) - [Ray Gun Blaster](https://learn.adafruit.com/ray-gun-blaster.md) - [Wizzy: A Needle Felted Cat](https://learn.adafruit.com/wizzy-a-needle-felted-cat.md) - [Color Balancing Video Camera Light feat. DotStars](https://learn.adafruit.com/color-balancing-light-box-with-dotstar-cool-warm-white-leds.md) - [Fiddy - the FTDI Clip](https://learn.adafruit.com/fiddy-ftdi-pogo-pin-clip.md) - [Introducing the iTapStick: Video Game USB Mouse Stick for Wii Nunchuk Controllers](https://learn.adafruit.com/nunchuket-kung-fu-pc-video-game-fighting-stick.md) - [CircuitPython Hardware: LED Backpacks & FeatherWings](https://learn.adafruit.com/micropython-hardware-led-backpacks-and-featherwings.md)