# Introducing Adafruit Trellis ## Overview ![](https://cdn-learn.adafruit.com/assets/assets/000/012/733/medium800/adafruit_products_1616_LRG.jpg?1386359574) ![](https://cdn-learn.adafruit.com/assets/assets/000/012/752/medium800/adafruit_products_1616finger8x8_LRG.jpg?1386361285) Trellis is an open source backlight keypad driver system. It is easy to use, works with any 3mm LEDs and eight tiles can be tiled together on a shared I2C bus. ![](https://cdn-learn.adafruit.com/assets/assets/000/012/730/medium800/adafruit_products_1616top_LRG.jpg?1386359520) The Trellis PCB is specially made to match the Adafruit 4x4 elastomer keypad. Each Trellis PCB has 4x4 pads and 4x4 matching spots for 3mm LEDs. The circuitry on-board handles the background key-presses and LED lighting for the 4x4 tile. However, it does not have any microcontroller or other 'brains' - an Arduino (or similar microcontroller) is required to control the Trellis to read the keypress data and let it know when to light up LEDs as desired. ![](https://cdn-learn.adafruit.com/assets/assets/000/012/732/medium800/adafruit_products_1616bottom_LRG.jpg?1386359558) Each tile has an I2C-controlled LED sequencer and keypad reader already on it. The chip can control all 16 LEDs individually, turning them on or off. It cannot do grayscale or dimming. The same chip also reads any keypresses made with the rubber keypad. The connections are 'diode multiplexed' so you do not have to worry about "ghosting" when pressing multiple keys, each key is uniquely addressed. ![](https://cdn-learn.adafruit.com/assets/assets/000/012/750/medium800/adafruit_products_1616casual8x8_LRG.jpg?1386361254) The tiles have 3 address jumpers. You can tile up to 8 PCBs together (for a total of 4x32 or 16x8=128 buttons/leds) on a single I2C bus, as long as each one has a unique address. All the tiles connect by the edges with solder, and share the same power, ground, interrupt, and i2c clock/data pins. So, you can easily set up to 128 LEDs and read up to 128 buttons using only 2 I2C wires! The tiles can be arranged in any configuration they want as long as each tile is connected to another with the 5 edge-fingers. ![](https://cdn-learn.adafruit.com/assets/assets/000/012/751/medium800/adafruit_products_1616bottom8x8_LRG.jpg?1386361264) Each LED is multiplexed with a constant-current driver, so you can mix and match any colors you like. You don't need it to be all blue, all red, etc. Mix it up! Any 3mm LED can be used, although we find that diffused LEDs with 250mcd+ brightness look best. - [Next Page](https://learn.adafruit.com/adafruit-trellis-diy-open-source-led-keypad/adding-leds.md) ## Featured Products ### Adafruit Trellis Monochrome Driver PCB for 4x4 Keypad & 3mm LEDs [Adafruit Trellis Monochrome Driver PCB for 4x4 Keypad & 3mm LEDs](https://www.adafruit.com/product/1616) **This item is just for the Trellis driver PCB assembly: LEDs and buttons not included.** Trellis is an open source backlight keypad driver system. It is easy to use, works with any 3mm LEDs and eight tiles can be tiled together on a shared I2C bus. This PCB is... Out of Stock [Buy Now](https://www.adafruit.com/product/1616) [Related Guides to the Product](https://learn.adafruit.com/products/1616/guides) ### Silicone Elastomer 4x4 Button Keypad - for 3mm LEDs [Silicone Elastomer 4x4 Button Keypad - for 3mm LEDs](https://www.adafruit.com/product/1611) So squishy! These silicone elastomer keypads are just waiting for your fingers to press them. Go ahead, squish all you like! (They're durable and easy to clean, just wipe with mild soap and water) These are just like the light up rubber buttons you find on stuff like appliances and tools,... In Stock [Buy Now](https://www.adafruit.com/product/1611) [Related Guides to the Product](https://learn.adafruit.com/products/1611/guides) ### Adafruit METRO 328 Fully Assembled - Arduino IDE compatible [Adafruit METRO 328 Fully Assembled - Arduino IDE compatible](https://www.adafruit.com/product/50) We sure love the ATmega328 here at Adafruit, and we use them _a lot_ for our own projects. The processor has plenty of GPIO, Analog inputs, hardware UART SPI and I2C, timers and PWM galore - just enough for most simple projects. When we need to go small, we use a Out of Stock [Buy Now](https://www.adafruit.com/product/50) [Related Guides to the Product](https://learn.adafruit.com/products/50/guides) ### Diffused Blue 3mm LED (25 pack) [Diffused Blue 3mm LED (25 pack)](https://www.adafruit.com/product/780) Need some indicators? We are big fans of these diffused blue LEDs, as featured in the LoL shield. They are really bright so they can be seen in daytime, and from any angle. They go easily into a breadboard and will add that extra zing to your project. - Pack of 25 diffused blue... In Stock [Buy Now](https://www.adafruit.com/product/780) [Related Guides to the Product](https://learn.adafruit.com/products/780/guides) ### Diffused White 3mm LED (25 pack) [Diffused White 3mm LED (25 pack)](https://www.adafruit.com/product/778) Need some indicators? We are big fans of these diffused white LEDs, as featured in the LoL shield. They are really bright so they can be seen in daytime, and from any angle. They go easily into a breadboard and will add that extra zing to your project. - Pack of 25 diffused white... In Stock [Buy Now](https://www.adafruit.com/product/778) [Related Guides to the Product](https://learn.adafruit.com/products/778/guides) ### Diffused Red 3mm LED (25 pack) [Diffused Red 3mm LED (25 pack)](https://www.adafruit.com/product/777) Need some indicators? We are big fans of these diffused red LEDs, as featured in the LoL shield. They are fairly bright so they can be seen in daytime, and from any angle. They go easily into a breadboard and will add that extra zing to your project. - Pack of 25 diffused red... In Stock [Buy Now](https://www.adafruit.com/product/777) [Related Guides to the Product](https://learn.adafruit.com/products/777/guides) ### Diffused Green 3mm LED (25 pack) [Diffused Green 3mm LED (25 pack)](https://www.adafruit.com/product/779) Need some indicators? We are big fans of these diffused green LEDs, as featured in the LoL shield. They are fairly bright so they can be seen in daytime, and from any angle. They go easily into a breadboard and will add that extra zing to your project. - Pack of 25 diffused green... In Stock [Buy Now](https://www.adafruit.com/product/779) [Related Guides to the Product](https://learn.adafruit.com/products/779/guides) ## Related Guides - [Smart Cocktail Shaker](https://learn.adafruit.com/smart-cocktail-shaker.md) - [Let’s Put LEDs in Things!](https://learn.adafruit.com/lets-put-leds-in-things.md) - [AdaBox 010](https://learn.adafruit.com/adabox010.md) - [1,500 NeoPixel LED Curtain with Raspberry Pi and Fadecandy](https://learn.adafruit.com/1500-neopixel-led-curtain-with-raspberry-pi-fadecandy.md) - [Trellis Feather DSP-G1 Synthesizer](https://learn.adafruit.com/feather-trellis-dsp-g1-synthesizer.md) - [Mini Thermal Receipt Printers](https://learn.adafruit.com/mini-thermal-receipt-printer.md) - [Low Power WiFi Datalogger](https://learn.adafruit.com/low-power-wifi-datalogging.md) - [Adafruit Motor Shield](https://learn.adafruit.com/adafruit-motor-shield.md) - [Arduino Tips, Tricks, and Techniques](https://learn.adafruit.com/arduino-tips-tricks-and-techniques.md) - [OLED TRON Clock](https://learn.adafruit.com/oled-tron-clock.md) - [Ladyada's Learn Arduino - Lesson #1](https://learn.adafruit.com/ladyadas-learn-arduino-lesson-number-1.md) - [Remote Effects Trigger Box](https://learn.adafruit.com/remote-effects-trigger.md) - [Adafruit VS1053 MP3/AAC/Ogg/MIDI/WAV Codec Breakout Tutorial](https://learn.adafruit.com/adafruit-vs1053-mp3-aac-ogg-midi-wav-play-and-record-codec-tutorial.md) - [Neotrellis M4 Live Launcher](https://learn.adafruit.com/neotrellis-live-launcher.md) - [NeoTrellis MIDI Feedback Controller](https://learn.adafruit.com/neotrellis-midi-feedback-controller.md)