The module features a controller chip handling I2C communications and an adjustable potentiometer for changing the intensity of the LED backlight. LCDs incorporate a small add-on circuit (backpack) mounted on the back of the LCD module.

The character LCD is ideal for displaying text and numbers and special characters. We offer both a 2 x 16 LCD along with the larger 4 x 20 LCD. Using an I2C interface, only two connections for an LCD character display are possible with stunning professional results. Adding an external display would typically require several of the limited I/O pins. The ability to interface to external devices readily is very enticing, although the Arduino has a limited number of input/output options. The Arduino family of devices is features rich and offers many capabilities. Dayton Hamvention Previous Years Vendors.LED Series Dropping Resistor Calculator.

LED Specifications and Application Notes.LED Specifications and Application Notes Expand.LED Spotlight Junior – 18-LED Spotlight Board.NodeMCU IoT Experimenter Prototype Board.Easily Configure Arduino IDE for NodeMCU.I2C LCD on Arduino – Stunningly Easily Setup.When I let D4 “float”, the LED turned on. When I grounded D4 on the Spark, the LED went out. On the arduino side, I used this code: #include īecause I used a 3.3V Arduino pro mini, I put an LED to ground via a resistor on digital pin 3. Also, note I removed the boolean on the last_state and made it an INT since that’s what digitalRead returns. The original code was looking for a change in the button and would xmit that change to the slave.

The button “bebounce” that BDub suggested was great but that is not what was needed. First, as per timb, I made the Spark the master with this code: #include 'application.h' Here’s the code I’m running on the Core: #define LED D7Īny help would be greatly appreciated, thanks in advance.Įverything is working! However, there are a couple of things I had to fix. I have the code working between 2 Unos but not to the Core. The intension was to use this sketch to confirm I have the I2C communication working before using it in “real” applications. I have connections between D0 -> A4 and D1 -> A5, both with 4k7 pull-up resistors, GND -> GND and +5 -> Vin.įor now I’m just trying to press a switch on one board and have the on-board LED light on the other. I’m having some issues communicating between a Spark Core and an Arduino Uno via I2C.

Arduino wire library problem