This project has been successfully founded on KickStarter!

Check out also the MickMake and EEVblog videos!

What is it?

The I2C Encoder is a tiny board that you can read a mechanical rotary encoder on the I2C bus. The I2C Encoder V2 supports various type of rotary encoder with one footprint:

• Standard mechanical encoder
• Illuminated RGB encoder
• Clickable rotary encoder
• With and without dent

There are also 3 configurable GPIOs that are organized with the same footprint of RGB LED. You can use them as PWM, I/O or ADC. Last but not least, it has also 256bytes of EEPROM.

There is also the little brother I2C Encoder Mini

Features

• I2C bus working up to 400kHz
• Possibility to customize the I2C address by soldering the 7 SMD jumpers
• It supports the standard rotary encoder and the RGB encoder
• Support gamma correction for the LEDs
• Support automatic fading
• Open-drain Interrupt output pin, so no need to continuously poll the devices
• With the castellated holes it is possible to connect several boards on the 4 sides
• 5 pin header 2.54mm pitch on the left and right side, also the JST-XH fit
• 3 General Purpose pins. (GP pins)
• 256byte of internal EEPROM divided into 2 banks of 128 byte
• Voltage range is 3.3V to 5V
• Maximum A/B signal frequency: 100Hz (Tested)
• Dimension of 25x25mm or 0.98x0.98in
• Open source firmware

Details

This new version is powered by the PIC16F18345. Respect to the MCU on the first version, it has more GPIO and the EEPROM memory. The new design of the board support both the standard encoders and the illuminated RGB encoders. Moreover, there are the castellated holes on all the 4 sides of the board, in this way will be possible to connect multiple boards by soldering them like a matrix.

The I2C Encoder V2.1 have also pre-soldered the pull-up resistor on the I2C bus. The can be enabled by soldering a jumper.

The I2C Encoder V2.1 can be used in two different scenarios:

• With a standard rotary encoder. Plus you can add an external RGB LED, or you can use the 3 GPIOs
• With an illuminated RGB rotary encoder. Plus you can use 2 GPIOs.

Reading the encoder is a very easy task.

There are 4 registers:

• CVAL: Current value of the Encoder. This value changes every time the encoder rotates.
• CMAX: Maximum value that CVAL can reach
• CMIN: Minimum value that CVAL can reach
• ISTEP: How much the CVAL has to increment at each and every encoder step.

These 4 registers can be 32bit signed INT, or as float numbers IEEE 754.

LEDs

The I2C Encoder has also the possibility to control LEDs. The LEDs are controlled by an 10bit PWM.

There is also the possibility to enable a gamma correction for the LED color.

GPIOs

There are also 3 configurable GPIOs organized with the same footprint of an RGB LED. They are called GP1, GP2, and GP3. But in case you are using the RGB encoder, the configurable GPIOs are only 2: GP1 and GP2.

Possible configuration:

• PWM: In this way, you can add an RGB LED
• Analog: The pins are connected to the internal ADC of the PIC. In this way, you can add sensors or potentiometer according to your project needs
• Output: You can use the pins as standard digital output
• Input: You can use the pins as standard digital input. Plus you can configure also the interrupt on the edges

Documentation:

• Project
• Arduino Library

Shipping is done every Monday morning, please place the order before!

Package includes:

1 I2C Encoder V2.1 board fully programmed (without encoder, connector and LED)

However, there are some accessory taht you can add into your order according to your preference. The accerssory are not soldered, you have solder by your self.

Encoders

There are 4 types of standard encoders. All have 20 pulses for rotations and the push button:

• EC11 with handle 20mm long and 6mm diameter.
• EC11 with handle 15mm long and 6mm diameter.
• Bourns PEC11L-4115F-S0020 with handle 15mm long and 6mm diameter.
• Bourns PEC11L-4120F-S0020 with handle 20mm long and 6mm diameter.
• Bourns PEC11L-4020F-S0020 no dent with handle 20mm long and 6mm diameter.

There are also an illuminated RGB Encoder with the following characteristics:

• 12mm transparent knurled shaft
• 24 pulse
• 0.5mm switch travel

Knobs

There are 2 type of knobs only for the RGB Encoder, not for the others encoder:

Complete transparent knob:

• Skirt diameter: 20mm
• Upper part diameter: 13mm
• Total height: 19mm

Black knob with illuminated ring:

• Skirt diameter: 25mm
• Upper part diameter: 19mm
• Total height: 15mm

If you connect the I2C encoder V2 with the castellated holes, this knob doesn't fit! Because the knob is to much big!

Connectors

There are also 2 type of connector:

• Male and female 5 pin header
• JST connector with 30cm wire

Example of mounting with JST connector with 30cm wire:

Example of male and female 5 pin header

## RGB LED Ring

This is a 40mm LED ring with 48 RGB LED working on the I2C bus. It perfectly fit on the RGB Encoder and the normal encoder.

Project from Richie with 24 I2C Encoder V2 connected to Teesy 3.6

Difference between the V2 and the V2.1:

This is an upgraded version of our previous project I2C Encoder V2

Hardware changes:

• Added the jumper SJ8 for enable the pull-up resistor in the I2C bus.
• R1 and R2 are already soldered on the board with a 0402 footprint.
• Changed the value of R3 and R4 with 42.2
• Changed the value of R5 with 107

Firmware changes:

• Added the gamma correction feature.
• Added the unique code and the version registers.
• Added the possibility to enable/disable the I2C clock stretch.
• Added and extra delay after the detection of the double-push.
• Added the possibility to count absolute or relative steps
• Decreased of the 33% the power consumption.
• Changed the default value of ISTEP from 1 to 0.

Comparison between the I2C Encoder V2.1 and I2C Encoder Mini

Similar project:

• I2C Encoder Mini
• I2C NavKey