Add IOIO article

_build/pages/articles.markdown

@@ -28,6 +28,7 @@
 - [Clipboard: Copy and paste](/pages/plugins_clipboard.html)
 - [GIFenc: create animated GIFs](/pages/plugins_gifenc.html)
 - [PiGPIO: Use the GPIO pins of a Raspberry Pi](/pages/plugins_pigpio.html)
+- [IOIO: Drive hardware from Android](/pages/plugins_ioio.html)
 
 ## Units
 

_build/pages/plugins_ioio.markdown

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+# IOIO plugin
+
+The IOIO is a board that provides a host machine the capability
+of interfacing with external hardware over a variety of commonly
+used protocols. The original IOIO board has been specifically
+designed to work with Android devices. The newer IOIO-OTG
+("on the go") boards work with both Android devices and PC's.
+The IOIO board can be connected to its host over
+USB or Bluetooth, and provides a high-level Java API on the host
+side for using its I/O functions as if they were an integral
+part of the client. ([IOIO website](https://github.com/ytai/ioio/wiki))
+
+## How to learn coding for IOIO
+
+For most of the protocols you can find a SmallBASIC example at
+[Github](https://github.com/smallbasic/smallbasic.plugins/tree/master/ioio/samples).
+Below is a list with all examples and an image how to wire.
+If you are new to IOIO it is best to start with the first example.
+
+A simple SmallBASIC cheatsheet is available at
+[Github](https://github.com/smallbasic/smallbasic.plugins/tree/master/ioio).
+
+For further information please visit the [IOIO website](https://github.com/ytai/ioio/wiki).
+
+## How to setup SmallBASIC to use the IOIO plugin
+
+Getting IOIO running on a PC (Linux) requires to build the plugin from source. This is not part of this document.
+
+Using IOIO on Android is quite easy:
+
+- Launch SmallBASIC and then click on "Setup".
+- On the second screen, click to "Load extension modules".
+- Restart SmallBASIC and then click "About". You should see: "Extension modules: enabled".
+- If you have enabled Android developer options, make sure USB debugging is disabled.
+- On your IOIO-OTG board, connect a power source to the VIN + GND.
+  - IOIO should be powered by an external DC voltage source between 5V-15V.
+  - 9V battery works well.
+  - But it is better to connect a 5V power supply.
+  - Instead of VIN + GND you can use the 2-pin JST Female Power Jack
+- Connect a USB cable between your mobile or tablet and the board (use the included red adaptor plus another cable).
+- You should see "IOIO Standard application - no installed apps".
+- Launch "led.bas"
+- You should see a prompt requesting permission for SmallBASIC to access the board. Click okay.
+- You should then see a toast message: IOIO board access permitted.
+- For this initial setup "led.bas" has now timed out. You should be able to re-launch "led.bas" for successful operation.
+
+You have to connect power to the board, because it will act as an host and it will charge your Android device.
+
+## Examples
+
+### Digital output
+
+#### LED
+
+[led.bas](https://github.com/smallbasic/smallbasic.plugins/blob/master/ioio/samples/led.bas)
+
+![](/images/ioio/ioioboard.png)
+
+#### PWM
+
+[pwm.bas](https://github.com/smallbasic/smallbasic.plugins/blob/master/ioio/samples/pwm.bas)
+
+![](/images/ioio/PWM.png)
+
+#### HD44780 text display
+
+[hd44780.bas](https://github.com/smallbasic/smallbasic.plugins/blob/master/ioio/samples/hd44780.bas)
+
+![](/images/ioio/HD44780.png)
+
+### Digital input
+
+[button.bas](https://github.com/smallbasic/smallbasic.plugins/blob/master/ioio/samples/button.bas)
+
+![](/images/ioio/button.png)
+
+### Analog input
+
+[slider-pot.bas](https://github.com/smallbasic/smallbasic.plugins/blob/master/ioio/samples/slider-pot.bas)
+
+![](/images/ioio/SliderPot.png)
+
+### I2C
+
+#### BH1750 - Ambient light sensor
+
+[bh1750.bas](https://github.com/smallbasic/smallbasic.plugins/blob/master/ioio/samples/bh1750.bas)
+
+![](/images/ioio/BH1750.png)
+
+#### BME280 - Temperature and humidity sensor
+
+[bme280.bas](https://github.com/smallbasic/smallbasic.plugins/blob/master/ioio/samples/bme280.bas)
+
+![](/images/ioio/BME280.png)
+
+#### MPU6050 - Accelerometer, gyroscope and temperature sensor
+
+[mpu6050.bas](https://github.com/smallbasic/smallbasic.plugins/blob/master/ioio/samples/mpu6050.bas)
+
+![](/images/ioio/MPU6050.png)
+
+#### VEML6030 - Ambient-light sensor
+
+[veml6030.bas](https://github.com/smallbasic/smallbasic.plugins/blob/master/ioio/samples/veml6030.bas)
+
+![](/images/ioio/VEML6030.png)
+
+#### SSD1306 - OLED with 128x64 monochrome pixels
+
+[ssd1306.bas](https://github.com/smallbasic/smallbasic.plugins/blob/master/ioio/samples/ssd1306.bas)
+
+![](/images/ioio/SSD1306.png)
+
+### SPI
+
+#### 1088AS - 8x8 dot matrix module
+
+[duino-1088as.bas](https://github.com/smallbasic/smallbasic.plugins/blob/master/ioio/samples/duino-1088as.bas)
+
+![](/images/ioio/duino1088as.png)
+
+#### ST7789 - TFT controller
+
+[st7789.bas](https://github.com/smallbasic/smallbasic.plugins/blob/master/ioio/samples/st7789.bas)
+
+SPI is too slow on IOIO to drive a TFT display.
+
+#### ST7735 - TFT controller
+
+[st7735.bas](https://github.com/smallbasic/smallbasic.plugins/blob/master/ioio/samples/st7735s.bas)
+
+SPI is too slow on IOIO to drive a TFT display.