This document discusses using mruby for rapid IoT prototyping. It introduces mruby and how it can help address bottlenecks in prototyping like slow firmware transfer speeds. It describes the ESP32 microcontroller and how the mruby-esp32 project ports mruby to run on the ESP32, providing examples of using mruby with ESP32 peripherals like GPIO and I2C. It also mentions the mruby 1.4.0 release and the mruby/c implementation for very small memory devices.

1. Rapid IoT prototyping with mruby
IoTLT MORIOKA #2
@pandax381

2. Hello!
‣YAMAMOTO Masaya
‣ @pandax381
‣Work at KLab Inc.
‣ K-Laboratory (R&D dept.)
‣ C programmer
‣ I can network programming a little
‣ OSS Contribution

3. Now I’m into Hobby Electronics
https://www.youtube.com/watch?v=DkHOJYTbYVk

4. IoT prototyping

5. IoT - Internet of Things
+ +
DeviceSensor
(and Motor)
Network

6. IoT - Internet of Things

7. Cycle of prototyping
Making
CodingTesting

8. ‣Poor system resource
‣ Processor <= 100MHz
‣ Memory <= 100KB
‣ Strorage <= 1MB
‣Development language
‣ C or similar languages
Bottleneck of prototyping

9. Bottleneck of prototyping
‣Transferring Flash Image
‣ UART (Serial Port) rate 115,200 bps
1MB => 72.8sec
Firmware

11. ESP32

12. ESP32 microcontroller
‣Low-cost and Hi-performance SoC
‣ Wi-Fi & Bluetooth support
‣TELEC Certified !!
‣ Xtensa LX6 Dual-core 240MHz
‣ 520KB SRAM
‣ Rich Peripheral interfaces
‣ I2C, I2S, SPI, SDIO, UART, ADC, DAC
IR, PWM, Temp sensor, Touch sensor …

14. Development environment of ESP32
‣ESP-IDF (Espressif IoT Development Framework)
‣ Official development environment
‣ FreeRTOS + newlib
‣ Provide Native C API and library
‣Arduino core for the ESP32
‣ Yet another official development environment
‣ Provide Arduino compatible API and library (similar C)
‣ Developable with Arduino IDE

15. meets

16. mruby-esp32
‣Port mruby to ESP32
‣ https://github.com/mruby-esp32

17. mruby-esp32
‣mruby-esp32
‣ mruby standalone application template for ESP32
‣ Original code author is Mr. Carson McDonald.
‣mruby-esp32-app-mirb
‣ Running mirb (Embeddable Interactive Ruby Shell)
‣ Use mruby-esp32

18. Demo
https://www.youtube.com/watch?v=XIvaMQ7gUAo

19. mruby-esp32’s mrbgems
‣mruby-esp32-system
‣ System specific library (sleep, SDK version, etc…)
‣mruby-esp32-wifi
‣ Provide Wi-Fi connection setting
‣mruby-io / mruby-socket
‣ Ported to the ESP32 (Support lwIP)
‣mruby-esp32-gpio / mruby-esp32-i2c
‣ Provide GPIO and I2C access (LED, LCD, Sensors…)

20. Demo
https://www.youtube.com/
watch?v=M_mGSt0bB-4
include ESP32
i2c = I2C.new(I2C::PORT0).init(I2C::MASTER)
p i2c.scan
lcd = ST7032.new(i2c)
until lcd.ready?
System.delay(1000)
end
lcd.init
lcd.print("Hello, world!")
System.delay(3000)
(0..63).each {|c|
lcd.contrast(c)
lcd.print("c=#{c}")
System.delay(100)
}
lcd.contrast(32)
lcd.clear
i2c.deinit

21. Case Example
http://mruby.sh/201707150753.html

22. Case Example
http://2017.rubyworld-conf.org/ja/program/

23. mruby 1.4.0 was released at January 16, 2018

24. mruby 1.4.0
‣MRB_WITHOUT_FLOAT (Build option)
‣ Remove floating point numbers from mruby
‣ It can running without FPU (and soft-float)
‣ It also easy works in Kernel-space and BareMetal

25. for more tiny devices…

26. mruby/c
‣mruby/c is an another implementation of mruby.
‣ Small memory consumption (<40KB)
‣ Limited class libraries
‣ Small size rather than execution speed
https://github.com/mrubyc/mrubyc

27. Let's Happy Prototyping with mruby!