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#include <SoftwareSerial.h>
SoftwareSerial BT(10, 11);
// creates a "virtual" serial port/UART
// connect BT module TX to D10
// connect BT module RX to D11
// connect BT Vcc to 5V, GND to GND
void setup()
{
// set digital pin to control as an output
/* HC-SR04 Sensor
https://www.dealextreme.com/p/hc-sr04-ultrasonic-sensor-distance-measuring-module-133696
This sketch reads a HC-SR04 ultrasonic rangefinder and returns the
distance to the closest object in range. To do this, it sends a pulse
to the sensor to initiate a reading, then listens for a pulse
to return. The length of the returning pulse is proportional to
the distance of the object from the sensor.
The circuit:
#define PIN_SCE 7
#define PIN_RESET 6
#define PIN_DC 5
#define PIN_SDIN 4
#define PIN_SCLK 3
#define LCD_C LOW
#define LCD_D HIGH
@romaHerman
romaHerman / States-v3.md
Created August 17, 2016 07:42 — forked from andymatuschak/States-v3.md
A composable pattern for pure state machines with effects (draft v3)

A composable pattern for pure state machines with effects

State machines are everywhere in interactive systems, but they're rarely defined clearly and explicitly. Given some big blob of code including implicit state machines, which transitions are possible and under what conditions? What effects take place on what transitions?

There are existing design patterns for state machines, but all the patterns I've seen complect side effects with the structure of the state machine itself. Instances of these patterns are difficult to test without mocking, and they end up with more dependencies. Worse, the classic patterns compose poorly: hierarchical state machines are typically not straightforward extensions. The functional programming world has solutions, but they don't transpose neatly enough to be broadly usable in mainstream languages.

Here I present a composable pattern for pure state machiness with effects,

//: Playground - noun: a place where people can play
import UIKit
let formatter = DateFormatter()
formatter.dateFormat = "yyyy MM dd"
let date = formatter.date(from: "2017 03 31")