Latest revision as of 11:55, 5 February 2019

Michael's Home Instrumentation

New porch doors have required me to rethink my doorbell!
We can't hear people knocking on the door
The people at the door don't know if the old doorbell actually rang
The old wireless doorbell often didn't ring because the batteries were flat!
The wireless doorbell didn't require drilling holes in the doorframe - this is a plus
the 12V battery in the wireless doorbell pushbutton was expensive!

I want to do something simple with the old wireless doorbell and start to develop an extensible home automation/instrumentation project. I have a Nanode and a number of Xinos which I intend to connect on a 4-wire bus around the house.

The old doorbell

Push-button:

PCB labelled "RL-09 04.04.23"
Battery 12V A23S "Replaces: 23A, MS21/MN21" A23 on WP cheap 10x pack
IC1: LP801/V8

Chime unit:

PCB labelled "RL-09B 04.02.27"
Batteries 4.5V, 3xAA
IC2: LP816A

http://www.alldatasheet.com/view.jsp?Searchword=HCF4069UBE

The Nanode - Xino 4-wire Bus

Using a Nanode at my internet gateway router and communicating with and powering multiple slave Xinos on a 4-wire bus...

http://wiki.hackspace.org.uk/wiki/Project:Nanode/Applications#Using_the_Local_Serial_Bus

http://sustburbia.blogspot.com/2010/08/wired-network-for-arduinos.html

Read nanode MAC address: -

https://gist.github.com/1020951#file_nanode_mac.pde

 MAC Address Read Test
 MAC address is 00:04:A3:03:DD:C7

The soil moisture tester

Do these plants need watering?

http://www.instructables.com/id/Garduino-Gardening-Arduino/

Temperature

I have a bag of surplus 47k thermistors (about 500) and I intend to build a number of circuits to measure temperature starting with the very simplest and culminating in a teachable HackSpace project with reasonable accuracy. We will put these devices in fridges, near heat sources, near doors, windows, indoors, outdoors, you name it.

The component:

Listed in stores as "Future Electronics B4090K Thermistor 47k 5%"
I think it may be this one
- http://uk.futureelectronics.com/en/Search.aspx?dsNav=Ny:True,Ro:0,Nea:True,N:477-4294920237
- http://uk.futureelectronics.com/en/Technologies/Product.aspx?ProductID=NTCLE100E3473JB0VISHAY8666240
however, the Vishay product may be obsolete and the tolerance is listed as 1.5% rather than 5%

  VISHAY 
   NTCLE100 Series NTC 47 kOhm ±1.5 % Radial Leaded Standard Precision Thermistor
   Mfr Part#:  NTCLE100E3473JB0
   Packaging : BAG 
   Std Packaging Qty: 500
   Min Order Qty: 1
   As low as:  £0.1751  (GBP)
   In Stock:  No
   Type: 
   NTC
   Resistance: 
   47 kO
   Tolerance (%): 
   ±1.5 %
   B-constant: 
   4090 °K
   Temperature Range: 
   -40 to +125 °C

Some Google digging reveals...

http://www.vishay.com/docs/29049/ntcle100.pdf
these thermistors are colour coded
- Yellow Violet Orange Gold
  - B25/85-VALUE = 4090K (+/- 5%) (the gold means 5%)

The simplest circuits and Arduino code...

http://arduino.cc/playground/Main/InterfacingWithHardware#envtture

This is the best code I have found so far - from Thermistor2 but allows us to have our own parameters definition...

 #define NOTTINGHACK_47K 4090.0f,298.15f,47000.0f  // B,T0,R0

#include <math.h>
// enumarating 3 major temperature scales
enum {
  T_KELVIN=0,
  T_CELSIUS,
  T_FAHRENHEIT
};

// manufacturer data for episco k164 10k thermistor
// simply delete this if you don't need it
// or use this idea to define your own thermistors
#define EPISCO_K164_10k 4300.0f,298.15f,10000.0f  // B,T0,R0
#define NOTTINGHACK_47K 4090.0f,298.15f,47000.0f  // B,T0,R0

// Temperature function outputs float , the actual
// temperature
// Temperature function inputs
// 1.AnalogInputNumber - analog input to read from
// 2.OuputUnit - output in celsius, kelvin or fahrenheit
// 3.Thermistor B parameter - found in datasheet
// 4.Manufacturer T0 parameter - found in datasheet (kelvin)
// 5. Manufacturer R0 parameter - found in datasheet (ohms)
// 6. Your balance resistor resistance in ohms  

float Temperature(int AnalogInputNumber,int OutputUnit,float B,float T0,float R0,float R_Balance)
{
  float R,T;

  R=1024.0f * R_Balance / float( analogRead(AnalogInputNumber) ) - R_Balance;
  T=1.0f/(1.0f/T0+(1.0f/B)*log(R/R0));

  switch(OutputUnit) {
    case T_CELSIUS :
      T-=273.15f;
    break;
    case T_FAHRENHEIT :
      T=9.0f*(T-273.15f)/5.0f+32.0f;
    break;
    default:
    break;
  };

  return T;
}
// example of use #1
// reading from analog input 1, using episco k164 definition
// and 10k balance, getting result in celsius

void setup() {
 Serial.begin(9600);
}

void loop() {

 Serial.println("*************************");
 Serial.println("10k Balance");
 Serial.println(Temperature(1,T_CELSIUS,NOTTINGHACK_47K,10000.0f));
 Serial.println("*************************");

 delay(500);
}

I certainly would like one of these data logger devices...

A Processing sketch to receive a number of sensor values on the serial line and do something with them...

int sensorCount = 5;  // max number of values to receive
float[] sensorValues = new float[sensorCount];  // array to hold the incoming values

import processing.serial.*;
Serial myPort;                // The serial port

int BAUDRATE = 9600; 
//int BAUDRATE = 115200; 
char DELIM = ','; // the delimeter for parsing incoming data

PFont fontA;

void setup() 
{ 
  size(200, 200);
  smooth();
  noStroke();
  frameRate(3);
  myPort = new Serial(this, "COM10", BAUDRATE);
  // clear the serial buffer:
  myPort.clear();

  fontA = loadFont("AlbaSuper-48.vlw");
  // Set the font and its size (in units of pixels)
  textFont(fontA, 48);

} 

float x, z;

void draw() 
{ 
  background(100);

  fill(255, 204, 0);
  text(""+sensorValues[0], 20, 50);

 
  float diameter = min(width, height) * 0.75;
  float lastAng = PI;
  // scaling factor on sensor values...
  float val = sensorValues[0] * 2.5;
  fill(204, 102, 0);
  arc(width/2, (height/2 + 50), diameter, diameter, lastAng, lastAng+radians(val));
  
  
} 


void serialEvent(Serial myPort) {
  String serialString = myPort.readStringUntil('\n');
  if (serialString == null)
    return;
  String[] vals = split(serialString, DELIM);
  for (int i = 0; i < vals.length; i++) {
    vals[i] = trim(vals[i]);
    if (i >= sensorCount)
      break;
    println("vals["+i+"] = '"+vals[i]+"'");
    float f = float(vals[i]);
    if(!(""+f).equals("NaN"))
      sensorValues[i] = f;
  }
}

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