Awhile ago I say this article on Hackaday http://hackaday.com/2014/12/30/3d-printing-technique-friction-welding/ on how to quickly and easily use friction welding on 3D prints.

I recently printed out a model of the Hubble Space Telescope to honor 25 years in space.  http://nasa3d.arc.nasa.gov/detail/HST

The print was in several pieces and it need some assembly.

The technique is quite simple.  Put a piece of filament into a Dremel and push it into a joint.  You will need a smaller collet as the default one is too big.  I happened to have one from a set I purchased years ago.  Insert the filament with about 3/8″ sticking out.  Don’t worry if its not exactly straight it will fix itself with a little pressure.

I ran the speed on the Dremel at 3-4 which seemed to work fine for me.

Here is before: And after:
Here are some more joints:

It works great it is quite easy and it seems to form a great bond.  Be ready to stop the Dremel and pull more filament out especially when you are filling a big joint.

I have a two year old and she likes to play inside one of the kitchen cabinets.  I would imagine that it gets dark in there when she closed the door, so I decided to puts some lights in there.  Being a 2 year old she likely to burn through some batteries so I though I could do a bit better than a simple on/off switch.

To be honest I have been wanting to do something with a 555 for a long time.  I picked one up from Radio Shack back in January 2003.  Now there is a need, so now is the time.

I basically used this article as a basis http://www.instructables.com/id/555-Timer/?ALLSTEPS.

I easily had all the parts so it was just a matter of assembly.

I will be using the 555 in the mono-stable mode circuit.

The only differences I made is that the control resistor shown here as a 10k ohms has been replaced with a 500k potentiometer/preset and the control capacitor shown here was replaced by a 330uF cap (since that’s the closest I had).  These values workout to a timeout of 0-181.5 seconds, right in the range that I was looking for.

In this case I also decided not to go all out and do a circuit diagram an etch a PCB.  This is a simple enough circuit I can just use some perfboard without the fuss.

Here is my result. 
It actually came out quite nice.  It has one button that starts the timer and turns on the 3 white LEDs.   The button does on nothing while the lights are on so in order to keep them on you have to hit the button every time they turn off.

LEDs stand off the board for max dissipation in a case I will make next.

Bottom side

Massive 330uF radial cap and an 805 SMD 10pF cap under it.

This will be powered by a 9v battery which will hopefully last a while at 2min duty cycles.  I am not sure what the current draw is when idol (I may measure this later) but I think I will add an on off slider switch.

The next step is to make a case.  I have some ideas on what I want to do with the case but I do know that it is going to have to be rugged enough for a 2 year old to be pounding on it every 2 mins.  I was thinking that would be similar in design to the staples easy button but I will see how that pans out.

That’s all for now hopefully I can get the case done soon and I will post the second update to this post once it is done.

So I have been neglecting my temperature and humidity sensor.  I haven’t had it in my filament box because the battery does not last long enough and it occasionally hangs up.  I am attempting to address the latter first.  I added 4 more leds (total of 5) to try to find where in the code it is hanging.

Here is the new config:

And the code:

// This #include statement was automatically added by the Spark IDE.
#include "idDHT22/idDHT22.h"
#include ;

// declaration for DHT11 handler
int idDHT22pin = D4; //Digital pin for comunications
void dht22_wrapper(); // must be declared before the lib initialization

// DHT instantiate
idDHT22 DHT22(idDHT22pin, dht22_wrapper);

char message[75]={0};
//char shortmessage[62] ={0}; //events have a limit of 63 bytes
String rmessage = "";
String smessage="";
double Humidity =0;
double degF = 0;
double degC = 0;
double DewPoint = 0;
double DewPointSlow = 0;
int result;
int greenled = 5;
int redled = 3;
int orangeled = 2;
int yellowled = 1;
int blueled = 0;

void setup()
{

	pinMode(greenled, OUTPUT);
	pinMode(redled, OUTPUT);
	pinMode(orangeled, OUTPUT);
	pinMode(yellowled, OUTPUT);
	pinMode(blueled, OUTPUT);
	
	Spark.variable("message", &message, STRING);
	//Spark.variable("Humidity", &Humidity, DOUBLE);
	//Spark.variable("degF", &degF, DOUBLE);
	//Spark.variable("degC", &degC, DOUBLE);
	//Spark.variable("DewPoint", &DewPoint, DOUBLE);
	//Spark.variable("DewPointSlow", &DewPointSlow, DOUBLE);
}
// This wrapper is in charge of calling
// mus be defined like this for the lib work
void dht22_wrapper() {
	DHT22.isrCallback();
}
void loop()
{

	digitalWrite(greenled, HIGH);   // turn the LED on (HIGH is the voltage level)
  
 
 
	//Serial.print("\nRetrieving information from sensor: ");
	//Serial.print("Read sensor: ");
	//delay(100);
	DHT22.acquire();
	digitalWrite(redled, HIGH);
	while (DHT22.acquiring());
	
	digitalWrite(orangeled, HIGH);
	result = DHT22.getStatus();
	switch (result)
	{
		case IDDHTLIB_OK:
			//Serial.println("OK");
			break;
		case IDDHTLIB_ERROR_CHECKSUM:
			//Serial.println("Error\n\r\tChecksum error");
			break;
 		case IDDHTLIB_ERROR_ISR_TIMEOUT:
			//Serial.println("Error\n\r\tISR Time out error");
			break;
		case IDDHTLIB_ERROR_RESPONSE_TIMEOUT:
			//Serial.println("Error\n\r\tResponse time out error");
			break;
		case IDDHTLIB_ERROR_DATA_TIMEOUT:
			//Serial.println("Error\n\r\tData time out error");
			break;
		case IDDHTLIB_ERROR_ACQUIRING:
			//Serial.println("Error\n\r\tAcquiring");
			break;
		case IDDHTLIB_ERROR_DELTA:
			//Serial.println("Error\n\r\tDelta time to small");
			break;
		case IDDHTLIB_ERROR_NOTSTARTED:
			//Serial.println("Error\n\r\tNot started");
			break;
		default:
			//Serial.println("Unknown error");
			break;
	}
    
    digitalWrite(yellowled, HIGH);
    Humidity = DHT22.getHumidity();
    degF = DHT22.getFahrenheit();
    degC = DHT22.getCelsius();
    DewPoint = DHT22.getDewPoint();
    DewPointSlow = DHT22.getDewPointSlow();
    
    rmessage = "";
    smessage = "";
    sprintf(message, "{\"Humidity\":%3.4f,\"degF\":%3.4f,\"degC\":%3.4f,\"DewPoint\":%3.4f,\"DewPointSlow\":%3.4f}", Humidity, degF,degC,DewPoint,DewPointSlow);
    //rmessage = "{\"Humidity\":" + doubleToString(Humidity,4) + ",\"degF\":"+ doubleToString(degF,4) + ",\"degC\":" + doubleToString(degC,4) + ",\"DewPoint\":" + doubleToString(DewPoint,4) +",\"DewPointSlow\":" + doubleToString(DewPointSlow,4) + "}";
    //message = doubleToString(Humidity,4) +","+ doubleToString(degF,4) +","+ doubleToString(degC,4) +","+ doubleToString(DewPoint,4) +","+ doubleToString(DewPointSlow,4);
    //rmessage = "I hate this sooooooo much";
    
    
    //smessage = doubleToString(Humidity,4) +","+ doubleToString(degF,4) +","+ doubleToString(degC,4) +","+ doubleToString(DewPoint,4) +","+ doubleToString(DewPointSlow,4);
    //Spark.publish("TempData",smessage);
    
    digitalWrite(blueled, HIGH);
    delay (2000);
    
    digitalWrite(greenled, LOW);
    digitalWrite(redled, LOW);
    digitalWrite(orangeled, LOW);
    digitalWrite(yellowled, LOW);
    digitalWrite(blueled, LOW);    // turn the LED off by making the voltage LOW
    
	//Spark.sleep(900);
	delay(30000);
}

//Rounds down (via intermediary integer conversion truncation)
String doubleToString(double input,int decimalPlaces){
    if(decimalPlaces!=0){
        String string = String((int)(input*pow(10,decimalPlaces)));
        if(abs(input)<1){             if(input>0)
            string = "0"+string;
            else if(input<0)
            string = string.substring(0,1)+"0"+string.substring(1);
        }
        return string.substring(0,string.length()-decimalPlaces)+"."+string.substring(string.length()-decimalPlaces);
    }
    else {
        return String((int)input);
    }
}

If you are interested here is a graph of the data:

If you read my previous post you can see I was using powershell to write data to a CSV file locally on my PC.  This was not a great solution because my PC had to be running at all times in order to get the data.  I decided to use my Raspberry Pi as a server to collect the data and have it push the data to Google Docs.  Here is what I came up with:

#!/usr/bin/python
import time
import gdata.spreadsheet.service

import urllib2
import json
import time

##########Make Changes in this section
#the URL for your spark core
URL = 'xxxxxxx'
#Your gmail email to login to google docs with
email = 'xxxxxx'
#you gmail password
password = 'xxxxxxxx'

# Find this value in the url with 'key=XXX' and copy XXX below
spreadsheet_key = 'xxxxxxx'
# All spreadsheets have worksheets. I think worksheet #1 by default always
# has a value of 'od6'
worksheet_id = 'od6'

#########Done with the changes

while True:
 response = urllib2.urlopen(URL)
 response = response.read()
 response = json.loads(response)

 result = response["result"]
 result = json.loads(result)

 Humidity = result["Humidity"] 
 degF = result["degF"]
 degC = result["degC"]
 DewPoint = result["DewPoint"]
 DewPointSlow =result["DewPointSlow"]

 weight = '180'

 spr_client = gdata.spreadsheet.service.SpreadsheetsService()
 spr_client.email = email
 spr_client.password = password
 spr_client.source = 'Python runing on pi'
 spr_client.ProgrammaticLogin()

 # Prepare the dictionary to write
 dict = {}
 dict['date'] = time.strftime('%m/%d/%Y')
 dict['time'] = time.strftime('%H:%M:%S')
 dict['humidity'] = str(Humidity)
 dict['degf'] = str(degF)
 dict['degc'] = str(degC)
 dict['dewpoint'] = str(DewPoint)
 dict['dewpointslow'] = str(DewPointSlow)
 #print dict

 entry = spr_client.InsertRow(dict, spreadsheet_key, worksheet_id)
 if isinstance(entry, gdata.spreadsheet.SpreadsheetsList):
 print "Insert row succeeded."
 else:
 print "Insert row failed."
 time.sleep(300) # delays for 300 seconds 

You need to install the gdata python library here is how to do that (thanks to  http://www.mattcutts.com/blog/write-google-spreadsheet-from-python/)

mkdir ~/gdata
(download the latest Google data Python library into the ~/gdata directory)
unzip gdata.py-1.2.4.zip (or whatever version you downloaded)
sudo ./setup.py install

This script just loops forever and sends an update to the spreadsheet every 5 mins (this might be too often).

I might get fancy and make this a service but for now you can just run it in the background with &

This project is still not done for me.  Next I will be working to Reduce the power consumption by using sleep mode of the core Spark.sleep().  This puts the core in low power mode for a time.  In order to do this I need to change the core script to push data instead of updating all the time.  To do this I will use Spark.publish() to publish an event when it takes a reading.  Then the script can pull that event when ever it gets around to it.

Here is a graph of the sensor data I collected with the sensor in the box.

The battery only lasted about 46 hours.  I would consider this the worst case for the battery usage since I was not doing anything to reduce consumption.  One simple thing to do is to use the Spark.sleep() instead of just delay() that I am using now.  This will put the core into sleep mode with low power consumption.  I am testing this now to see how much it helps.

The next big thing to do is to push the data instead of having the core serve the data.  This way the core can be sleeping and only wake up when a reading is needed.  This seem easy to do also using the Spark.publish() which generates an event that can be collected. There is a nice write up on on how to increase battery life https://learn.adafruit.com/low-power-wifi-datalogging/battery-life-and-current-consumption

I will post a follow-up once I get more data and do more tests.