Miles's Thoughs

 I’ve recently had two people ask me the same question about how I took some recent pictures. I sent them mail about it, but I figure I’d share with the two people that are subscribed to this blog 😉
e  I used a white sheet as the background and two 4×8 vinyl bathroom surround sheets from homedepot. probably $20 each. Note that this is easier if you have a two flashes.  I’ve considered getting a third. 😉 Also this one:
This one I took with a black sheet:

To take the pictures with the white background, you need to flashes, but you can get a good start with just one:
$21 lightstand  http://cgi.ebay.com/200CM-Light-Stands-Photo-studio-/110694199117?pt=LH_DefaultDomain_0&hash=item19c5e36f4d
$14 bracket http://www.amazon.com/Mounting-Bracket-Strobist-Umbrella-Fancier/dp/B003TY6GWU/ref=sr_1_4?s=electronics&ie=UTF8&qid=1306780897&sr=1-4
  $5  umbrella http://cgi.ebay.com/33-Studio-Flash-Translucent-White-soft-Umbrella-83cm-/170644198871?pt=LH_DefaultDomain_0&hash=item27bb2fd5d7 $28 wireless trigger http://cgi.ebay.com/RF-602-2-4GHz-Wireless-Remote-Flash-Trigger-CANON-/250775783838?pt=Camera_Camcorder_Remotes&hash=item3a6366c99e $68 total. To learn how to do this, read this series of blog entries: http://strobist.blogspot.com/2006/03/lighting-101.html This group has great discussion: http://www.flickr.com/groups/strobist Lot’s of examples of what you can do. White background http://www.zarias.com/white-seamless-tutorial-part-1-gear-space/ while you’re at it, this blog is very interesting as well.
http://petavoxel.wordpress.com/category/megapixel-madness/ The explanation of the physics of megapixels vs sensor size. my next flash purchase will be one of these: he flash is this one  

As part of my photography hobby, I use NiMh AA batteries in my flashes. Occasionally, it happens that my flash won’t recharge very quickly, if at all. I’d always believed this to be caused by having one or two dead/weak batteries. Most flashes use 4 cells in series. If one is no good, nothing works. Most sites I’ve read recommend always using batteries as a set. Always use the same four together. I wasn’t doing this and that’s probably a large part of my problem. But now I have ~20 batteries of unknown condition. How to test? After googling around a bit, I came across some Arduino based testers. The ones I found had some great features, like the ability to handle battery packs, identify batter type and more. I just needed a AA NiMh tester that could handle multiple cells. In the end, I brewed my own. My design is pretty basic. I discharge a cell through a 1 ohm resistor. Since these batteries typically run at about 1.2v while loaded, this translates into approximately 2 hours to discharge. Since I am discharging each cell independently, I don’t need to worry about over-discharge. The green wires measure the voltage drop across the resister which is used to track the current flowing. The code checks the current every 10 seconds and displays the milli-amp-hours. The lcd displays the four values. The software considers a cell discharged when the voltage drops below .6v. After this when it sees a voltage above .8v it resets the data for that channel. These are probably not the best values to use, but they work. As a voltage reference, I use 4 1kohm resisters in series and tap off of one of them. This yielded a ref voltage of 1,237 when measured with my voltmeter. I’m not too concerned about accuracy. I just want consistency to enable me to pair cells into sets of four.   Here’s the source code #include “Streaming.h”
#include <LiquidCrystal.h> float aref = 1.237;
int interval = 10; // Connections:
// rs (LCD pin 4) to Arduino pin 12
// rw (LCD pin 5) to Arduino pin 11
// enable (LCD pin 6) to Arduino pin 10
// LCD pin 15 to Arduino pin 13
// LCD pins d4, d5, d6, d7 to Arduino pins 5, 4, 3, 2
LiquidCrystal lcd(12, 11, 10, 5, 4, 3, 2); void setup()
{
  analogReference(EXTERNAL);
 
  // start serial port at 9600 bps:
  Serial.begin(9600);
  
  lcd.begin(16, 2);
  
  lcd.clear();                  // start with a blank screen
 
} class Battery {
  public:
  enum States { EndDischarge, Discharging };
  Battery(int pinin, float res) {
    pin = pinin;
    resistance = res;
    reset();
  };   void reset() {
    state = EndDischarge;
    as = 0;
    elapsed = 0;
  }; 
 
  float getmAh() {
    return float(as*interval)/3600.0*1000.0;
  };
 
  States getstate() {
     return state;
  }
 
  int getpin() {
     return pin;
  }
 
  void tick() {
    int val = analogRead(pin);
    float volts = float(val)/1024.0*aref;
    float current = volts/resistance;
   
    switch (state) {
     case EndDischarge:
      if (volts > .8) {
        reset();
        state = Discharging;
       
        Serial << pin << ” battery connectedn”;
        break;
      } 
      return;
      break;
    
     case Discharging:
      if (volts < .6) {
         Serial << pin << ” battery discharged with ” << getmAh() << ” mAhn”;
         state = EndDischarge;
         return;
      }
      break;
     
    }
   
    elapsed += interval;
    as += current;
   
   
    Serial << pin << ” volts ” << volts << ” current ” << current << ” mAh ” << getmAh() << “n”;
  };
 
  private:
  int pin;
  float as;
  long elapsed;
  float resistance;
  States state;
}; Battery batteries[] = {
    Battery(0, 1.0),
    Battery(1, 1.0),
    Battery(2, 1.0),
    Battery(3, 1.0)
}; void loop()
{
  delay(interval*1000);
 
  lcd.clear();
  for(int i=0; i<sizeof(batteries)/sizeof(Battery); i++) {
    batteries[i].tick();
    lcd.setCursor((batteries[i].getpin()%2)*5, batteries[i].getpin()/2);
    lcd.print(int(batteries[i].getmAh()));
    if (batteries[i].getstate() == Battery::EndDischarge) {
      lcd.print(“d”);
    }
  }
}

So I’ve been wanting to build the Gingery series of metal working tools, starting with the lathe. As part of that, I’d need some v-belt pulleys. I could buy them, but that seems a bit expensive.Why buy, when you can build? So I built a jig for cutting the v-groove and and it’s turned out pretty good. The inside angle of is 40 degree, so the jig hold the material at 110 degree relative to the table, giving the required 20 degrees on either side. Operation is just like cutting a circle on the tablesaw, but with a different angle.
When I attach the pulley to the shaft, note that I’ve drilled and tapped a hole. I have a 1″ 1/4-20 screw on either side. One of them is visible and the other is hidden.

I’ve been wanting to do some metal casting ever since I came across thisseries of books which teaches how to build ones own metalworking machinery. Metalworking is not something I’ve tried before and I don’t really have a need for it (yet, perhaps), but the projects seem cool.In order to build said machinery, you have to first learn how to cast metal and there’s actually a fair amount of interest in this one out there. My favorite link isthis one andthis page in particular. So I got some old broken down lawnmowers from a friend who was moving out of her house and I got an old toyota tranmission from someone off craigslist. Thankfully, I’ve got my big rocket stove to get the larger pieces hot enough to break them into more manageable bits. Aluminum melts at 1220 degrees fahrenheit. That seems pretty hot, but it’s actually not. If you take a wood fire and blow air on it, you can reach that. If it sounds like an airplane is about to take off, you’re in good shape. My furnace is made out of an old piece of wood stove venting. The inner space was filled with a simple mix of concrete, fireclay, sand, and perlite. I filled the outer space with just perlite to act as insulation. What do I use for fuel? Used motor oil of course. I had some “laying around” from the last couple times I changed the oil in my truck. The link above as well as this one prompted me to try it. As always, click the pictures below for larger images. The basic idea is to blow air into whatever it is you’re burning. In my case, I start with some charcoal, maybe 10 or 15 pieces. If you look closely at the picture on the right, you’ll notice a length of 1/4″ copper tubing sticking out both ends. The two bolts you see and one that you don’t hold the tubing centered. The left end is connected to some plastic tubing, through a valve to the kitty litter bucket on the chopping rounds. To connect to the kitty litter bucket, I simple drilled a hold a little smaller than the 3/8″ nipple (I wrote nipple, huh huh) Also notice the small fireplace rack looking thing in the upper right corner of the picture on the right. That’s to give the flame some room to combust. It’s just rebar bent and welded. To lift the “crucible” (AKA the 5″ tubing) I used pliers. While this works, I need to rig up a better way to maneuver the thing. Here’s setup again fully assembled. This one has the valve I used at first. The adjustment is very sensitive. I quickly go from not much action to full liftoff. I now have a metal ball valve. still very sensitive, but less sticky. Also, note the first ingots. Here are some shot of the foundry running.  

It’s been a while since my last posting, but I have been working on my rocket stove and I’d say it’s just about done. My first stove was pretty small, measuring 6″ in diamater inside and 10″ outside. Well, the new one is made from a 55 gallon drum.One of the big lessons from the other stove is that airflow is key. I recently had the furnace in my house replaced and I had the guys leave the old one behing so I could scavenge for parts. One of these parts is a blower fan. Next, I needed a way to distribute the air into the combustion chamber (how’s that for technical jargon?) If you look closely or click on the image for a larger view, you’ll see that I’ve drilled holes on one side of each of the tubes. This is also to cause a swirling. I want the air to move around as much as possible before leaving. Here are some shots of the barrel from below. This should give you a better idea of what’s going on. next And here’re a couple inside shots.
Next, I created some forms so I could line the inside with a cement, sand, perlite mix. The perlite is to make it a bit insulating. Instead of removing the forms, I just burned them out. Here are some shots of the stove in action.

A last optimization on the stove is a lid. I haven’t tried it yet, but I think it will help it burn even better.
Stove performance So far, I’ve been very pleased with how the stove operates. I’ve been able to burn sawdust, woodchips, firewood and construction scraps. The main issue is with the sawdust. The problem there is that as the upper layers of sawdust turn to ash, it seals away the unburned sawdust. The fire dies down a bit and then when I stir it a bit, it fires back up. Figuring out a way to make it into blocks would be neccessary to really make it work with that kind of fuel. Wood and woodchips burn pretty good though. I’m looking forward to seeing how the lid does.

As always, click for larger images. I’ve been wanting to put in some rainbarrels for a while now. Dan, a friend of ours from Robie’s job, has rain water collection at his house and I’ve thought of it ever since. Dan has two 275 gallon liquid “Totes” but I opted for regular 55 gallon barrels because they fit under the deck/porch. First I build some racks to hold and stabilize the barrels. As you can see in the pictures, I made a simple tramel for my jigsaw. It required a bit of adjustment for blade drift. What this means is the the blade of the saw has a certain direction it wants to go and after a while of following a certain trajectory, the blade will curve to the left or right. I”m not talking about the curve of the cut, but a curve in the blade itself. To compensate, I rotated the saw a little bit in the same direction of the blade curve and the blade stayed vertical. Note that Frankie was very helpful.
To connect to the downspouts, I used 2″ ABS (drain) pipes. Because it’s inevitable, the crud comes down the gutters along with the water, I put in some features similar to a septic tank. First, I extented the downspout well into the barrel. I epoxied a 1.5″ length of ABS inside the 2″ I was using. It extends to about 8″ from the bottom. Second, for the exit, I make the water level be a little higher than the exit point. The overall exit is higher than the end of the 1.5″ pipe. What this means is that water and crud are delivered directly to the bottom of the barrel and the crud will either sink or float. If it floats, I don’t want it to be channeled directly to the water exit and that’s why the corner is there. That’s an awful explanation, but hopefully the pics help clear it up. Here are some of the barrels before I dragged them under the porch.

Today is Jovan’s birthday so we went out last night to celebrate. A fun time was had. I’ve got a boatload more pics on my website. 25 years. getting old.

A couple weeks ago, my friends Markus and Liz helped me trim the hedge at my house. It was a big job, taking about 5 hours. I later rented a big chipper and got about 4.5 yards of wood chips. If you look closely at the box of chips, you’ll see steam coming out of the pipe. For more about why the pipe’s there, see: This post on composting Instead of using a ladder, I rigged up a scaffolding on my truck.

Just to give you an idea of how our yard and garden are shaping up.

Spring has arrived and it’s time to plant the vegetable starts. To facilitate this, I built a grow-box. As always, you can click for a larger image. Note that the height of the lights is adjustable.