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Sunday, March 23, 2014

iFood - bread Bodini

Well, technology is my world, but I'm a human being  too, and one who loves to eat.
This blog is technical oriented, preparing food is an art but involve technology too ... OK OK, today I'm feeling to share one of my recipes.
When I have time or when I'm in the mood for bread or pizza, the only way to satisfy such mood, is to prepare the bread or pizza by myself.
I love to cook many other things, on my Pinterest table "iFood" i show something ... if you are curious enough to see that :)

Bodini's bread and pizza recipe

Example of bread obtained with this recipe

Tools

  • Bread machine.
    To prepare the dough, use a bread machine.
    Nothing special, almost every generic low cost bread machine will work.
    Just be sure that it can prepare the 2 pounds loaf. Usually such kind of bread machine cost around $40.
  • 2 cups Pyrex to measure liquids.
  • Set of measurement spoons, from 1/4 tsp to 1 tbs
    tsp = teaspoon
    tbs = tablespoon
  • Set of “cups” to measure the flour. Usually these sets goes from 1/4 Cup up to 1 Cup
  • wooden mattarello
  • dough cutter 
  • sprayer for water
  • round cutter (for “panini”)
  • rectangular nonstick baking trays for the bread.
  • Round nonstick baking trays for pizza. Much much better if they have holes, like this one :

Bread/Pizza dough

Ingredients

Ingredients for 20 “panini” or 4 pizzas :
  • 1 ¾ cup room temperature water
    It is strongly suggested to use filtered water, left in a jar for at least a night.
    Impurities will be on the bottom and the water will be at room temperature.
    Never underestimate the quality of the ingredients, especially the water !
    Water with chlorine or other impurities will make difficult to the dough to raise and will leave a sour taste !
  • 2 tsp fine salt
  • 2 tsp sugar
  • Extra virgin oil
    - Bread : pour enough oil to cover ¾ of the water surface
    - Pizza : the oil have to cover the entire water surface
  • 6 cup “normal” flour ( 00 )
  • 3 tsp yeast for bread machine or fast raising

Preparation

Put in the bread machine bake pan the ingredients, in this order :
  • water
  • salt
  • sugar
  • oil
  • flour (level it )
  • yeast



Set the program “only dough”, NO BAKING !
This is IMPORTANT because the quantity of the ingredients is above the baking capability of the bread machine !!

Bread preparation


When the dough is ready in the bread machine, remove it from the baking pan and put it on a table.
In order to prepare “panini”, use the “mattarello” to flat the dough.
Flat it at least to reach ½ inch thick.
Then use a round cutter to cut at least 10-14 “round panini”.
Put them on a nonstick baking tray (is possible to use also the pizza round baking tray).
Leave some space between the panini since they will raise a bit and leave them on it at least for 1 hour (don't go over 2 hours !)
The left over dough can be put together and flattened again, then cut it in triangles and then roll the triangles to form a mini roll.
At the end of the raising time, spray the bread with water and put them in the per-heated oven at 400-405 degrees Fahrenheit for at least 18 minutes.
Check sometime the bottom of the bread. If is yellow/brown is ready.

Remove it from the oven and left it to cool down at least for an hour before to eat it.
The best way to cool it down, is to remove the bread from the baking tray (use mittens or oven gloves, it will be HOT !) and put it in a basket.

The best way to taste it is to cut it in half and then put some salami or cooked ham, a little bit of mayo or some cheese (swiss cheese will be great).

It is possible to put the bread in the freezer.
Put it in small quantities (4 to 6 paninis) in a 1 gallon freezer plastic bag. Gently squeeze out the air before to seal it.
The bread will last at least two to three months.

To re-heat it, pre-heat the oven to 350 degrees Fahrenheit, then put it still frozen (out of the bag !) for at least 8 to 10 minutes. Will be like just made.

The bread will last at least a couple of days if not put in the freezer.


Pizza preparation


When the dough is ready in the bread machine, remove it from the baking pan and put it on a table.
Create a big roll and divide it in 2, 3 or 4 pieces.
2 pieces if you like a “soft pizza”, 3 for a normal pizza, 4 for thin and crunchy pizza.
The best result is with 3 pieces.
It is also important to considering the type of topping.
Cheese topping will require short cooking time, topping with vegetables or other ingredients will require more time.
A thin crust will be OK for cheesy pizza.
Thin crust will cook MUCH faster than normal crust ! Remember that !

Using the “mattarello” flat each piece in a round shape.
Spray with flour and turn upside down the pizza during this stage, multiple times.
The dimension of the pizza has to match the round baking tray and thus will determine the “thickness” of the pizza.
Put the flatten dough on a round baking tray.

With a spoon put the basic topping (see below) over the pizza. It must be spread uniformly.
When the oven is per-heated (again 400-405 degrees Fahrenheit) place the pizza in it.
The baking will happens in two phases.

  1. Phase one
    Put the pizza with the basic topping on it in the oven at least for 9 minutes (thin pizza) to 12 minutes (thick pizza).
  2. Phase two
    Remove the pizza from the oven and spread it uniformly with a lot of shredded mozzarella cheese.
    Put the pizza back in the oven for at least 9 minutes more.
    Check the mozzarella ! When it start to become yellow/orange the pizza is ready !!
    If the mozzarella does not have yellow/orange spots, then is NOT yet ready !
    Don't over bake it.


Topping


How to prepare the basic topping for almost every type of pizza.
In a container, pour the content of a big can of crushed tomato.
Be careful to use ONLY crushed tomato ! Not crushed tomato with basil, or garlic, or other stuff in it.
Then add some extra virgin oil (a couple of table spoon), salt (two or three tea spoon), sugar (1 or 2 tea spoon), oregano (as much as you like, however too much will make the sauce too sour).
Mix it very well.
These quantities are enough for 4 pizzas

For 4 pizza, you will need also at least 8 to 10 cups of shredded mozzarella.
More if you like a “cheesy” pizza.

Sunday, March 2, 2014

Quality time with my daughter

My daughter this year choose to do something different from the usual "biology" science fair project.
She choose to build an electric motor and do some tests to see how is possible to improve the conversion of electricity into kinetic energy.
So it was natural my direct involvement in this.

The science fair project had some specific guidelines and "things to do", but from a more practical point of view, the first thing to do was  to build a basic electric motor.
We found  a lot of suggestions on the net about how to do so. In the end the choice depended about the availability of material and simplicity of building.
Here a brief video showing the motor running.

video

Oh ... she won the Third place for her category at school :)
She also participated to the regional science fair. Unfortunately the motor broke down during the presentation (see notes "Problems" at the end of this article)

Third place for the category

Building a motor

There are many ways to build an electric motor and there are many types of electric motors.
There are AC motors and DC motors.
The object of the experiment was to show how some components of the motor could affect it's performance, when changed.
So we picked up one of the basic-simple type of electric motor, a DC static magnet rotor motor.
The type of motor we wanted to build, had fixed magnet on the moving part (rotor) and an electromagnet on the base (stator).
Many commercial motors have the electromagnet on the rotor and the fixed magnets in the stator, or both electromagnets for rotor and stator, but they are more complex since it must exists a way to bring the electricity on the rotor, a moving part.

Principle


The type of electric motor we choose to build  is extremely simple.
The idea is to have two or more magnets on the rotor. The magnets need to be "paired", i.e. they need to be aligned to themselves.
This simple schematic can help to understand the principle.
When a magnet is close to the Reed switch (a switch activated by a magnetic field) it powers the electromagnet.
The electromagnet generates a magnetic filed with the same polarity of the magnet glued to the rotor, "kicking" it and thus forcing the rotor to spin.
As soon the rotor starts to spin the magnet close to the Reed switch is going away, thus the electromagnets cease to work.
The rotor however continues to rotate for mechanical inertia until the sequence restart, i.e. magnet close to reed switch, electromagnet activated, kick to the other magnet, and so on.

There are some constrains :
  • the magnets need to be glued on the rotor facing with the same pole
  • the position of the Reed switch must be as much as possible aligned with the position of the electromagnet
  • the distance between the Reed switch and the magnet on the rotor is critical. If too far the Reed switch is not activating.
  • the distance between the electromagnet and the rotor is critical too. If too close the magnet on the rotor "attach" to the electromagnet when it is disabled.


Rotor

The rotor is the part of the motor that "rotates" and, for the experiment, is the part we decided to change in order to evaluate the performance of the motor.
The rotors were  built using an empty thread spool, magnets and office pins.
Two or more magnets (always in pair) were  glued on the spools and two pins were glued on the spool central hole to form the axe.



Gluing the magnets on the spool

The spools with the inserted pins to form the axe

We chose to orient the static magnets on the rotor with the South pole facing out, mainly because the RPM meter sensor works on the South pole of a magnet.
We used a simple app for a smartphone to determine the magnet polarity.

Stator

The stator is, for our purposes, everything around the rotor.
We used a wooden base and wooden blocks to build the support for the rotor, the electromagnet, the Reed switch and accessories (main switch, RPM meter, ecc.)

The basic components of the stator, a wooden base and wooden blocks

The electromagnet was connected to a battery and a Reed switch.
The Reed switch is necessary because we need to turn on and off the electromagnet in order to generate a magnetic field only when a rotor's magnet is close by.

Electromagnet

We needed something metal and an insulated electric wire in order to build a coil around the metal part.
Since we used  using small voltage for the project (up to 4.5 Volt) we needed a lot of wire.
We used a nail as metal core of the electromagnet, with the wire coiled directly around it.
We used a drill to facilitate the winding of the wire around the nail

Electromagnet, Reed switch and wooden blocks

Prototypes

Two prototypes were built.
The first one was built mainly to prove the concepts and experiment positioning the components.
The second prototype was the one used to actually perform the test and it was built differently, since we learned from the first one what NOT to do.

First prototype


The first prototype was built positioning the electromagnet on the top of the rotor and the Reed switch fixed at the base.
The idea was to have the Reed switch easily glued at the base and position the electromagnet on the top, it was easier to adjust the distance between the electromagnet and the rotor.

The first prototype
The first prototype was working however it had many problems, like :
  • the electromagnet was moving, required more strong holding
  • the distance between the rotor and the Reed switch was fixed
  • it was difficult to change the rotor
  • the rotor was not strongly hold on the wooden blocks
  • the electromagnet was too weak
  • the voltage used was too high
In the end we realized it was better to rebuild it with different principles.

Second prototype

The second prototype was built with  the idea to be able to easily change the rotor and position the electromagnet/Reed switch more easily.
The second prototype layout

A new electromagnet was built, using a 3 inches nail and almost 250 feet of wire, held by a wooden block carved to the shape of  the electromagnet.

The electromagnet holder, a wooden block carved to the electromagnet shape

The new layout included also a better support for the rotor and the attachment of an RPM meter.


The second prototype used for the test. The RPM meter is shown on the  lower right corner

The RPM meter


In order to evaluate the motor performance, we decided to use the speed of the rotor.
To measure the rotor RPM we needed a tool, an RPM meter or 'tachometer'.
So I built an easy tachometer using one of the boards I had around.

The experiment

At this point we had everything ready for the experiment.
We had a motor base, capable to support a rotor and an RPM meter.
We built 5 different rotors, changing the type of the magnets and the number of the magnets.

  • Rotor 1
    Two ceramic 0.5 inch magnets - Weight : 12.5 g 
  • Rotor 2
    Two Neodymium 0.5 inch magnets - Weight : 20.9 g 
  • Rotor 3
    Two Neodymium 0.2 inch magnets - Weight : 12.7 g 
  • Rotor 4
    Four ceramic 0.5 inch magnets - Weight : 16.4 g 
  • Rotor 5
    Four Neodymium 0.2 inch magnets - Weight : 14.4 g
We decided to proceed in this way :

For each rotor, we choose to perform the test 4 times.
During each test, we set up the RPM meter, let the rotor run for about a minute to "stabilize" the system and then start a 2 minutes timer.
Every 10 seconds we took a reading from the RPM meter.
In this way we ended up with 5 different set of data, one for each rotor.

Capturing the data

Setting the RPM meter

Reading the RPM meter every 10 seconds
From the readings we created 5 graphs to better compare the performance using different rotors.
Here they are :






All the graphs were built using the same scale, so it was possible to compare them directly.
Looking at them resulted that indeed changing the type of the magnet and the number of magnets, the motor had different performances.

Problems

We also experienced a problem.
After building the second prototype we started to collect data for the experiment.
However some rotors had problems. They were spinning at very low RPM and often they were not spinning at all.
We checked the motor and apparently everything was OK .. only apparently.
In the end we discovered that the Reed switch was defective or damaged somehow and it was not always capable to react to the magnet on the rotor.
We decided to substitute the defective Reed switch with a new one, and all the rotors were behaving as expected.

The same problem happened later, during the regional science fair.
The Reed switch broke down again.  The very probably cause of the broke down is the spike of voltage generated by the electromagnet when the Reed switch opens.
Hooking up an oscilloscope we saw spikes up to 250V. On the long run, spikes like that can warm up the metal of the contacts, bending them and leaving the Reed switch unable to operate correctly.
i.e. on the long run the Reed switch mechanical characteristics are compromised by the sparks generated by the electromagnet generated spikes.

The spike in full view - each vertical block is 50 V

A detail of the spike

The poster


Here a couple of pictures of the poster my daughter prepared for the presentation.