Know How...

Jul 16th 2015

Know How... 152

Megabot, Grow Bacteria and Flying the KH250

Find out just how much bacteria is living on your devices.
Although the show is no longer in production, you can enjoy episodes from the TWiT Archives.
Category: Help & How To

MegaBots are coming and it's going to be the U.S. vs. Japan, find out what kind of bacteria is living on your phone, and flying the KH250.

If you were at Maker Faire in San Mateo, you probably saw the MegaBot.
* A 12-ton machine with dual cannons and dual pilots. (One controls the movement of the robot, the other controls the weapons.)
* The MegaBot is the brainchild of Matt Oehrlein & Gui Cavalcanti
* They originally tried to kickstart the project -- It was about to fail, but then Autodesk stepped in and financed the remainder of the project

* They had the first prototype at Maker Faire in San Mateo (We just missed it by a day because of TNSS)
* They call it "America's first fully functional piloted robot"
* And of course, they added really big guns

They want to perfect the design, then open source it
* They want others to build robots that will eventually form a MegaBot sports league!
* The'd battle with paint guns.

** Of course... what good is a ass-whooping robot, if it doesn't have something to whoop?

They called out the Kuratas Team
* In a video they posted on YouTube the MegaBot team challenged the Japanese "Kuratas" team, led by CEO Kogoro Kurata to a fight.
* In their word, "We have a giant robot, you have a giant robot... you know what has to happen!"

* It's Powered by a 24 HP gas engine that drives a 2500psi Hydraulic System
* 20 Actuators
* 13 Joints
* Rides on two sets of treads
* Can hunker down to 11-1/2 feet, but then rise to 15 feet
* Can fire 3lb paint cannon balls at 100mph
* 100 days of construction
* 35 People
* $175,000

In a response video the creator of the Kuratas (Kogoro Kurata) said, "It's interesting, but come on guys, make it cooler"
-- They actually accepted the challenge
-- He said it was "Very American" because they just built something big and put guns on it.
-- He also said that THEY must win it because "Giant robots are Japanese culture"

** However, he sent a challenge of his own... that they should stick to Melee Combat instead of just mounting a bunch of guns.

The MegaBot Mark II is 15 feet and 12 tons -- and uses tracks
The Kuratas is 12 feet tall and 9 tons -- and uses wheels

Bacteria Growth Experiment

* If you want a RELIABLE way to know how much and what kind of bacteria is growing on the surfaces in your home/office/car/etc. then you want to perform a Bacterial Growth Experiment
* Basically, you place a sample of the bacteria into a sterile growth medium in order to promote the formation of bacterial colonies.
-- The "Morphology" (size, shape, pigmentation) of the colonies that form will tell you what kind of bacteria is growing

To do this experiment, we need to use Plates, or "Petri Dishes"

If you're going to make your own plates (fun experiment) then you'll need a few things
-1. Sterile Petri Dishes $10.95
-2. Nutrient Agar $9.50
-3. Sterile Cotton Tipped Applicators $6.75
-4. Hotplate $15.08
-5. Pyrex Flask (1L) $11.99
-6. 70% Isoprophyl Alcohol $6.00

You could also just get a Bacterial Growth Kit
-1. Nutrient Agar + 10 Petri Dishs + Cotton Swabs $19.95
-2. Hotplate $15.08
-3. Pyrex Flask (1L) $11.99
-4. 70% Isoprophyl Alcohol $6.00

Or just skip it all and get pre-made, sterile plates
-1. Pre-Poured Agar Plates + Swabs $15.80

1. Glass Stiring Rod
2. Laser Thermometer
3. Flame

Now let's explain what we're going to do with all that stuff:

The Agar:
* Agar is a complex nutrient solution that supports the growth of many different types of bacteria (Typically Soy, with some gelatin and perhaps some sheep's blood)
* It needs to be STERILE. Otherwise, we may get growth on our plates from organisms we didn't introduce
-- That would render the experiment invalid
* You can get two easily-made growth mediums
-1. Powder that you mix with water and boil
-2. Gel that you microwave until liquid, then pour

Sterile Petri Dishes
* This is the container for the agar
* Like the agar, we need them to be sterile, do don't open the package until you're going to use them, and don't open the petri dishes unless you're activelly putting something into them (either the agar or the sample)

The Pyrex Container, the alchohol and the Sterile Swabs
* We need something to heat & mix the agar, then to transfer samples into the ready medium
* Like the Agar and the Petri Dishes... we want them STERILE!
* Don't open the swabs until it's time to sample
* Clean the container with 70% iso alchohol

Now let's make our plates:

1. Sterilize the flask or beaker with a solution of 70% Iso Alchohol (Let it dry)
2. Measure the agar and distilled water into a flask or beaker
** 200ml of agar makes 10 plates
3. Sterilize the glass mixing rod
4. Stir the mixture with the sterilized glass rod until boiling
5. Boil for 1 minute, then remove from heat
6. Using the laser thermometer, monitor the temp of the mixture. When it falls to 45 degrees, it's ready to pour. (It will set at 30 degrees, so you need to pour it before then.)
7. Open each petri dish, pour in agar until it's 1/8" to 1/4" deep - Cover each dish immediately
8. Allow the agar to cool and set.

** If you're going to store the Agar, stack them UPSIDE DOWN in a refrigerator (NOT A FREEZER)
-- You want them upside in order to prevent condensation from the lid from dropping down onto the surface of the agar
** Remember, these are STERILE plates. Don't open them, touch them, or otherwise disturb them until you need them.

Your Questions, Our Answers

In professional labs, they're run their agar dishes through an autoclave:
- Typically they'll heat the media at 240 degrees F, 15PSI for 15 minutes.

Network help
-- Joseph Sacco
"I want to move my router to a more exposed location, like my living room but I do not want to mess of wires to come with it. I have a Roku 3, Tablo DVR and a Western Digital My Book Live that all need to be connected to it. My plan is to run one ethernet cable between the router and the switch, that would be located in a nearby entertainment cabinet and connect my devices to the switch. I went to and looked at the netgear switches. They make managed switches, unmanaged switches and smart switches. Which one do I need, and can I connect the Ethernet cable from my modem into the switch or does that need to go directly into the router."

* Let's talk about network design

Getting your Windows 8 Install Key
-- Jim Sauber
"Fr Robert mentioned in a recent podcast a utility to retrieve the Product Key from an installed copy of Windows, but I don't remember. I am leery of downloading anything without a recommendation. Any recommendations for extracting the Product Key for a running Windows device? Thanks in advance."

Go here:

Here... hold my beer... (Too much power?)
-- David Keeler
"Silly question! Any reason I can't use a 5500 may 14.8V 47 battery on my HK 450? I believe I'll have to use my I inch props not 10 but can he KK handle the increased volts? My other batteries are only 11.7 volts I believe so thought I'd embarrass myself now and not just plug it in to see what happens...."

iFixIt with iFixIt
-- Emilio Morla
" quick tip, the small screwdrivers you get in the ifixit kits are great to tighten you prop nuts."

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