Friday, November 1, 2013

How I Earn My Living Buying and Selling Appliances on Craigslist

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When Gadgets Should Be Repaired, Not Replaced

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Jalebi An Indian Sweet (Instant Version)

Good Instructable Citizens,  (I am watching Spartacus these days :D)

"Life is a celebration."- Osho

"Life is a celebration, when you eat Jalebies" - Tarun  Upadhyaya  Ha ha :D

Jalebi (Ja as in jump le as in Label bi as in Big).

Jalabies are known as celebration sweet in India. In ancient India, people use to make & distribute Jalebies during weddings, child-birth, victory etc. In present India it is still known to be part of celebration. However the Jalebies are evolved  from just a celebration sweet to an extremely popular Indian sweet, savored across India and Indian subcontinent, from streets to 5-Star Hotels.

A little history (source :Wikipedia)

"Origins of Jalebi can be traced back to ancient India, where it was called Kundalika or Jal-vallika (being full of syrup, which is watery; hence the name). In later dialects of Sanskrit, Jal-vallika became Jalebi which likely arrived in the middle east during the period of Muslim rule, through cultural diffusion and trade from the Indian subcontinent, and its local name Jalebi became Zalebi as Z is more common in middle-eastern languages."

This sweet is so popular that many food companies offer instant Jalebi Mix so that you can make it at home. But I like to make it by my own, fresh and homely. Don't ya? :)

Traditionally, Jalebi requires a fermantation process of 24 hours, but since this version of Jalebi making is instant, it would only need an hour.

As difficult as it may appears to make, in reality it is simple to make :). Lets make this swirly, juicy, crunchy, mouth watering sweet. Keep the vows of your diet aside for a moment and savor this heavenly delight :).

Important information:

Preparation Time: 30 Minutes
Fermentation Time: 1 Hour
Servings: 4 (Grrr.. I had to share ;-))

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Why Exercise Helps You Think Straight

Why Exercise Helps You Think Straight

After a bout of exercise, it's common for people to report that they seem to think a bit more clearly, and even be more creative. Scientific American explains exactly why we think this is.

When you exercise, you increase your blood pressure and blood flow throughout the body. This includes the brain, so when you exercise your brain gets more energy and more oxygen. That's not all though. As Scientific American points out, it's also about longer term effects:

Another explanation for why working up a sweat enhances our mental capacity is that the hippocampus, a part of the brain critical for learning and memory, is highly active during exercise. When the neurons in this structure rev up, research shows that our cognitive function improves. For instance, studies in mice have revealed that running enhances spatial learning. Other recent work indicates that aerobic exercise can actually reverse hippocampal shrinkage, which occurs naturally with age, and consequently boost memory in older adults. Yet another study found that students who exercise perform better on tests than their less athletic peers.

It makes sense when you think about it, and certainly echoes ideas we've heard before about boosting creativity with a walk or just a little exercise.

Why Do I think Better After I Exercise? | Scientific American

Photo by Tobyotter.

Simple 18dof Hexapod, Arduino nano (optionally with pololu maestro)

Here is a simple hexapod that can be built by hand very quickly. The mechanical design is not great, but it is very much in the KISS (keep it stupidly simple) style and should be doable in a weekend for builders of novice to medium experience.

I won't be improving this project any time soon, and people seem to visit my blog from pololu, so I thought I'd go ahead and document it as is. I built this for a sophomore mechanical engineering class at MIT. The wires and six legs make it look complicated, but since the legs are just the same thing repeated 6 times, it's simpler than it appears. Additionally, I did not implement remote controls so all the code runs autonomously (zero input, multiple output system).

Again, this is documentation of the exact steps involved in a semi-working project. No theoretical underpinnings for designing your own hexapod are really explained here.

A complete picture set of the build process exists here: 2.007 Hexapod (Spring 2011). The first few pictures on there are from Aluminum Hexalinkagepod, based off of the Parallax boebot hexapod.
A set of blog posts exists here:
I would specifically recommend this post:
A video explaining the design process in 7 minutes (this instructables goes into the construction but not the design): 
and here is a video of it at the end:

Required items (hardware):
~ Vertical bandsaw (unless you have a lot of patience with a razor)
~ 1/4'' plastic sheet (any reasonable thickness such that the plastic is fairly rigid is fine. I used 1/4'' ABS)
~ About 6'' of 
~ 18 R/C servos (I recommend standard size, I've seen hexapods with the tiny 9g servos, but I think that it would be hard to cut out the holes for such servos by hand), complete with the "+" shaped servo horns and servo center screws that should come with the kit.
I used 6 Hitec-311 and 12 Vigor VS-2 servos because that was what I could scavenge for.
~ Screwdriver
~ 4-40 bolts and locknuts (about 36 of them), or whatever bolts fit through your servo flange holes (the side holes). At least 3/8'' long (enough for the 1/4'' plastic or Al and a locknut to fit on there).
~ Drill and drill bit, ideally also a drill press
~ Ratchet or socket wrench for 4-40 bolts
~ Ideally, a vice or clamp
~ Ideally, a horizontal bandsaw
~Optional: Scrap 2x4 wood
~ Measuring instrument, ruler or vastly preferably calipers
~ Optional: Deburring tool

Required items (electronics): 
~ Arduino nano + breadboard + male headers (for the servos)
~ Either 6 Y-splitter servo cables or a pololu serial servo controller (because the default arduino library only supports 12 servos). I bought an 24ch one, but obviously didn't need all 24 ch, not sure why I did that. >.<;; but I am a conservative person and tend to make large purchases just in case. I'm working on fixing this.
I guess another option is to use an arduino mega.
~ Laptop and usb programming cable appropriate for your flavor of arduino
Male Headers
~ Jumper wires (or single core wire
 suitable for breadboards)
~ Potentially some servo extension cables, female-to-female (and you stick headers in them to make them female-to-male) will come in handy.
~ Breadboard (probably a standard 700 point one is best if you are putting the nano onto the breadboard)
~ Battery pack (I recommend a rechargeable battery flavor of battery pack, as the 18 servos are power hungry)
~~ so you could use a 4xAA battery pack and it'd be fine (the servos are nominally 5V servos but they will run fine at 6v, they will just be a bit twitchy because their circuitry/feedback+controls are designed for 5v use), but if they were alkaline batteries (~3000mAh) they would run out after an hour or less of use

~~alternatively, use a LM7805 chip to regulate a lipo battery pack, which runs at 7.4v, down to 5V. These linear power regulators dissipate the extra energy as heat. For how to use one, please google "7805 tutorial". For instance, see:

Time required: 1 weekend if you just follow my design. I encourage you to design your own hexapod though, once you see how easy it is!

What I used also included a 2.007 (that's a course at MIT) carrier board (looks like This just brings the servo pins out for easy access, as well as has a built in breadboard and a switching power regulator* that can supply up to 3A at 5v, which is probably enough for the 18 servos. It seemed to function a-okay, but my code only ever had 6 servos moving at any given time.

I also made my own battery pack out of some Sanyo UR18650U batteries that were donated to MITERS by Tesla. They are 3.6V, so I made a 2-series, 3 parallel battery pack for a 7.2V 3.3Ah battery pack. This is obviously overkill. At 3.3 Ah and continuously drawing 3A, I could run my hexapod for over an hour. I've found that 10-20 minutes is plenty of runtime for hexapod.

*as opposed to a LM7805 linear power regulator, a switching power regulator is much more efficient.

Note:The hexapod CAD files are for Solidworks 2012 and do not detail nuts and bolts, they are for reference only. I also made a diameter versus radius error on the body, so the body is too big. 

DSCN2177.JPGWe'll be using paper templates to mark out six of the same thing (six legs).

My tibia ended up (after a few iterations) being 1.4x3.75 inches, with holes marked appropriately for where the servo horns would go.

My coxa ended up being 1.42x4.83 inches, with an appropriately sized hole cut out for the servo. The curve on the leg is an arbitrary "it looks nice" curve I cut out directly on the bandsaw (I started out with rectangular legs).

The CAD model you see in the pictures is a later and better (read: smaller and lighter, more appropriate for the servos) revision than the paper templates, and should give you some idea of how it the hexapod is assembled. So ignore the dimensions written on the paper template in the pictures.

Once you are done making the templates, mark them onto the plastic sheet in preparation for cutting. For marking the holes, sharpie bleeds through paper so just line the paper templates up with the plastic and mark the template with sharpie and it should show up on the plastic. I actually cut the legs out and then marked the holes; you can do it in any order.

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MAMEFrame - The battery-powered MAME system

For the Raspberry Pi 
A laptop with an SD card reader

For the controller box
A saw - a table saw is best, but a skilsaw will work
A screw driver to attach the hinge
Sand paper
3/8" Counter sink (optional)
A drill
A set of drill bits - (really, all you should need is a couple around 1/4" and 3/8") for pilot holes when building the controller box and mounting the joysticks
A 6mm hex key to screw in the blind hole screws
1 1/8" hole saw - another type of drill bit that looks like a cylinder with teeth
hacksaw - to cut the hinge and the electronics mount

For installing the wires on the switches
Wire cutters
Wire strippers
Crimping tool (or pliers)


Phase 1 - Controller Box
3/4" plywood good one side (about 1/2 a sheet) $26 per sheet
piano hinge from Lee Valley $7.00
rubber feet $4.00
Wood plugs $3.00
Box of screws (I used 1 1/2" drywall screws) $3.00
(optional) Primer and Paint $51.00
Acrylic, wood or some other thin, non-conductive materialsmall piece (4" x 4") plexiglass, .  This will be used to mount the iPAC and RPi to the inside of the cabinet.
Adhesive feet  $2.00
(optional) Roll of velcro $7.00
Total: $103.00

Phase 1 - Arcade Parts
I get all my parts from Ultimarc ( ) in the UK.  This setup will be for 2 players.  Each player will have a 4/8way joystick, 6 buttons, a player start button, and there will be on Add Coin button.  Ultimarc are great to deal with, and the shipping is really quick.  The controller parts required are:

* I-PAC2 Interface - this component acts as the brains in a way.  All buttons and joystick controls are connected to this, and this interface then plugs into your computer.  The I-PAC works right out of the box using the MAME standard for controls.  It basically takes button pushes, joystick movements, etc, and converts them to keystrokes, then send them to MAME running on your computer.  We will reassign two buttons later on.  It comes with software that lets us do so.  

* 14  Game Buttons - (only 12 are shown) I used the Happ Classic Pushbuttons.  Note that the buttons from Ultimarc come with switches, but some other sources may not.  Don't bother putting the switches on your buttons until they are in the controller platform.  The switches that come from the Happ buttons from Ultimarc are E-Switch.

*  1 of each Player Start 1 and 1 Player 2 start Buttons - They come in white and black

* 2  Add Coin Button - This is really just another Happ button like above, but I picked a different color.  Strictly speaking, you can get away without this, as you can program the I-PAC to send the 'add coin' keystroke using existing buttons and movements.  I think by default it's Player 1 start + Player 1 button 1.  I wouldn't recommend it though.  Just buy the extra button.

* 2  Mag-Stik Plus Joysticks - I picked these because they can easily be changed from 4 way to 8 way.  Some games require 8 directions and some don't really work well with 8 directions enabled, so it's nice to be able to switch back and fourth without having to get at the bottom of the joystick.  These are expensive.  If you want to save some cash, get a cheaper joystick.

* Mounting hardware for Mag-Stik Plus - A nice kit for mounting the joystick to the controller platform, assuming your platform is wood.  You could probably get away without this if you wanted to save a few bucks.  Note: If you order this, be sure to get size that matches your joystick (6mm for the Mag-Stik)

* 1  Daisy-Chain Harness - again, if you want to save a few bucks, you can probably do without this, but this is a really nice premade kit that just allows you to connect the ground from all the button switches together.  We'll cover this more later, but each switch (and direction on a joystick) has a ground, a Normally Open, and Normally Closed.  When we wire these, all the grounds can be chained together from switch to switch, but the Normally Open  connector must be connected directly to the IPAC.  This is why we have both the Daisy Chain, and other crimp connectors.  Note that this harness must match the size of the switches on your buttons.  This may differ by brand, but it 6.3mm for the Happ buttons I'm using.  Also note that switches are included with the Happ buttons listed below.

* 1 pack Crimp Connectors - These are the connectors that connect to the joysticks and switches.  As with the daisy-chain harness,  these connectors must match the size of the switches on your buttons.

Total parts list (prices in Canadian Dollars):

Classic Pushbuttons from Happ Controls. Orange 2 x 1.95 = $3.90 (only one shown in photo)
Classic Pushbuttons from Happ Controls. Red 1.95 x 4 = $7.80
Classic Pushbuttons from Happ Controls. Blue 1.95 x 4 = $7.80
Classic Pushbuttons from Happ Controls. Black 1.95 x 4 = $7.80
Classic Pushbuttons from Happ Controls. White 1.95 x 4 = $7.80 (not shown in photo)
Crimp Connectors 6.3 mm 9.00 x 1 = $9.00
Daisy-Chain Harness 6.3mm (1/4in) Connectors 14.00 x 1 = $14.00
Joystick Mounting Kits 6mm for Mag-Stik 7.00 x 2 = $14.00
Mag-Stik Plus Red 33.00 x 2 = $66.00
Start Logo Pushbuttons Black. Start1 1 x 2.90 = $2.90
Start Logo Pushbuttons Black. Start2 1 x 2.90 = $2.90
Sub-Total: $134.17
Shipping: $27.00
Total: $161.15

Note this cost doesn't include the two white buttons, or the second Coin button.  I added the 2 player coin later in the project after I realized that some games actually require the player 2 coin in order to go into 2 player mode.  Also, the two white buttons are used as Enter and Escape.  These are absolutely required either, but I highly recommend them.  They make the MAME controller playable without having to know the secret combinations for Enter (Player 2 Start + Player 1 left) and Escape (Player 1 start + Player 2 Start).

Phase 2 - Parts for the Raspberry Pi

Raspberry Pi from Lee's Electronics 1 x $45.00 (for Phase 2) - this is the amazing little computer that will run MAME.

8GB SD Card 1 x $9.99 - There's debate about the best class of card to use.  I'm using a cheap class 4.  This will be running the brains of the system, and I've read a few articles that discuss how different classes of cards affect speed.

Micro USB B to USB A cable 1 x $9.99 - This will provide the power from the projector (USB A) to the RPi (Micro USB).  Don't mistake Mini USB for Micro USB.  

Total Phase 2 Costs $64.98

Phase 3 - Parts for the Projector

1/4" x 1 1/4" bolt to mount the projector

Self Adhesive closed foam weather stripping for the projector mount $4.48

(Optional) 1/8" Headphones stereo splitter 1 x $4.00 (I got mine from Lee's Electronics, but I can't find a link on their site)

(Optional) Old headphones that you can cut apart (free) or 1/8" Headphones stereo extension cables 2 x $16.0 - I put the headphones in Phase 3 because I connect the splitter to the projector rather then the RPi.  I noticed that I was getting a lot of noise when I ran the audio directly from the RPi, however, the audio from the project was fine.  I think maybe because it's a digital signal from the HDMI cable, as opposed to the analog signal from the RPi?  I don't really know.

Brookstone Pocket Projector from 1 x $329.00 (Phase 3) - this is the key to making the system portable and battery powered, as the projector contains a rechargeable battery that can power the Raspberry Pi and the iPAC.
Plus taxes and duties: $38.46
Plus shipping: $36.84
Total projector cost: $395.79

Total Phase 3 Cost: $420.27

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