A few months ago I picked up a functioning old soda machine off craigslist. This machine was built in 1977 and has been comfortably vending soda the same way for over 30 years. Thats boring, lets make this retro machine a little more modern!

Vender has its credit functions, and dispense button electronically controlled and has two capacitive touch sensors to dispense free soda if you know the secret place to put your hands. It also has a police beacon light atop of it to signal when someone remotely dispenses a can. All of this is on a platform connected the internet, enabling operation from a website (buyusbeer.com) or my iPhone! It makes for a great living room decoration, and always serves up ice cold soda (and beer).

Since I’m moving out and traveling this summer, me and my roommates are selling Vender on eBay. A portion of the sale goes to support the Kiva foundation. Check it out.

Technical Overview

Control Board

Here’s the Phidget 8/8/8 control board at the heart of Vender. This is used to send signals to the relays, and to react to the input from the touch sensors. The control board is connected to an old P4 computer I was able to scrounge up around MIT. The computer runs all the code that lets Vender interact with the internet.

iPhone Control

Somewhat like my door, Vender can be controlled from my iPhone. I have two buttons on my home screen, ‘Soda’ and ‘Beer’ that perform their respective functions. This is the easiest way to dispense from the machine! Though a number of times I have pushed it while I’m away only to find a warm beer sitting sitting in the machine when I come back.

Credit Relay

Wires going in to the credit pins

Vending machines from this era all equipped with Jones plugs between the coin mechanism and the rest of the machine. The coin mechanism handles the tricky task of accepting money and giving back change, and then just tells the rest of the machine when a soda has been paid for. After trolling the soda-machines.com forums, I learned that to establish credit you just need to momentarily connect pins 1 and 7 on the plug. I snaked two wires to these pins and then connected them with a relay operated from the control board. The original coin mechanism is still plugged in.

Button Relays

Button Relays

The button relays are a bit less elegant. After finding the electrical diagram of the machine from the manufactures website (thanks Fawn Vending Systems!), I cut and stripped the wires coming out of each button’s microswitch. Then I spliced in another loop through a relay so that I can simulate a button press from the control board. The microswitches are still connected so the buttons still works otherwise.

Touch Sensors

Touch Sensor

Behind the front panel are two Phidget  touch sensors based on the QT110 chip. These sensors works by detecting small variations in capacitiance caused by something like a human finger. They work through any dielectric material (in this case plastic) and don’t require actual touch, only proximity of about 1/4 inch. With the light off on Vender their presence behind the plastic isn’t noticeable.

BuyUsBeer.com

Vender in Buy Us Beer mode

My roommates (Tom and Jonathan) put together a website and hooked Vender up the general internet at http://buyusbeer.com . Here we stream a live video of our living room and the machine. You can pay $1, see a countdown before the beer comes out, and then watch us drink it. We’re operating it on friday nights and its been surprisingly popular among our friends as well as the reddit community. We don’t really make any money off it, especially considering paypal takes 30cent from every dollar, but we’ve sold a surprising amount of beer.

Finally…

Me and all my roommates are moving out in a few weeks, so we’re putting the vending machine, electronics, and buyusbeer.com website/domain on ebay. %10 of the sale is going to Kiva. If you’re curious, check out the sale at eBay.

If you have any questions, feel free to get in touch at chris@varenhor.st. You can also find me on twitter @varenc

From a search like this I can harvest thousands of reliable emails off linkedin.com, or the general internet, using only the search engine context.  In fact, I did, here’s 500 gmail addresses from LinkedIn with the last few letters removed.

Search engines don’t index special characters, so an email of the form “email@domain.com” is protected from this sort of discovery.  The basic trouble is “email AT domain DOT com” is completely indexed by search engines, and its unique enough that whenever you see “at domain dot com”, you know its part of an email address.

If you really want to evade an email harvester, put up an image of your address, use some css/js obfuscation techniques, or encode your email in a simple statement like ‘my last name at gmail.com’

Personally, I already get enough spam, and gmail provides excellent enough spam filters, that I don’t mind spreading my real email address around anyway.  Go ahead, send me a note at chris@varenhor.st if you wish!

@varenc

Code

There’s an app for that.

Here’s the story of iDoor, the iPhone controlled hydraulic dorm room door.  Enjoy. Credits to Greg Schroll for most of the hardware.

Life at MIT can be tough. With all the problem sets, and projects taking up time, when I come back to my dorm room to crash, I don’t want to waste time opening doors myself! That’s why my room is outfitted with an iPhone controlled hydraulic door opener and unlocker.  Just tap the “iDoor” app on my phone’s home screen, and the door opens for me.  Its 2009 after all, about time we stopped carrying around shaped bits of metal to open up locked doors.

Chris Varenhort's iPhone has one special app...

When security isn’t my chief concern, I can even ditch the phone altogether and just give iDoor a ’secret’ knock (not so secret any more) and let the vibration sensor trigger the door opening.  See the video above for the full run through.

Technical Overview

Phidget control board

iDoor is controlled directly from a scrounged up PIII computer running Ubuntu, interfaced with the hardware using the wonderful Phidget 8/8/8 control board.   An early version of the controls used an MIT Happyboard, but for Internet connectivity and development speed, the full PC was chosen.  The software was written in Java using the Phidget library.  (I’ll share the code if you’re interested).

Solenoid valves

Piston

The door is opened by a hydraulic actuator that taps into the sink in the room.   It was built by Greg Schroll in 2006.  The sink inflow tap and outflow tap are connected to a set of 4 one-way solenoid valves.  These valves are connected in such a way that together they can function as a 3-way valve.  Either pushing water one way in the chamber, forcing the piston to open the door, pushing it the other way, forcing the piston to close the door, or diverting water directly from the sink tap to the sink drain (just wasting water!).  The door actuator was custom built by Greg, so get it touch with him if you have questions about its construction.

Relays controlling the solenoids

There are two relays between two pairs of solenoids and the 24v power supply.  The relays are tripped from the control board.  One relay opens the door, the other closes it.

Door handle actuator

To ‘unlock’ iDoor, a Phidget servo controller has a large Hitech HS-755 servo twist the handle. While opening, it just twists the handle all the way, and when closing, the pulse width is enough to keep the deadlatch from applying too much friction to the strike plate, but still lock. The servo controller can’t output enough power to turn the big servo, so I spliced in a 1.5A 5v cell phone power supply.

Limit switches

There are two limit switches on the door that depress when the door is in its fully closed or fully open state.  The software uses these to know when to close the solenoids.

Interfaces

There’s a re-appropriated handicap button(seen in video) that also ties into the Phidget control board for easy opening when I’m away from my computer or without my phone.  It also functions as an emergency stop button to stop the door while it’s moving.

Vibration sensor

For knock activation, there is a vibration sensor at the top of the door positioned so that when the door is closed the sensor part touches the doorframe.  The control software uses the analog input from this sensor to detect my secret knock pattern, and open the door.

I also had my laptop configured so a particular key combination would alternate the door’s state.

A nice property of the whole design is that it can be completely removed from the room without too much work (though who would want too?).

Thoughts of living with it for 9 months…

I spent my senior year living with this door, and besides having to replace a servo, it pretty much worked flawlessy.  The only trouble was my hallmates hacking the door, and random EM noises doing weird things to it. I’m not sure if I’ve actually saved time in the long run, but it was definitely fun. Some of my favorite uses of the door are opening it remotely for friends that need to get stuff out of my room, (though it can be confusing for people that aren’t familiar with it).  If I leave in a hurry, I can also just tell my phone to close my door when I remember later.  Another good trick is opening and closing the door randomly during parties on my hall, confusing bystanders endlessly.

Some things I’ve discovered:

• When I turn on my speakers, my door handle twitches.
• Once I left a long analog input cable going into the control board, and it would somehow pick up noise in just the right pattern to trigger the opening sequence.  This always happens at about 4am while I am sleeping.
• A secret knock, isn’t actually that secure.
• Handicap buttons aren’t as hard to find as you think
• Even after 9 months, it never gets old.

5. As your final hour approaches, you bequeath your belongings to charity and those around you.
4. You spend your last days surrounded by friends and family.
3. You’ve been in pain for so long already, that in the end, you’re happy to go.
2. There’s an elaborate ceremony with inspirational messages to mark your passage.
1. You know you’re going to a better place.

For 2009, I’m going to fill this up with more interesting content then this.

apparently its wireless, and pretty darn simple at that. Such a small board, and a 9v battery. I think I’ll turn the button into a button to operate my own door, and then use the board to make myself my own wireless automatic door opener.

open(INPUT,”FILE”);

#for file slurping
undef $/;
$line = <INPUT>;

#get ride of empty lines
$line =~ s/\n\n/\n/g;

#make the numbers pretty
$line =~ s/([0-9]){0,1}[\-\.\)\( ]([0-9])/$1$2/g;
$line =~ s/([0-9]){0,1}[\-\.\)\( ]([0-9])/$1$2/g;

#we only want mobile numbers (ending in M)
$line =~ s/([0-9])M\n/$1\n/g;
$line =~ s/\n([0-9])+[A-Za-z]\n/\n/g;

#get ride of the letter headings
$line =~ s/\n[A-Z]\n/\n/g;
$line =~ s/\n[A-Z]\n/\n/g;
$line =~ s/\n[A-Z]\n/\n/g;

#Comma delimitation!

$line =~ s/\n(.+[a-zA-Z])\n([0-9]{1,})/\n$1,$2/g;
$line =~ s/\n(.+[a-zA-Z].+)\n([0-9]{1,})/\n$1,$2/g;

print “$line”;