Exclusively on this website, Charles Yarnold and Tom Scott explain the hard work behind the amazing Trendivend and Tresurebot machines featured in Episode 3 of Gadget Geeks.
Trendivend:
TOM: This was a big project for me. Direct-to-garment printing is a new technology, and hasn't yet evolved to the point where anyone, anywhere has built a T-shirt printing vending machine. I reckon that commercial versions of this are about five years away - and you'll start to see them in places like theme parks first.
TOM: At its heart, the printer was just a big inkjet, the same as you'd see on your desk at home. But plugged into it were special fabric inks and a load of software that hijacked its normal approach to make it work better on fabric. The trouble is that fabric wrinkles - so if it wasn't loaded properly by our customers, it would all go wrong.
CHARLES: My first choice on this build was, hack an existing machine, or build it all from scratch. After head scratching looking over the machine Colin brought into the barn, I thought it best to keep the fully working payment and vending system intact and design the rest of the system around it. Colin ripped out the top half of the vending shelves and made me a hatch on draw runners. When my controls detected that someone had bought and paid for a t-shirt it would activate a motor and open the hatch ready for the user to insert their t-shirt.
TOM: Now, I'll admit that the software for this was a bit of a bodge. Behind the scenes, I used Yahoo Pipes to speed up the headline-grabbing; it's an almost unknown but incredibly user-friendly tool, and includes a Term Extractor that pulled out just the most important phrases from all the sources we were scanning. The output from this got pulled into, of all things, a Google Chrome browser app that designed the t-shirts, and could throw out designs much faster than the printer could ever print them.
CHARLES: Once the user had finished inserting their t-shirt, they could select what category they wanted from the buttons at the top. The buttons were removed (by force, with a hammer) from a gambling machine. This gives them a lovely "clicky" feeling to use, and included a light inside! I sent that command to Tom to start his magic, then the system waited for the t-shirt to finish being printed and be removed. (This happened too quickly once, trapping the t-shirt inside... oops!)
TOM: I did have to put a filter on it. Some of the earlier t-shirt designs it came out with weren't exactly suitable for family viewing.
Ingredients:
1 x Vending machine
1 x Direct to garment printer
1 x Arduino
2 x Relays
2 x Electric windows motors
2 x Slide rails
2 x Netbook computers
12 x Buttons
50 x Blank t-shirts
Treasurebot:
CHARLES: The first step for me on this was reading the signals from a metal detector. I grabbed a nice £100 detector from the internets and cracked it open. Taking a feed from the speaker meant that I could read when the speaker was making noise, and so had found metal. Coupling this with 2 servos that pressed down on the cap of a spray can meant that I could easily spray the ground each time it found metal.
TOM: We borrowed £17,000-worth of high-accuracy GPS kit for the Treasurebot. It could plot finds on its treasure map down to two centimetres. This wasn't your average family sat-nav - it was military-spec equipment. Every time the metal detector fired, an onboard netbook saved the position and uploaded it, live over 3G, to a central server. A copy of Google Earth running on my own laptop then downloaded the data and drew the treasure map. Theoretically, we could have left Treasurebot alone in the field, and then come back with the map days later.
CHARLES: Next I needed to know we could leave the Treasurebot alone in a field, as we hoped to let it roam free without help from anyone. It needed to know what was around it so it could stop itself from running into a hedge or taking out a sheep in a nearby field! To do this I used the same system that you find in car parking sensors. With 4 mounted around the bot it could see where it was going and roam around the field without smashing into things. With this and the detector we have the electronics sorted for the bot.
TOM: It did get confused a few times - that's the shot of me shouting "what is this thing's problem?!" that you see in the show's trailer. I didn't know Charles had put it into what he called "Rambo Mode".
CHARLES: Colin did a great job of making the bot look less like a electric wheel chair and more like a bot, he upped the tires and encased the whole thing in metal and added a "get out of my way!" blue warning light to the top. He also added in extra big batteries to keep it going stronger for longer.
TOM: In the final test, what you see on screen is the conclusion of many, many hours spent in a windy, rainy, cold field in the Wirral. The little gazebo we'd brought got destroyed by gale-force winds at one point. It was not the easiest of days!
Ingredients:
1 x Electric wheelchair
1 x Metal detector
1 x Spray can actuator
1 x Netbook
1 x £17,000 gps system
2 x Arduinos
2 x Spades
4 x Sonar sensors
4 x 12v Batteries
