On November 23, 2013, Eugene Maker Space held its first ever punkin' chunkin' competition at The Science Factory! It was such a fun event with a fantastic turn out. We had five teams enter the pumpkin chunking contest, with a 6th last minute entry. The last entry was a much smaller machine that threw apples instead of pumpkins. This machine was measured but competed in it's own "apple class". It was much smaller than the other chunkers but it was no less impressive, as the results will surely demonstrate. All of the teams put a lot of effort into their machines and it was fantastic to see the different types of machines. There were three trebuchets, a mangonel, and a three armed slingshot. They all performed fantastically.
The competition had three heats. Each team got to fire their chunkers one time per heat. The furthest distance out of all three heats was the one that was counted for the contest results.
- Team Low Earth Orbit - 380 Feet
- Team Shanker Free Crankers - 233 Feet
- Team F=MA - 74 Feet
- Team Kerbalnauts - 70 Feet
- Team C-Pepo Propulsion - 57 Feet
- Team Waffles - 376 Feet
Thank you so much to all the teams! Without you this would not have been so much fun. Another thank you to The Science Factory for hosting the event. And yet another thank you to everyone that volunteered to help out with the event. It wouldn't have gone as smoothly without you.
For more photos, check out the following links!
Eugene Maker Space will be holding it's first ever Punkin Chunkin' contest! If you aren't familiar with the tradition of punkin chunkin' then you are in for a treat. The general idea is for teams to build contraptions that can launch pumpkins as far as possible. Whichever team can launch their pumpkins the farthest will reign as champions! A simple Google search for "punkin chunkin" will bring up plenty of information and videos of other contests and designs.
Since we will be holding this event at the Science Factory, and we want to make sure it's as safe as possible, we will be launching small pumpkins only. These are pumpkins weighing between 1.5lbs and 2lbs. This will help keep the contraption size and energy down to a minimum and hopefully prevent any dangerous mishaps.
Where: The Science Factory front yard
Day: Saturday, November 23rd
Time: 11:00am to 4:00pm (or whenever we are finished!)
You can see the launch zone in the below picture. Contestants will launch from the blue firing line aiming down range to the east. The first red box is the primary launch zone. "The Great Beyond" is further down range and will remain clear in case any contestants are capable of building launchers that can actually chunk that far.
How to enter
You do not have to be a member of Eugene Maker Space to compete. Everyone is allowed to participate! If you would like to sign up to compete, please email email@example.com with your team name and the names of your team members.
Now for the official EMS Punkin Chunkin' rules!
- No compressed air/compressed gas devices
- No explosives.
- Teams must release all energy from their launchers until it is their turn.
- You may sign up as an individual or as a team.
- Machine must not cross the firing line.
- Machines must be ready to fire within 3 minutes.
- Each team will get three launches.
- If a team loses a pumpkin after launch they may get an one extra try if the team has a backup pumpkin ready to go.
- Pumpkins must weigh between 1.5lbs and 2lbs.
- Teams provide their own pumpkins.
- Pumpkins must remain intact until they hit the ground.
- Pumpkins cannot be modified (except for painting).
- Teams may paint their pumpkins for decoration.
How to win
To win the competition you just need to chunk your punkin farther than the other teams. That's it! There will be three heats. Whichever team gets the furthest launched pumpkin out of all three heats will be declared the champions.
Our official entry video:
A second version that includes a voice over with more detailed explainations:
Somewhere around June 14th, Eugene Maker Space formed a seven member team to compete in this year's Red Bull Creation Challenge. We submitted our entry form and eagerly waited to see if we were accepted. On June 20th, we received our Bullduino in the mail, and on June 21st we had our first meeting to plan out our creation. It was a long two weeks in which everyone put in their all. Most of us spent almost all of our free time for two weeks working on our creation, much to the chagrin of our loved ones at home. Finally, on June 3rd at 11:50PM Pacific Time, we uploaded our video entry for the contest. A mere 10 minutes before the deadline. Will we become one of the 12 finalists? It's hard to tell at this point but we will find out on July 9th. Until then, we wanted to publish some information about how our creation actually works. So much went into the design and building of this creation that it was impossible to put it in all in a two minute video (two minutes was the requirement from Red Bull). So without further delay, let's go through the build process.
Seven members of Eugene Maker Space formed the team for this years challenge. Those members are:
We all have different backgrounds and areas of expertise, and we all have the desire to work together and learn new things. We formed a fantastic team to take on this challenge.
It all started on our EMS Discussion email list. Seven interested members started brainstorming ideas for our creation once we had submitted our application. The one idea that seemed to resonate with everyone was a refrigerator stocked with Red Bull that would automatically present the user with a fresh Red Bull by opening an iris mechanism on top and slowly lifting it up through the iris.
Once we received our Bullduino in the mail, we held our first meeting to talk about this idea and figure out how exactly we were going to build it and what other features we wanted it to have. We held a whiteboard session to figure out what features we wanted our fridge to have. We placed the ideas on a Cartesian plane to compare their difficulty related to their "coolness" factor. The idea was to figure out which ideas would be easy to implement but really cool so we could concentrate on those, while ignoring the extremely difficult ideas that didn't add much to the "coolness" factor. Some of the ideas from the white board session didn't end up making it into the final design due to either time constraints or the idea just not panning out as desired.
Once we had some direction, different members seemed to gravitate towards different pieces of the puzzle. This worked out well because we could solve different problems simultaneously to save some time. Having a member "champion" a certain mechanism meant that no piece was neglected but we were still collaborating and working together every step of the way to solve these complicated problems. Here is a simple list of all of the features we wanted our creation to have.
- Cold Red Bulls
- Iris mechanism on top
- Pneumatic can raiser
- Ability to hold multiple cans of Red Bull and automatically dispense them
- Fog blast as the Red Bull can is presented through the iris
- Reject empty cans that are not Red Bull cans
- Accept empty Red Bull cans and store them inside
- Flying sparks at some point (a device was constructed but not implemented in the final design)
- Appearance of an alien object from outer space
Since we knew that we wanted our drinks to be served cold, we knew we had to start with a refrigerator. Luckily, just a few days before the contest started, someone happened to drop off a mini-fridge at the shop. We already had two mini fridges so this third one was a perfect candidate to be torn apart for the project. Immediately after our white boarding session we started tearing the fridge apart to figure out how we might be able to fit everything.
We tried to remove the small freezer box but we realized that it was actually plumbed into the refrigeration line directly. Not wanting to leak Freon everywhere and potentially cause ourselves a lot of extra work, we ultimately decided to leave the freezer box inside the fridge. At one point, we accidentally shorted out the thermostat against the metal freezer box, resulting in a large spark and some scorch marks.
We ended up completely removing the refrigerator door to make room for more components. In order to fit everything into the fridge, we had to lay the fridge on its back side with the door facing up. After we had gone down this road we realized that putting the fridge on its back was actually probably bad for its operation. Due to this, we didn't end up turning on the fridge in its final operation.
We knew we wanted to put cans into the creation. But how was the creation supposed to know when we wanted to put a can in? The iris had to know when to open up to accept a can. We could have used a button or switch but that's not very alien-like. An alien device would just KNOW when to open as if by magic. To simulate this, we used an ultrasonic PING sensor. This sensor is hidden inside of one of the side pillars on top. It faces the iris and detects when a can is placed above it. Once the can is detected, the iris opens and the platform raises up.
One of the first things we decided on was that we wanted the Red Bull to be dispensed through an iris mechanism. How were we going to build this iris mechanism? Ben had previously made an iris mechanism out of MDF.
We used that same basic design to make a smaller mechanism that would fit a regular sized soda can. Michelle used her amazing scroll saw skills to cut out a new iris mechanism out of wood using a paper template.
After the iris was cut out and tweaked to work smoothly, it was painted black and coated with varnish. We attached a stepper motor to it and wrote up some code to open and close it.
Eventually, we mounted it to the underside of the creation's top cover. It was mounted with copious amounts of hot glue since hot glue is quick and strong enough.
Once the iris was built, we needed a way to drive it. We decided to use a stepper motor since stepper motors allow for a very high degree of control and accuracy. We were able to determine the correct number of steps to fully open and close the iris. The Bullduino communicates with a stepper motor control board, and that control board drives the stepper motor with the correct amount of power.
Pneumatic Can Raiser
Once we had the iris figured out, we still needed a way to lift a Red Bull can up through the iris. Ben had an idea to use a pneumatic piston mechanism. The basic idea was to use an air compressor to fill a tank with compressed air. Then we would have one valve that would release air slowly into a piston to raise a can of Red Bull nice and slow. We were going to a have a second valve that would quick release the air so we could shoot the piston up at high speed for the fast ejection of non-Red Bull cans. Then, a third valve would release air from the system so the piston could lower back down from the force of Gravity. We ended up only needing two valves however. One to pump air into the piston, and one to release it.
The piston mechanism was one of the trickiest parts of this build. We tried several piston designs, starting with a DIY piston made from PVC pipe.
This did work to a degree, but not reliably. We had a really hard time creating an air tight seal between the piston and the piston chamber. This was really important because the piston had to be able to lift up the weight of a soda can, and we needed a certain degree of control over the piston so the air pressure in the chamber didn't get dangerously high. We tried creating a good seal by making gaskets out of duct tape, electrical tape, teflon tape, weather stripping, and other materials. Unfortunately nothing worked well enough to make a good piston from PVC.
We ended up using a bicycle pump as a piston. This worked really well because a bicycle pump is essentially already a piston with a mostly air tight seal. If you hook up an air compressor to the output line of the bike pump, air fills the chamber underneath the gasket and the handle of the bike pump will raise up. This is assuming there is not a one-way valve in the bottom of the pump. Ben found an old bicycle pump at Bring Recycling for a few dollars that worked well for our purposes.
The bike pump did end up working but it needed some tweaking. First, the output valve on the bike pump was too small. We couldn't get air in there fast enough to eject a soda can at high speed. We ended up having to drill the hole out bigger. We purchased a tap and die set from Harbor Freight to tap the new hole, but the set didn't end up having the proper tap for our needs. With time racing against us, we decided to just thread the pipe fitting into the bike pump and epoxy the hell out of it. This ended up working perfectly. Second, we had to epoxy on a piece of wood to prevent the pump handle from going all the way down. If the pump handle goes all the way down, it prevents air from getting into it and the piston just doesn't work.
We also ended up unscrewing the top of the pump and replacing it with a piece of plastic pipe and an end cap with a hole in it. This helped to make sure the piston raised straight up. Without this in place, the piston would have some room to move in different directions, making it difficult to get it to fit right into the iris.
Another requirement we had for this project was to ensure that we could dispense multiple cans of Red Bull without having to reload the machine. We came up with several ideas for this. The first ideas involved using a rotating platter filled with Red Bulls. Another idea was to use a horizontal magazine. We ended up deciding on a simpler method though, using a vertical can magazine with a custom designed lever mechanism.
Here is a short clip that shows the loader in action.
The problem with the can magazine, was that it drops the Red Bull cans a good 14 inches or so lower than the platform. It also drops them in a horizontal position. We needed a way to get the Red Bull cans back up onto the pneumatic riser platform and in a vertical position. That's where the can lifter mechanism came in. We were able to build this mechanism using some parts from Kassie's DLP 3d Printer project. This mechanism actually serves several functions. To explain them, we will walk through the lifter's duties as they would happen in normal operation.
The lifter starts out in a "staging" position with one Red Bull can already loaded into it. The staging position is just below the pneumatic platform. The reason for this, is that it takes the lifter a good minute to go all the way down, grab a can, and then all the way back up. Having one can already loaded up means that you can get your Red Bull fix much quicker.
Once the machine has recognized that an empty Red Bull can was deposited, the lifter raises up slowly above the pneumatic riser. As it goes up, a piece of fishing line pulls on the side closest to the pneumatic platform. The lifter is on a hinge, so the fishing line causes the lifter to swing up like a dump truck and dump the can onto the platform in the vertical position.
Once the full Red Bull has been delivered to the user, the lifter lowers all the way to the bottom of the can magazine. Down there, it physically presses against the can loader mechanism to release a single can into the lifter. Using the can lifter to actuate the can release mechanism meant that we could do without one more servo or electronic actuator and cut down on the complexity of the electronics. Here is a video clip that shows how the can lifter actuates the can release mechanism.
Finally, the lifter mechanism brings the full Red Bull can back up into the staging position, waiting for another empty Red Bull to be deposited. Below is the relevant part of our entry video that shows how the can lifter dumps the can onto the platform.
Another idea we really wanted to implement was to have a blast of cold fog spray against the Red Bull can as it majestically rises from the iris. We thought of a few ways to accomplish this task, including using CO2. We ended up instead using those duster cans you can buy from any computer store. If you hold the cans upside down and spray them, you get a cold burst of liquid that comes out in a white mist. We knew this would be the perfect effect for our fog blaster. But how would we control the blast with the Bullduino?
We ended up designing two custom parts to be printed on our Makerbot Thing-o-matic 3D printer. The first part was a replacement nozzle. The original nozzle was nice, but it only allowed you to spray the fog in one direction and it didn't allow us to hook it up to any type of hose. We wanted to be able to attach a hose to the nozzle so we could direct the fog blast towards the can easily.
We used Google Sketchup to design a replacement nozzle that would fit over the small tab on top of the can. The nozzle also had a hole on top the exact right size a 1/4" vinyl tubing. This allowed us to just press the tubing into the adapter and spray a blast of cold fog wherever we wanted!
Once the nozzle was printed, we stuck it onto the canned air and attached the vinyl tubing. We routed the vinyl tubing around a piece of coro-plast in a circle, plugged the end, and drilled three holes into it. The holes were to direct the spray at the can. Here is a video of some initial tests:
The next step was to figure out how to control the fog blast with the Bullduino. Our first thought was to use a servo to somehow pull down on the nozzle lever. We initially held the servo onto the can using rubber bands.
This proved that the idea could work, but it wasn't very strong. We ended up designing a second custom part in Google Sketchup to hold the servo onto the can securely.
The part needed a bit of post work with the sander but eventually it was a snug fit and it works perfectly! This video shows how the fog blaster works in more detail.
These custom parts make it a piece of cake to switch out to a new duster can. You just pop off the top and bottom and switch to a new can.
We knew that we wanted to eject non Red Bull cans from the system, but keep actual Red Bull cans. This meant that we needed a way to identify one can from another on the Bullduino. Our first thought was to use a barcode scanner. When a local electronics shop went out of business, James managed to pick up a several hundred dollar laser barcode scanner for a measly $5. We had to use this in our project. The barcode scanner had a serial output with a DB9 connector so we knew it should be possible to get the Bullduino to talk to it. After many days of fighting with the different serial voltage levels, Weston came to the rescue and provided us with a simple two diode circuit to convert the barcode scanners RS232 voltage levels to the Bullduino's TTL voltage levels. We finally had some one way communication happening. Once we had that working, we just scanned the Red Bull's barcode and hard coded it into the Bullduino code. Now if any other barcode was scanned (or no bar code at all) we knew that it was not a Red Bull can.
The other problem with using a barcode scanner is that the can has to be in the proper orientation in order for the laser to actually see the barcode on the can. To overcome this problem, we used a servo motor, a few gears, and a 3D printed Lovejoy couple. The servo interacts with the Lovejoy couple using the gears so it can spin the couple. If the can platform is down, the other side of the Lovejoy couple locks into place allowing the servo to rotate the platform with the can on it. We configured the servo to rotate the platform three or four times to give the barcode scanner a few chances to read the barcode. The beauty of the Lovejoy couple is that it permits the servo to rotate the platform, but it also still allows the platform to freely rise up and fall back down. Here is a relevant portion of our entry video that shows this functionality:
The barcode scanner itself is mounted to a custom 3D printed bracket. The bracket is then mounted near the pneumatic platform so it can easily scan the Red Bull's barcode.
Empty Red Bull Acceptor
We knew that we wanted to be able to accept empty Red Bull cans. The idea here was that if you inserted an empty Red Bull, it would replace it with a full one as if by magic, leaving you wondering what actually happened to the original. To accomplish this task, we used a type of motorized linear actuator. If you apply 12 volts to the motor in one orientation, it shoots a small piston outward. If you apply 12 volts in the other direction it will retract the piston. To simplify things, we placed an elastic band around the piston so that it would automatically retract unless 12V DC was applied to the motor.
We mounted the actuator to the black cup around the platform so it could easily kick off an empty Red Bull can. We even had room inside the mini fridge for a small recycle bin that can hold approximately ten empty cans of Red Bull. The actuator kicks the cans into this bin to make room for the full Red Bull can.
With all of these different mechanisms in place, the electronics became very complicated. In fact, at one point we had managed to use almost every single pin the Bullduino had to offer. The Bullduino controls pretty much everything that our creation does. As such, we decided to display it prominently on top of the creation.
We soldered a 25 pin ribbon cable to a prototyping shield so we could easily interface to every one of the Bullduino pins that we needed.
That ribbon cable then goes to a breadboard down inside of the machine.
All of the servos and other interfaces plug into this breadboard. We would have made our own PCB but there was not enough time for us to design one and etch it, especially since things were changing constantly so we would have ended up having to design and etch multiple PCB's throughout the process.
The two stepper motors (one for the iris, one for the can lifter) have their own stepper motor controller boards. These boards provide an extra 12V of power so they can do their jobs. The Bullduino talks to each controller using a "step" and "direction" pin.
The sprinkler valve and air release valve for the pneumatic system require 24V of power in order to function properly. For this, we used a 24V wall-wart adapter we found and we power the valves using a relay board. The Bullduino can send 5V of electricity to the relay, and the relay will switch 24V back to the valves.
The can kicker actuator and the air compressors (we hooked two small compressors up together for MORE POWER!) require 12V power. For this, we used a 12V, 6amp power inverter and two more relays.
All together our creation uses four relays. We have installed 6 relays in case we want to add more features later. The Bullduino didn't put out enough current from it's pins to drive the relays directly. Instead, we had to create a custom board that used transistors to direct a higher current 5V source to the relays. This worked like a charm.
The DB9 connector for the barcode scanner plugs right into the breadboard and is held on (barely) with double sided foam tape. The ping sensor also plugs into the bread board.
We used a 5V 2amp switching wall-wart power supply to power the Bullduino through the breadboard. The electrical supply runs through the ribbon cable up to the Bullduino's VCC and GND pins. This allows us to power it without an extra cable running up on top of the machine.
At one point, we had programmed in an interrupt routine to animate (fade in and out) some EL-wire on the outside of the machine. We had to build a custom circuit in order to get this functionality and unfortunately we had some problems with it and did not have enough time at the end of the build to fix it. It was worth mentioning though as a lot of work went into coding the lighting animation, and if we had an extra day we would have had it working.
A good portion of time was spent trying to build a device that could shoot sparks several feet. We thought it would up the cool factor of our creation. Many tests were run and eventually a device was built that used a small rotary tool with a grinding wheel pressed against a flint. When the rotary tool was turned on, it rubbed against the flint creating sparks.
Unfortunately, it could only throw sparks about two or three inches. We had planned on incorporating this into our design, but we ran out of time at the end and did not get to add it in.
External Case and Frame
We knew from the beginning that we wanted our creation to look like an alien device that landed on our planet. We drew inspiration from Warhammer 40k for the basic design, and from Star Wars for the exterior paneling.
First, a wooden frame was constructed to fit snugly around the mini fridge. This frame allowed us to attach caster wheels to the bottom of the creation and it provided us with a solid foundation on which to build the outside aesthetics.
The outside portion that gives the frame it's alien shape is made from foam. It was carved out using a variety of tools such as a sawzawl, hot wire cutter, and foam knife.
Once the frame was built up, it was time to prime it for paint.
The frame was painted black and then had a mixture of green paint and polyurethane applied over top. This mixture gave it an oozing green look that really made it seem alien.
Some stonehenge for the top and an eye made of wire for the Bullduino.
Some panels were cut out of coro-plast to give the outside frame some definition. These were painted similarly to the outside frame, but with a purple mixture instead of green.
After the panels were glued on, some EL-wire was glued around the edges of the panels. This would really make our creation stand out in the dark. There are four EL-wire strands, each powered with a separate inverter running from two AA batteries.
One thing you can't see in the photos is that a large white LED light was placed inside of the front pillar. This was designed to illuminate the Bullduino in the eye piece. What we didn't expect was that we would accidentally create a Bull Signal!
This project was incredibly challenging and incredibly fun. Everyone put in a ton of work and I heard multiple people say that this was the most complicated project they had ever worked on. We are all simultaneously hoping that we are chosen to move on to the final round of the challenge, and also terrified to move on because we will have to up our game even more.
A special thanks goes out to our family and friends who put up with us spending long days and nights at the shop to get this project done. Their support is greatly appreciated.
We spent the last two weeks building an entry for the Red Bull Challenge that we got submitted 10 minutes before the hard deadline last night. It was a race to the finish to get everything integrated, but we freakin' did it!
It's an Arduino (or in this case, 'Bullduino') controlled box of mysteries and delights with conditional logic and EL wire. Built into a mini refrigerator that was donated to the group, it uses sonar to sense anything approaching an iris at the top (which it then opens) so a pneumatic platform can raise up to receive the can. If you place an empty Red Bull can on it, it drops down into the box, the iris closes, and a barcode scanner tells the processor what the UPC is. If it's a Red Bull can, a solenoid kicks the empty into a recycling hopper and a stepper-motor loading mechanism rotates and drops a fresh cold can into its place.
The pneumatic piston smoothly lifts up through the once-again opened iris amidst a blast of freezing gasses and an ice-encrusted can is ready to be consumed.
If you place a non-Red Bull in the slot, the barcode scanner lets the processor know. Valves close and a pair of air compressors run, building up a charge, then the iris is flung open and the offending can is violently blasted out from inside the box.
It was a blast to build this over the last couple weeks and our team really came together! Great work, everyone!
Seven members from Eugene Maker Space have formed a team to compete in this year's Red Bull Creation Challenge. The team received a custom Arduino board from Red Bull last Wednesday called a Bullduino. The current challenge is to build anything using this Bullduino board. The team has come up with a pretty involved project and has been working almost round the clock at the EMS shop to get it done in time. The project has to be completed, filmed, and uploaded by July 3rd, so there is less than one week left.
After July 3, a team of industry experts will judge all of the entries and choose 12 teams to move on to the final round. In the final round, the teams will be provided with a theme. Each team will have 72 hours to build something around that common theme. The entire 72 hour event will be streamed live on the Internet. The winner of that contest will receive $10,000 in tool prizes.
Wish our Eugene Maker Space team luck in the competition and keep an eye out here for updates. They are keeping the project under wraps during the development phase, but once the deadline has been reached we will upload a video and some more detailed explanations so stay tuned!