Both EcoNic and myself have always been big MacGyver fans, so while thinking about new cache ideas MacGyver was a natural choice. We got excited about all the "MacGyverisms" we could get people to do, and could picture cachers trying to disarm a bomb with a swiss army knife and paperclip. Cool stuff we thought...

How we came up with the MacGyverisms:

A MacGyver cache idea is great until you have to actually come up with MacGyverisms that are interesting, a bit challenging but not too hard, foolproof, safe, can be hidden easily, fit into a story, and stick with the MacGyver theme of using science knowledge to fix stuff or get yourself out of a jam.

We went through the entire list of a thousand actual MacGyverisms from the TV series and movies, and we couldn't find a single thing that was suitable!

Right from the start we just HAD to have a bomb, not that we could call it that in todays climate, so it became a "self destructing waypoint decoder". What fun would a bomb be if there was no time limit to disarm it?, so we put a count down timer on it! We did some simple tests and figured that 5 minutes would be plenty of time. Oh, and we thought it would be fun to sucker you into thinking there was a disarm code, no way would it be that easy for MacGyver!
We liked the idea of planting the decoder under a bridge, to make you run from one end to another and back in a panic while the clock is ticking down...

We liked the idea in an early episode of sliding down a sand hill on a map to escape persuers, and we spent ages trying to integrate this into the story. The only sandhills around were too far south, so we tried for a grass hill instead and scoped out many locations towards the city. It was hard trying to find grassy hills steep and smooth enough to slide down on. We eventually found one or two, but then couldn't figure out how to adequately integrate it into the story. We even thought about getting the cachers to contruct a grass billy cart! We eventually had to scrap this idea entirely, too dangerous, the cache of "bits" would be too big, and not many people would "get" what was going on (why slide down a hill??)

Lets put the cache over there!

Next we had the brilliant idea that we'd hide the final cache on an island and get the cacher to construct a raft out of balloons and garbage bags! We spent ages on this too, and had it all lined up and the cache ready to plant. When we went out to try out the raft idea, it didn't work all that well (you'd certainly get wet), and we figured that people would not be happy getting their gear and clothes wet when they were not prepared for it. Also, winter, and the cold water, was coming on which made the whole idea fall flat. Scrap that, back to square one.

So with nothing left but an idea for a bomb and a bridge (and everyone waiting for us to plant this thing!), we searched around EcoDaves local area and found Nurragingy reserve. One visit convinced us we had a cachers playground right on our doorstep!
We found a very nice bridge for our bomb, and we found that each area of the gardens was themed with a different country, so we wrote this into the story. MacGyver would travel from country to country tracking down the Ming Dragon - cool!

The Ming Dragon story behind the cache is losely based on one of the MacGyver episodes.

It wouldn't have been a true MacGyver story if Murdoc (MacGyvers arch enemy) wasn't chasing MacGyver and Pete, so we integrated Murdoc into the story as well.

MacGyverism Solutions:

Ok, here is how we intended you to solve the MacGyverisms. But there is no "right" solution, as long as you solved the puzzle "on the spot" using whatever you had available, you have done a "MacGyverism". If ANY of the puzzles made you come back another time (especially with extra equipment), or you had to brute force the co-ords then you FAILED! :-P

The Level:

EcoNic showing the accuracy possible with the water level

You were supposed to measure the exact height difference of the top of the sign and the tip of the arm rest on the chair. The spirit level and string were in there as a decoy, they don't give you a very accurate solution.
The easy and most accurate solution is to fill the tubing with water from the waterfall (or wherever) and use the basic principle of water leveling to measure the difference. As long as you have no air bubbles in the tube and you hold it steady, the repeatability should be at least +/-1mm. So we set the waypoint increments to 5mm to give you plenty of margin. We got within 1mm every time we tried it.

We gave you 10 waypoints to choose from to discourage brute forcing, not that we figured it would stop some cachers! Many of the dummy waypoints were deliberately chosen at spots that would make you search for a while.

We orginally used a smaller diameter tube, but the friction on the inner walls of the tube caused a signifcant imbalance.

The Weights:

You were supposed to measure the exact weight of the "plastic explosive" (PlayDoh) using the smaller pencil erasers as a reference. The easiest way to do this is with a ruler (which you could get from the previous water level waypoint!) balanced on a fulcrum (stick, your finger etc). This forms a basic balance level. We deliberately picked the PlayDoh and Plastic Erasers because they would not slip off the ruler easily.

We wanted to hide this waypoint in something we could leave out in the open in an urban environment, just to throw you off. We settled for a Sprinker Control box (from Bunnings) and hid it part way into some bushes.

EcoDave planting the fake Sprinker Control Box.

The Bomb:

EcoDave constructing the waypoint decoder.

We wanted this to be an exciting and adrenaline pumping part to the cache, so we added a time limit and made you think there was a disarm code...
There was no disarm code of course, we wanted you to think under the pressure of a time limit (and possibly people watching) and figure out how to disarm a bomb that you have no idea about.

This is where you needed your swiss army knife to undo the screws on the box to get inside to the secret disarm switch. Push the disarm switch before the timer runs out and the final cache waypoint was displayed. Fail to hit the switch before the timer ran out would mean you had to wait another hour before it reset. The keypad was there as a decoy, only the "*" key was connected, so pushing the other buttons does nothing. We suspected a few people would try and think up some disarm codes and waste a lot of time pushing buttons to no avail.

For the technically inclined - the bomb uses a PIC16F628 microcontroller running on a 4MHz internal RC oscillator during operation, drawing 2mA. It automatically goes into a sleep mode which powers down the LCD and lowers the clock rate to 32KHz, drawing 50uA, so the batteries should last the shelf life.

We always wanted a bridge to hide the bomb under, and to make you run from one side to the other to disarm it. There just happened to be a nice one in Nurragingy Reserve.

The Fake Rock:

This is EcoNics handy work. We wanted to conceal the final cache into something inconspicuous, but it's a fairly sizeable cache box to hide. We got the idea of using a hollow rock to hide the cache in, but it proved too much trouble to hollow out a real rock. So EcoNic put her craft skills to use and made a fake rock out of concrete and chicken wire!
We thought about placing this in a very urban location, but after all the work making it we didn't want it vandalised or trodden on by kids or moved by a gardener.

It looks just like the real thing!

The Lock:

At the last minute we decided to add one final twist to the cache, put a padlock on it!.
But where to hide the key?
A standard cache waypoint containing the key seemed a bit boring, so we got the idea of hiding the key inside an object that was already in one of the other waypoints. We thought it was cool that you had the key in your hand and didn't even know it! The PlayDoh was the perfect way to hide the key, it's hard to detect it inside even when you try and dig it out.
We orginally had another "fake" dragon instead of the PlayDoh, but it was too hard to hide the key in it. The PlayDoh was simple and effective.

The waypoint decoder orginally had a clue about the key being in a "sticky situation", but the early cachers found this too easy. So we removed this hint for future cachers.

The Flood!

A once in 40 year flood hit the area a few weeks after the cache was placed. The water level in Eastern Creek (which flows under the bridge) rose well over the banks, over the walking track, and up over the garden where the waypoint decoder was hidden under the bridge. We used one of those airtight sealed cache containers, so the cache simply floated up and away, never to be seen again! The rock was also flooded, and needed some minor repairs. But being concrete it stayed put!

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Cacher Progress

SandyFeet:

SandyFeet took 3 attempts.

The Level:

Had trouble using the string balance technique, but got accuracy within the top 4 co-ords which was a good effort.

The Balance:

Used the water displacement method using the cache container and got it almost spot on. We didn't think of this one, we figured everyone would think of the balance level. A neat solution.

The Bomb:

Did not get it within the time limit.

The Rock:

Had little trouble finding the rock and figuring out the key with the extra clue "The key lies in Pete's sticky situation". We thought this made it too easy, so we raced out and erased the clue!, telling future cachers to simply "use your wits". Ain't we nasty!

BearLeft:

The Level:

Had trouble using the string level and water level techniques, but found WP2 after a bit of brute forcing.

The Balance:

Was out by 6g using the ruler balance, but with cache lids taped to each end of the ruler.

The Bomb:

Figured out how to disarm the bomb in a few minutes, an impressive feat! (not surprising though given BearLeft is an electronics geek like EcoDave!)
In true MacGyver style though they waited until there was only a few seconds left on the clock before pushing the disarm button!

The Rock:

Found the rock after a lot of searching and a clue. BearLeft had the "Sticky" clue as well, but they still tried to jimmy the hinge!
We have since replaced the chicken wire locked "door" on the rock with a chain and padlock around the cache container itself. This should reduce handling of the fragile fake rock.

Ideology:

 

Thanks for Playing!