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Microcontroller based geocaches


wlmckinnon
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I'm looking to see if someone else has created geocaches, based on microcontrollers, that allow interaction between the geocacher and the cache. For those that don't known, a microcontroller is the small computer thing that controls most electronic devices. They're in everything - toasters, radios, GPS receivers, cars, TVs, etc.

 

I've seen references to a Arduino based reverse-geocache box that must be taked to a certain location before it will open, but that's not what I'm interested in. I'm looking for a real geocache container that stays in one spot but reacts in some way to the cacher finding it.

 

So far I've created two caches that are based on AVR microcontrollers. AVR is one of the big families of microcontrollers. PIC is another. Kind of like a hardware Apple vs. Microsoft.

 

GC2P3F5 Parkway Shire – The Light of Eärendil

This cache uses an accelerometer (the thing in a Wii remote that detects motion) to see if it's being moved. When it gets picked up, it lights up some bright LEDs that are in a plastic vial. It's hidden in a dark spot down in a rotten stump.

 

GC2ZK79 Parkway Shire - Are You Smarter Than an Orc

This is a two stage cache where the first stage has a small (20 characters by 4 characters) display and various buttons for picking options and answers. When a geocacher finds stage 1, there is a button to turn it on, it then gives a quiz based on the Lord of the Rings. If they get enough questions right, it then gives them the coordinates for the final stage.

 

I have ideas for a couple of others that I want to work on and am wondering if anyone else has seen or is working on caches like this.

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Check out the Reverse geocache. Made with an Arduino.

http://arduiniana.org/projects/the-reverse-geo-cache-puzzle/

 

I really like this reverse geocache. It's clever, has a nice set of features and is very well crafted (much nicer than mine). While it's a geocaching thing, it's not actually a geocache, and it couldn't be published as one at geocaching.com. It's more of a specialized GPS receiver. Thinking about it, it could be set up as a TB that geocachers could "discover" as the owner carries it around.

 

This does open up some possibilites that I hadn't considered. You could set up a microcontroller based TB that discovers could interact with to get some information. One idea that I have been considering would actually work well this way. It could be taken to events and accessed to get information about the physical location of an actual geocache.

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Sounds good to me. They would probably be a mystery/puzzle instead of traditional because of theway you have to open it.

My "Light" geocache I just listed as a traditional, because while you interact with it, there is no problem to solve.

 

My "Smarter than an Orc" cache I listed as a multi, but I had considered listing it as a puzzle because of the quiz. There isn't a selection for "Multi-puzzle", and I've seen other multis with a puzzle component listed as multis. Besides, I had already hidden some puzzle caches and hadn't hidden a multi.

 

If I do a TB based one, it would need to be listed as a puzzle.

Edited by wlmckinnon
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I really like this reverse geocache. It's clever, has a nice set of features and is very well crafted (much nicer than mine). While it's a geocaching thing, it's not actually a geocache, and it couldn't be published as one at geocaching.com. It's more of a specialized GPS receiver. Thinking about it, it could be set up as a TB that geocachers could "discover" as the owner carries it around.

 

This does open up some possibilites that I hadn't considered. You could set up a microcontroller based TB that discovers could interact with to get some information. One idea that I have been considering would actually work well this way. It could be taken to events and accessed to get information about the physical location of an actual geocache.

 

geocaching.com does allow reverse geocaches and there are 4 of then in British Columbia. Savant9 has listed 2 of them which are mine.

 

GC2NPQQ

GC274MK

 

I also have a hangman game puzzle cache based on an Arduino - the cacher finds the hangman game and if they beat the hangman the lcd displays the final coordinates.

GC2W9AG. I got the idea from this project

 

I have a public list of Arduino based geocaches here. Can I add yours to it?

 

Team K1W1

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Thanks to repliers.

 

"Team K1W1" added a pointer to a bookmark list he has that has 15 microcontroler based caches listed. One has been archived, but the others are still active.

 

Following the links in the Dragon Puzzle geocache (GC2131Y) leads to another geoache, Riddlers Revenge(GCX7BD), that is electronics related, but may be a complex wiring of switches and lights. It may not be microcontroller based but is still nice.

 

"John E Cache" mentioned a geocache that would light up as a beacon at night. I have found this video on YouTube

. I'm not sure if this is the one being refer to or not. The video and comments are in German, but it does seem to be refering to a geocache. I've tried contacting the poster of the video, but haven't had any luck yet.

 

I'm currently working on a multi-stage cache that I'm going to call the "Fellowship of the Cache", I've been basing mine around the Lord of the Rings. It will have a first stage, four separate second stages and a final. The first stage will be microcontroller based and will give out the coordinates for the second stages. Each second stage will have a clue giving a part of the coordinates of the final, so cachers will need to find all four second stages in order to find the final. Stage one will give out the coordinates for the second stages one at a time. After giving out one set of coordinates, it will wait some amount of time (probably six hours) before it will give the coordinates for the next second stage. Hopefully this means that a different geocacher will get the coordinates for the next stage. It will step through the four like this. The geocachers will be encourged to not post the coordinates in their logs, but to contact each other for the coordinates of each of the stage two caches.

 

Once I have this one released. I'm hoping to do a similar one based on RFID tags and reader.

 

The YouTube video has given me an idea for a nighttime event cache based on these kind of lights. Where I live there isn't a good place to locate something like this. We're in too suburban of an environment. But there is a large green belt area that closes at night. I might be able to get permission to place something like this for several nights and treat it as an event.

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Along similar lines, would a WiFi based Geocache be permitted?

 

I was thinking of broadcasting a clue to the final location using the BSID of a WiFi network. So it would be a combination of Wardriving and Geocaching. There would be no need to connect to the network.

It's absolutely permitted, and has been done. Heck, toss in your final coordinates as the SSID. Anything is possible.
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How do you handle battery life?

Depends upon the device, but letting one kick-start with a simple button push, add an inactivity timer in the firmware to disconnect from the power source, and you can avoid any power use at all with the user not present. The electronics are easy. If the processor doesn't have a timer (that's pretty rare anyway) a simple R-C that is periodically tickled by an output port could be used for the inactivity timer.
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How do you handle battery life?

Battery life is probably the big issue. I put my caches out as normal unattended caches and hope they will last for awhile before batteries need to be changed. My Light of Earendil cache is based on an accelerometer to detect that it's being moved. I put the microcontroller in idle and wake it two times a second using one of the internal timers. I'm not putting it to sleep because of limitations on using the timer. I'm drawing about 3 mA when it's in idle, I think about 10 or so when checking the accelerometer and about 50 or more when I'm lighting the LEDs. I have a timer that turns off the LEDs after 20 seconds and waits another 20 seconds before allowing them to be turned back on. This gives a 50% duty cycle for the LEDs. I figure that someone that finds it will turn it on several times but eventually get tired and let it go to sleep. I blink a "Resetting" LED turning the 20 second off time. There's no on-off switch, it just goes into it's base mode after 20 seconds of inactivity.

 

My Smarter than an Orc cache has a power on button. I didn't want to rely on having someone turn the switch off, so this controller goes into a deeper sleep waiting for an external interrupt from the power button. The deeper sleep means that the controller is drawing about 10 micro amps when its not doing anything. When it's on, it can draw over 100mA depending on how bright they have the display (I let them adjust the back light) and the number of status LEDs I have on. I again use a timer to control the on time. I have a 10 minute limit that could actually turn into 20 minutes. I allow 10 minutes while I'm presenting the instructions and then reset it to another 10 minutes when they actually start the quiz. They can choose to turn off the display after they take the quiz or retake it as many times as they want in the ten minutes. If they turn it off or the timer runs out, I give a message saying its going off for 10 minutes. The power interrupt is kept turned off for that ten minutes.

 

I've found it better to run the microcontroller at 3 volts and use 5 volts as needed for the accelerometers, LEDs and display. This means I use a boost circuit to get the 5 volts. I drive the boost circuit from a pin on the controller so that it's completely off when not needed.

 

So, on both, I rely on counters and a forced off time. I've tried to balance being generous with the on time verses the need to manage power.

 

I'm getting 1-1/2 to 3 months from my light cache off 2 AA batteries depending on how often it's turned on. I'm driving the Orc one off two C batteries and since I just put it out I don't know the real world life, but I'm expecting a longer period that from the AA batteries on the other even though I'm drawing more current when active.

 

I also use super bright LEDs but use current limiting resistors so they're not drawing their full current potential. This can give considerable saving during the on time.

 

It takes some playing using a multimeter to see what's happening, but you can get readings that will let you make rough calculations of expected life. I was hoping for 3 months for my lights cache based on this, but I'm getting less in the real world.

 

I've also seen some comments where people put spare batteries in their cache. My batteries are inside the cases that need screw drivers to open, so I haven't done this yet. I may try it on a futuer one.

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It's absolutely permitted, and has been done. Heck, toss in your final coordinates as the SSID. Anything is possible.

Do you know the GC codes or names for caches where this is being done?

Two of them that I know, one rather old and clearly identified, and one of my own, where the situation is intentionally obscured.

 

GCY884 in Loveland, CO

GC2G604 in Longmont, CO

 

I even fly the 'beacon' attribute on mine. It was designed for Chirp, but fits all three portions of that cache.

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I really like this reverse geocache. It's clever, has a nice set of features and is very well crafted (much nicer than mine). While it's a geocaching thing, it's not actually a geocache, and it couldn't be published as one at geocaching.com. It's more of a specialized GPS receiver. Thinking about it, it could be set up as a TB that geocachers could "discover" as the owner carries it around.

 

This does open up some possibilites that I hadn't considered. You could set up a microcontroller based TB that discovers could interact with to get some information. One idea that I have been considering would actually work well this way. It could be taken to events and accessed to get information about the physical location of an actual geocache.

 

geocaching.com does allow reverse geocaches and there are 4 of then in British Columbia. Savant9 has listed 2 of them which are mine.

 

GC2NPQQ

GC274MK

 

I also have a hangman game puzzle cache based on an Arduino - the cacher finds the hangman game and if they beat the hangman the lcd displays the final coordinates.

GC2W9AG. I got the idea from this project

 

I have a public list of Arduino based geocaches here. Can I add yours to it?

 

Team K1W1

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I have a project on the go. Circuit sorted and code sorted thanks to a good friend who is a coding wizard, prototype working sweet as a nut. Just need to design the circuit boards and fit it into a box. Need to do some tests on power consumption and battery life. Arduino is the future, so many possibilities. Can’t wait to get this cache live.:P

Edited by peteb303
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I've just released by latest microcontroller cache:

 

GC397W8 "Parkway Shire - The Return of the Rings"

 

It's Arduino based - Arduino Pro mini 328. It uses RFID tag reader, RTC, SD card, 4x20 LCD display, and capacitive touch keypad.

 

Cachers pick up an RFID tag and take it to the cach. Based on the tag's id, they are given one of four sequences of tasks to complete and codes to retrieve. The sequence and codes are different for the four types. Each tag gets a file on the SD card to track the activity for that tag.

 

This one uses all the pins on the Arduino and all memory. There is only about 200 bytes left. Both the RFID reader and touch pad use the UART input, so there is an external multiplexer chip to control which one is active.

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