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Forum Index : Microcontroller and PC projects : Tamper/movement Alarm ideas?
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lew247 Guru  Joined: 23/12/2015 Location: United KingdomPosts: 1702 |
When I put my weather station together, it's going on top of a 16ft scaffolding pole at the bottom of the garden. I want to put some kind of alarm on it, so if the station is removed from the pole the siren goes off. I know I can get the siren/alarm to trigger through an interrupt input on the Micromite (I hope) What I need is ideas on how to mount a trigger or what to use. The last one I had was a Maplin weather station and the outside unit got stolen by kids, and I don't want this happening to this one. I did think of putting a camera on it and taking a picture if it was moved, but I reckon a siren would be a better idea. The problem I have is how do I let the micromite know it's been moved? I thought of a mercury/tilt switch but if the wind blows too strongly it "might" set it off I also thought of using the ultrasonic thingy to measure the distance from the ground of the module and it it moves height by more than say 1M then get the siren to go off but I'm not sure how reasonable that is to actually do in practice Also how could I set it properly, as I'd have to have to put the unit on top of the pole and raise it in the air without it going off? Another idea I had was to use the gps receiver that's going to be in it using the altitude measurement Another idea was the pressure sensor - which "may" be the best I dont know When it's sampling the pressure, say get it to measure it once a minute amd if the pressure changes by more than a certain amount in less than a minute set the siren off or get it to convert to altitude and if the altitude changes by more than say 1 or 2M in a minute have it go off Thoughts? suggestions? ideas? |
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CircuitGizmos Guru Joined: 08/09/2011 Location: United StatesPosts: 1427 |
Is it a wired station? If wires get cut, and alarm goes off. Is it wireless? If communication is lost, alarm goes off. Micromites and Maximites! - Beginning Maximite |
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| lew247 Guru Joined: 23/12/2015 Location: United KingdomPosts: 1702 |
Wireless, but It won't be connected permanantly as it will be running on a battery, Although it will be solar charged I'm not sure how often to get it to send the data yet. Also It would be no use if I was away from the house, say at the shops, hospital on holiday etc, or probably even in bed, they'd have it gone before I could get out of bed. |
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Justplayin Guru Joined: 31/01/2014 Location: United StatesPosts: 327 |
How about a gyroscope tilt sensor. Set some predetermined allowable amount of tilt angle before a alarm condition is triggered. Or, a compass module so if the station is rotated too far the alarm is tripped. --Curtis I am not a Mad Scientist... It makes me happy inventing new ways to take over the world!! |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2934 |
You specifically say: '...if the station is removed from the pole the siren goes off...' Not knowing if you're setup is wireless/wired; and also not knowing where the MicroMite is (i.e. at the top of the 16ft pole, or indoors somewhere) then I can only suggest an idea that may need 'developing'. Place a magnet on the pole in a position that is 'touching' the station that you are trying to protect. Then simply have a reed switch in the station that will open/close when near/far from the magnet. In principle this is just the same as a magnetic door contact for a security system. This means lots of 'variations' in terms of physical size are readily available at low cost. Weather will not be an issue with this type of setup either; and also no awkward configuration. Can be made wireless too if needed. Don't dismiss CG's suggestions - the wired version being a variant of a 'tamper loop' in a security system. If you have a wireless setup, then you can build in a 'heart-beat' signal; and as CG says, if the 'heartbeat' is not seen, the trigger alarm. However, this means the alarm will only sound once the station has been stolen and taken beyond the RF detection range; this may be too late for an alarm! Hope there's something for you to think about in this post 
WW |
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| srnet Senior Member  Joined: 08/08/2014 Location: United KingdomPosts: 164 |
OK, I will ask the obvious question. Why, Who or What do you expect to climb a 16ft steel pole to nick your station ? I am assuming its unlikely that someone would bulldoze a cherry picker into you garden, just to tamper with your station. $50SAT is Silent but probably still working. For information on LoRa visit http://www.loratracker.uk/ |
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| lew247 Guru Joined: 23/12/2015 Location: United KingdomPosts: 1702 |
lol srnet The kids around here will climb anything - they got the previous weather station off the same pole. It's definitely going to be wireless, with a Micromite outdoors under the anenemoter and other sensors, and a micromite plus indoors. I actually like the magnet and reed switch idea WW, its simple and should work. I could have it so the switch is closed when the station is on the pole in the correct position, and if it moves it breaks contact with the reed switch simple and almost foolproof Thanks :) |
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TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6270 |
GPS wanders around on it's own so will not be very fast acting. Movement sensors will have to cater for wind induced movement. Ultrasonic distance will go off when the dog walks to the base of the pole. Magnetic switches look good. A sensor to detect climbing kids before they get to the top would be nice. Jim VK7JH MMedit |
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twofingers Guru Joined: 02/06/2014 Location: GermanyPosts: 1577 |
Hi I would prefer a gyroscope tilt sensor and/or magnet & reed relay. A big siren and a "High Voltage"-sign (fake).
This could be happen also with a gyroscope tilt sensor but you can set the trigger angle for 45° (even 90°) or more. Michael causality ≠correlation ≠coincidence |
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| robert.rozee Guru Joined: 31/12/2012 Location: New ZealandPosts: 2437 |
grease the pole? silicon grease would be a good option if you can get enough of it from somewhere, as it is really hard to clean off your skin. an electric fence generator has also been know to deter unwelcome intruders. cheers, rob :-) |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2934 |
Maybe get a longer pole  |
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| Justplayin Guru Joined: 31/01/2014 Location: United StatesPosts: 327 |
Perhaps add some grease near the top of the pole.  I am not a Mad Scientist... It makes me happy inventing new ways to take over the world!! |
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| MikeO Senior Member Joined: 11/09/2011 Location: AustraliaPosts: 275 |
Good Luck with you security measures! sounds like you have a few to choose from there, I liked the Grease and the Electric fence! While your musing over your installation, I don't know if you had considered it but you don't want to put your temperature sensors up that pole in full sun (oops, sorry your in the UK, I feel I can comment I was born there) seriously if you want accurate temp readings you need to put the sensor in something like a Stevenson shield, about 2 mtr (6ft) of the ground. This is mine, made from garden planter plates, painted reflective white. 
Mike Codenquilts |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6270 |
And the harder you make it, the more they see it as a challenge. VK7JH MMedit |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2934 |
I just realised I have your address; and I need a new weather station!! |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6270 |
Once you can get past the dogs, you will end up with the one that tried to be a lightning strike counter. It only counted one strike. Jim VK7JH MMedit |
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palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1989 |
These kids sound like little b******ds. I would go for an electric fence. Paul. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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| lew247 Guru Joined: 23/12/2015 Location: United KingdomPosts: 1702 |
LOL Thanks for making me smile this morning I love the electric fence idea - shame it's so illegal to have for this purpose or it would be ideal. Greasing the pole is a great idea I hadn't thought of, and along with the other ideas I'm pretty sure that once I get it all put together and get it on the pole, it will stay there till(if) I take it down. MikeO thanks for the advice about mounting and shielding the sensor  |
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| 5bar Newbie  Joined: 10/07/2014 Location: AustraliaPosts: 16 |
Greasy pole :D And a simple padlock I doubt the ferals are going to climb up with an angle grinder I can count to 31 on one hand |
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| circuit Senior Member Joined: 10/01/2016 Location: United KingdomPosts: 276 |
Pop down to your favourite paint store and buy some anti-climb paint. Note that you may have issues with your insurance company if one of the little xxxxs falls off your pole and suffers injury - in the UK we have hideous "duty of care" issues that require you to mark the premises with an appropriate warning notice etc. Many of our overseas friends may consider it bizarre, but if you place something that is "an object of attraction" into your garden that might attract trespassing "children" then you have further responsibilities to ensure their safety! Yes, folks, if they hurt themselves whilst they are trying to steal it then you can find a compensation claim landing on your doormat! Nevertheless, I think anti-climb paint is your best solution - it is revolting stuff to get on your hands and makes a pole or a drainpipe impossible to climb unless you come "tooled-up" with ways to overcome it. Have a look here: http://www.blackfriar.co.uk/product/anti-climb-paint/ |
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