bike alarm system


10 kW
May 25, 2006
i have been looking around for awhile for an alarm system for my bike
that would activate a pager. i believe the only way to protect my bike
is to come running when the alarm goes off. recent utube videos showing
blatant staged ripoffs of bikes from public places using saws and bolt
cutters reinforce my belief that an alarm is useless unless it alerts
you and you come running. Somebody suggested one from JC Whitney awhile ago, and i looked at it, but it did not really look like what i need,
and the only review of it was very negative. I did find one that is
exactly right for my needs and might be suitable for others as well. I
really wanted both a pager and an active non-contact proximity detector,
and I found exactly what i was looking for at only $69!

the Spy LM508 from West Coast Cycle is a 2-way pager alarm; you activate it with the pager and it sounds an alarm and alerts you when somebody messes with your bike. The pager works for 500 meters in the bike to pager direction and 150 in the pager to bike. you can remotely
activate/deactivate the bike power system and/or the alarm. there is a
locate button to set off the alarm from the pager. the system has remote
start and turn signal blinkers most of us will not use, but it has some
cool features the JC Whitney alarm does not. The most notable is a
microwave perimeter intrusion alarm. The control unit has a standard
shock/tilt sensor with adjustable sensitivity, but the selling point for
me was the microwave detector. The motion sensitive alarm covers an area about 1 x 2 meters, so when the antenna is properly located it should be able to protect the whole bike. The sensitivity of the microwave
detector is adjustable and i found it easy to adjust so it worked
without any false alarms and activated when i put my hand between the
seat and the handlebars or grabbed the bars or frame. The 125 dB siren
is quite small and easy to mount, and can be heard for a couple of
blocks. The system has great warning/retrigger modes, a pager-only
silent mode, and you can even shut down the power to the bike from the
pager as the thief tries to ride off, if you put in a power switching
relay. I intend to probably replace the siren with a speech synthesizer
chip that says "warning, alarm system activated, owner notified and en
route" for about another $20.

the unit retails for $129 but is on sale at for $99, the same price as the
much less capable J.C.Whitney unit. I got mine for $69 on Ebay. I had
considered building my own and just buying the pager part, but that was
$69 by itself, the same price as this complete system. West Coast Cycle
also makes a less expensive pager unit without microwave and a more
expensive unit without the pager or microwave. The LM508 is available
right now on ebay for $69 on buy it now and $12.74 shipping, and IMO is
the best alarm for an ebike available for anywhere near the price. I
cannot imagine needing any more power or features. It even does rolling
code hopping to avoid hackers!! It is of course made in China, but
appears to be fairly well put together and worth the price.

According to Wiki, 125db is a bit shy of the pain threshold, 134 db, but 120 is adequate to cause hearing loss even for short exposure. Kinda makes the 500m range pager seem redundant.

I remember seeing kids beating on a bike parked onto a fence, once. They kept beating it because it had an alarm, it amused them to set it off. Ponder.

What I'd like to see is boomerangs for bikes, it's a GPS tracking thing like in movies. Something like that compared to the above would be the ultimate, in my view.

EDIT: COMBINED with the above, would be ultimate...

The strategy I personally use consists of using a ratty bike and keeping it mostly out of sight.
That's a good deal.

A pager feature saved my car numerous times when I lived in NYC.

I would like to see a new feature tho...



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Oh, heh, like this?
Bzzzzzzap! That'll teach 'em.

I've seen some devices that are like a cell phone with a GPS. You can track the location of it from a website. Cheaper than a LoJack, but you have to pay for monthly service.
i'm not sure how much i will use the siren. it is painfully loud...i may just use the pager function. the pager tells you if it is a single tap or repeated movement, and differentiates between that and the microwave alarm, and i am usually close enough that i can just zip out and take a look.

i know there are cases where kids just set off alarms on purpose, but that does not seem to be too much of a problem with car alarms around here. i don't expect them to steal my new recumbent but i am concerned about $700 worth of batteries or other components disappearing, or something that is on the border of vandalism like my seat cushions, which are not expensive but would be a hassle to replace.

a couple of people have tried to convince me an alarm is a negative thing that will cause me more trouble than it is worth, but i just do not believe that. an alarm system was the only way i could keep a stereo in my car in san francisco, so at least it will make me feel more comfortable about leaving the bike once in awhile.

it seems every time i post about something i think is a good idea there is always at least one person in power-assist who will be totally negative about it and try to talk me out of it. i generally ignore these people.

The alarm is a good idea i think-- if not for the bike, you gotta protect those batteries! I got $500 invested in lithium. I want to hear reports on how well this alarm system works before I jump aboard.
They claim no photoshopping anywhere on the site...


Edit: ok, so it's not really an alarm, but holy cow...

I can see Fetcher going insane with glee trying to outdo these guys and accidentally starting a big California forest fire.
i made one already :p there 2 anidized studs near my seat near the crotch area lol :p and i hook up a HID ballest lol just strip back the wires and away u go u ever see 300v hit u in the crotch lmao :p i also got it hookes up to the hand grips to it hurts like a son of a b ill post the vid that gave me the idea