Does anyone know of a cheap light battery operated motion detector alarm? Thinking if the bad guys grabbed my bicycle it would scare them away. Motion detector, not light detector mode. more like the car alarm thing. Just thinking.
Thanks!

Louis LeTour? Red-read the OP and withdraw the question.

Alarm Bike Lock Bicycle Motorbike Moped Cycling Security Sound Loud Anti-theft | eBay

cheap one

and with remote

Remote Control Vibration Detector Alarm Security Car Bike Alarm System | eBay

One very low-tech option is to take a piece of line, and tie it to the bike. Run the line under your tent, then tie the other end to a tree or something. That way, if your bike is moved, the line under your tent wakes you up. Obviously, this only works when you're in the tent.

Unless you are camping a rather stupid location you shouldn't have to worry about anybody stealing your bike. I never lock my bike and haven't had any kind of trouble with anyone messing with it. Heck I camp in town all the time anymore, numerous times this summer right in the business district. Sorry forgot...some people want to tour on a million dollar bike. OOPS my mistake.

Robot Check

I have four of these and they work well enough. I wish they were of higher quality. But, they cost less than $5.

Joe

You can do it yourself. It's not that hard to do. I remember building one when i was in high school or was it before?
Anyway, here it is
DIY Motion Sensor Alarm System
Make Your Own Precise Vibration Sensors | Make:
https://www.learningaboutelectronics.com/Articles/Vibration-alarm-circuit.php

I never felt the need for one, but do have a caution about them. If you will be camping around other people, having an alarm go off every time a deer, turkey, or whatever wanders through camp would be pretty rude. Also in many cases parks pack cyclists in pretty close together and it would be tough to not have nuisance alarms when your closest neighbors get up during the night. If you do decide to use one please be careful and courteous with it.

Alright will reduce the loudness of my next DIY alarm then. The speaker would not fit on my bike anyway

I have thought about a vibration alarm for extra insurance when I lock my bike up during the day. There are now quite a few locks with alarms and even GPS tracking, but those seem like overkill to me. A cable lock and a Doberman or a "Bleep Bleeps" Sammy Screamer should work. the Sammy Screamer is controlled via a smart phone. It screams and also sends a notification to the phone if the sensor is moved.

Doberman SE-0304 Bag Protector Alert

Sammy Screamer - Motion Alarm by BleepBleeps

+1! Very thorough discussion.

Go to a big box hardware store such as Home depot and look at the door & window alarms. You could mount these in a dozen different ways that would set it off when the two halves are moved apart. They have small and lightweight models around the ten dollar range. Might be better than a motion sensor. I have bought one but not used it yet.

i use this Siren Alarm Lock Motion Sensor Security Padlock Bike Garden Shed Anti Theft Lock | eBay

I follow the same concept, make it inconvenient/noisy for someone trying to make off with the bike. I use ultra cheap Velcro around the brake levers, the wheels won't move making it hard to make a quite grab & go, anyone determined to steal the bike is going to take it anyway, I just want difficult.

I've heard of people attaching a string/fishing line from the bike to a tree and a bear bell/cowbell on the line so if the bike is moved, the bell rings. I suppose if the area is windy, the bell could ring but it might be a starting point. When I ride out at the camp/cottage, I generally have a bear bell with me: it is neither big nor heavy.