ground too weak to power a relay

i have an old alpine motion sensor that seems to work fine except for the trigger output wire not being strong enough to power a relay. it meters ground and will work well enough to power an led. i need to try to find a micro relay somewhere and see if that works but are there any other ways to strengthen a ground? the whole point of this is to not spend any money. i have a viper 5301 in my fiance's car and with a spare siren and a couple relays i built an add-on alarm unit (one of these days im going to draw a diagram if anyone wants one) so any help is appreciated. Brandon MECP Basic Cert. Best Buy Store 229

Use a mini from radio shack, i.e. the circuit board type. DEI also market one, prewired. Having said that, it should put out about 100 milliamps which should be enough to triger a normal bosch type relay.

Why are you trying to trigger a relay with the sensor?  The alarm should have an instant negative trigger wire to connect a sensor to.  I can give you enough current capacity to trigger a relay, just tell me why you have to trigger a relay.

https://www.the12volt.com/installbay/forum_posts.asp?tid=114792&KW=2n6491#556471 The connection labeled to ground out while armed is where you connect the output from your sensor.  The right connection is going to connect to 85 of your relay.  Connect power to 86 of the relay.  When the sensor triggers, the transistor will take the small current signal and amplify it to be able to energize the relay.

According to my knowledge 200ma is enough to trigger relay. Are you sure you dont have a faulty relay.

By a reed relay from radio shack.  They need ~6mA of current to switch and will be enough to drive a standard relay, or can be used to power some lower current stuff.Kevin Pierson

A typical Bosch/Now Tyco relay draws 160 milliamps of current.  I have never seen a sensor capable of that much current.  Reason being is a negative instant trigger alarm wire needs only microamps of current capacity.  

a transistor, i knew there was a way to do it. see i have a 2 way remote start on her car, thus the door trigger input doesnt do anything except for manual tranny mode. what i did was wired up a momentary-to-constant relay with 85 being the cars door trigger/the wire from a shock sensor isolated from each other, and 86 being + from the ground when aremd wire (another relay obviously). then that sticky relay as i call it powers the siren. so as long as the system is armed, a momentary pulse from the door, shock sensor, and now that i know how to do it, the motion sensor will trip the siren until the system is disarmed. the viper 5301 will report an alarm trigger to the remote via the horn wire, so with a couple relays i made the 5301 into the 5701. downsides to this frankenstein add on: 1, no warn-away 2, no chirpy chirpy, only the horn for locks and unlocks new development in my own head... im going to have to make something that switches to a cap driven relay once the siren goes off to achieve a controlable siren duration. yes i see that this is a big rube goldberg, but im thinking i can get all this done with about 6-8 micro relays. now before the flaming starts, im not doing this to be cheap, its more of a mental exercise, and to see if i can do it. i pride myself on my superb diagnostic and problem solving skills, and its doing things like this that keep me on my toes. its like Latched On/Off Output Using a Single Momentary Pulse, you could easily put an actual on/off switch in there, but someone sat down and thought this out and someone out there has found applications for it