Weston
10-05-2003, 11:35 PM
Post your DIY security ideas and comments... I'm talking about stuff that you can't buy and that thieves generally wont expect. A lot of this works in conjunction with an alarm. A 2-way alarm (ie one that'll page you) is a great idea.
If you need help, post it here, don't PM me because the point here is to help everyone. And I can't explain everything to anyone, some of this is a little advanced.
Here's my basic stuff:
Kill switches - Don't waste your time with starter kills, you can start most cars without the starter. And don't let your alarm control this... in most cases, once the alarm is disabled (and I bet it will be), it's done protecting your car. Kill something vital like fuel or ignition, use an appropriate relay if it's a lot of current, and make sure every part of it is well hidden... don't put the switch somewhere obvious like around the driver's side dash (or underneeth it), ash trays, etc. Make sure it's nowhere that can get bumped, especially while driving.
Hood cable reroute - very important for Hondas... route the cable through the engine bay so that it cannot be access from outside. Disconnect the cable at the lever, take off the driver's side fender liner and cut the clips, then pull the cable all the way back until it's entirely in the engine bay, then route it back through the engine bay and firewall to the lever. Also maybe install some piece of metal or something to block access to it around the latch so that they can't reach up through the bumper, if your car doesn't have one already.
Power unlock disable - also very important for Hondas. disable the power unlock switches, so that the car cannot be unlocked with a coat hanger. Cut the unlock wire completely, or throw a relay on it connected to the ignition (so the locks work when the car is on, but not when off), etc.
Miscellaneous electrical things - make the alarm be triggered by the trunk sensor, hood sensor (if you have one, otherwise add one), and power unlock switches. Also add extra sirens (put one inside the car too), horn honk output, and more lights (flashing headlights, blinding strobes inside, etc)
More advanced stuff (ie stuff that isn't so easily explained how to do yourself):
Defensive power locks - when the alarm is armed, mine disable the power unlock switches and triggers the alarm when they are pressed, and if the doors are somehow unlocked, it triggers the alarm and sends repeated lock pulses until they are locked again. So, even if you have a key, the doors will lock right back up and the alarm will be going nuts before the thief even knows what happened. It requires modifying the passenger's side so that it can detect if it's unlocked (otherwise you can only detect when it's unlocked with the key) and you have to build your own circuit (some diodes, transitors, resistors, capacitors, a 555 timer chip, and possbily relays depending on the car).
Add more alarm trigger inputs - some alarms have only one auxillery input, some have none. You can usually use diodes to add more, but that only works if the input being added is the same polarity and is always open (ie disconnected) until it's triggered. If one is closed or triggered when the alarm is armed, it'll disable all of them. So, you can build a circuit to properly add more and accomidate the ones that may be initally closed. I haven't built one yet, but I'm thinking an XOR gate for each circuit, all connected in a series, then a final XOR with a latch that's active if the output from the series is high when the alarm is armed. That'll trigger the alarm if any of the inputs change and it'll always do it with a low -> high transistion (many alarms wont respond to high -> low).
Proximity sensor + fog lights - most proximity sensors are prone to false alarms, so making them set the alarm off isn't the best choice. My current security project is to mount my old fog lights in a place that's somewhat hidden but will allow them to light up the thieves. The only hard part is finding a good place to mount them. My best idea so far is the rear wheel well, which is open to the rear bumper... I could mount them on something metal and point them out so they'd light up the sides of the car, but I'm not sure how well that'd work. The wiring may be accessable to a thief, so I'd have to use some trip wires to trigger the alarm if someone tries to disable them.
Another idea I have is to use a basic computer system connected to a GPS, digital camera, cell phone, and other stuff. It could call me and tell me where it is, and/or upload pictures and it's location to the Internet. I'm a software developer and an electrical nut, so it's likely that this will happen before too long, especially with those prepaid cell phones and the dirt cheap cost of decent computer parts. The only thing I haven't figured out is the connection to the cell phone because I have to see what phones and data options (if any) are available first... I'm going for a cheap prepaid phone, so there's no monthly cost or anything.
If you need help, post it here, don't PM me because the point here is to help everyone. And I can't explain everything to anyone, some of this is a little advanced.
Here's my basic stuff:
Kill switches - Don't waste your time with starter kills, you can start most cars without the starter. And don't let your alarm control this... in most cases, once the alarm is disabled (and I bet it will be), it's done protecting your car. Kill something vital like fuel or ignition, use an appropriate relay if it's a lot of current, and make sure every part of it is well hidden... don't put the switch somewhere obvious like around the driver's side dash (or underneeth it), ash trays, etc. Make sure it's nowhere that can get bumped, especially while driving.
Hood cable reroute - very important for Hondas... route the cable through the engine bay so that it cannot be access from outside. Disconnect the cable at the lever, take off the driver's side fender liner and cut the clips, then pull the cable all the way back until it's entirely in the engine bay, then route it back through the engine bay and firewall to the lever. Also maybe install some piece of metal or something to block access to it around the latch so that they can't reach up through the bumper, if your car doesn't have one already.
Power unlock disable - also very important for Hondas. disable the power unlock switches, so that the car cannot be unlocked with a coat hanger. Cut the unlock wire completely, or throw a relay on it connected to the ignition (so the locks work when the car is on, but not when off), etc.
Miscellaneous electrical things - make the alarm be triggered by the trunk sensor, hood sensor (if you have one, otherwise add one), and power unlock switches. Also add extra sirens (put one inside the car too), horn honk output, and more lights (flashing headlights, blinding strobes inside, etc)
More advanced stuff (ie stuff that isn't so easily explained how to do yourself):
Defensive power locks - when the alarm is armed, mine disable the power unlock switches and triggers the alarm when they are pressed, and if the doors are somehow unlocked, it triggers the alarm and sends repeated lock pulses until they are locked again. So, even if you have a key, the doors will lock right back up and the alarm will be going nuts before the thief even knows what happened. It requires modifying the passenger's side so that it can detect if it's unlocked (otherwise you can only detect when it's unlocked with the key) and you have to build your own circuit (some diodes, transitors, resistors, capacitors, a 555 timer chip, and possbily relays depending on the car).
Add more alarm trigger inputs - some alarms have only one auxillery input, some have none. You can usually use diodes to add more, but that only works if the input being added is the same polarity and is always open (ie disconnected) until it's triggered. If one is closed or triggered when the alarm is armed, it'll disable all of them. So, you can build a circuit to properly add more and accomidate the ones that may be initally closed. I haven't built one yet, but I'm thinking an XOR gate for each circuit, all connected in a series, then a final XOR with a latch that's active if the output from the series is high when the alarm is armed. That'll trigger the alarm if any of the inputs change and it'll always do it with a low -> high transistion (many alarms wont respond to high -> low).
Proximity sensor + fog lights - most proximity sensors are prone to false alarms, so making them set the alarm off isn't the best choice. My current security project is to mount my old fog lights in a place that's somewhat hidden but will allow them to light up the thieves. The only hard part is finding a good place to mount them. My best idea so far is the rear wheel well, which is open to the rear bumper... I could mount them on something metal and point them out so they'd light up the sides of the car, but I'm not sure how well that'd work. The wiring may be accessable to a thief, so I'd have to use some trip wires to trigger the alarm if someone tries to disable them.
Another idea I have is to use a basic computer system connected to a GPS, digital camera, cell phone, and other stuff. It could call me and tell me where it is, and/or upload pictures and it's location to the Internet. I'm a software developer and an electrical nut, so it's likely that this will happen before too long, especially with those prepaid cell phones and the dirt cheap cost of decent computer parts. The only thing I haven't figured out is the connection to the cell phone because I have to see what phones and data options (if any) are available first... I'm going for a cheap prepaid phone, so there's no monthly cost or anything.