Automatic Trunk Opener

[Spizzak]

So the inspiration for this project came from what a pain in the *** it was to lift the passenger seat because it required two free hands. I wanted something that I could pop the trunk with without having to put everything in my hands down first.

Basically what I did first was JB weld a cheap hardware store spring on the lock mechanism which now lifts the seat up far enough so that it doesn't lock back into place if i let go of the key so now I could open the trunk with just one hand.



This pretty much solved my problem but I had time to kill and an idea so I decided to make things even easier.

I wanted to use a solenoid powered by the battery to activate the push cable that releases the lock mechanism so first I measured the force required to pull the cable (about 1.5 lbs) and then bought a 12V solenoid online that could provide that much force (turns out the one I got is actually way stronger than what I needed but w.e)

Once I found a good location for the solenoid I needed to cut off the metal sleeve that was keeping me from bending the push pull cable. After that I cut a slot into the core of the solenoid to hook the cable into. Once I got it all mounted (I just used zipties- they seem to be enough) I just had to wire it up.









For security I had to make do the wiring in a way that the trunk would only open when the key was in the ignition. Originally I was gonna use the license plate light to power it but the solenoid draws way too much current so I used a relay that was connected straight to the battery and instead switched by the license plate light. Then I just installed a switch on the undertail to control the solenoid.

Relay wrapped in tape


Leads for switch


Button Location


Diagram


I also added a 7A fuse inline with the solenoid just to be on the safe side. All in all I'm pretty happy with the project, the only two things that concern me are accidentally hitting the switch while riding and if for some reason this system fails I'll have to use tools to remove my seat.

Cost Breakdown:
Solenoid: $35 shipped from DigiKey
Relay, fuse, fuse holder: $10 from Sayal Electronics

I had everything else lying around the house. As for tools, I used a drill, dremel, angle grinder and soldering iron.

Let me know what you think!

[Jlin]

Interesting, can you post a video of it in action?

[Spizzak]

I wont be going home till reading week but I will then.

[Jlin]

I wont be going home till reading week but I will then.

haha understandable, same here.

[Spizzak]

Here's a video of it working

http://www.youtube.com/watch?v=Kc_rpKP76zI

[Jlin]

Here's a video of it working

http://www.youtube.com/watch?v=Kc_rpKP76zI

nice job that's so much more convenient than using the key.

[Jahnnyb]

I did this with my 929's trunk after putting in an undertail kit. Well worth the effort and no more dam key to use! The only difference was that I mounted my pushbutton on the side of the bike where the battery sits under the seat (small red button). This way it stays clean and rather than use a relay I just grabbed power off my tail light circuit as the solenoid I purchased doesn't draw that much power. To save on shipping you can pick up parts at Princess Auto (low power solenoid for $9), Canadian Tire (bicycle brake cable) and the Source (wiring and a momentary pushbutton). When you run the cable make sure to minimize the amount of bending otherwise the solenoid isn't strong enough to pull on it and it won't fully retract either. I've used it for a full season with no issues with blowing a fuse or it's operation.

[americrack]

That's freaking clever. And no I'm not being sarcastic.

[frekeyguy]

what happens when that solenoid fails? or relay fails?

[Jahnnyb]

If it breaks no big deal for me as the driver's seat pops off and I can pull on the cable to open the trunk. So, it would be an easy fix if it did fail.

[Spizzak]

Yeah I can take the front seat off if something fails.

[brian997]

Jeez Dan you have way to much time on your hands haha... But kudos on the mod...
Is engingeering not enough work for you lol?

[Spizzak]

haha what else am I supposed to do during reading week.. study?

[aznk]

I have an idea. You can also tie it in with your alarm system, if you install one.

For me, I didn't want to fiddle with the ignition-kill/auto-start feature for my alarm so there are extra wires left over.

It would probably be pretty easy to tie it with the auto-start feature of the alarm and now you have a remote trunk opener!

[Wingboy]

Cleverly done.Mine is the lazy man's version.

[bassguitar]

Pretty cool idea.