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Remote hatch release project

8K views 55 replies 17 participants last post by  MidLifeZ 
#1 ·
After researching, looking around, etc. I have decided to move forward with my Remote hatch release project to use my recently installed remote lock/unlock unit which has output for trunk release.

Here are the parts to be used:
$45 shipped. Could have gotten a few $ cheaper but this one said would be delivered by this Saturday.
Heavy Duty 2" Inch Linear Actuator Stroke



And two of these from Amazon, $13 each
Directed Electronics Inc 528T 12v Accessory Pulse Timer


What I am going to do is mount the linear actuator in the area where the arrow is pointing to. The signal from the remote unit will go to one of the 528T relays with it set to send power to the actuator, and retract it, for XX seconds, time to be determined. This will pull on the same cable as the manual handle. Then the other 528T relay will wait 30 seconds (maybe less) and send power to the actuator for XX seconds to expand it. This will leave the manual option in place and functional.

will post my progress this weekend.
 

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#4 ·
The one I purchased says it is 225 lb so fingers crossed
 
#3 ·
I would install a separate cable from the actuator to the latches. That way you don't strain the manual (original cable) and wear it out. The other problem you may find is that the actuator may not have enough power, especially since you must release 2 latches and they are not simultaneously released. You may require 2 actuators, one for each latch. You should still have back-up cables too.
David Teitelbaum
 
#5 ·
Good idea on separate cable, that is along lines of what I was going to do by having a new cable from the actuator to where the original cable from the manual handle attaches. The actuator I got says it is 225 lb so fingers crossed. I went with a linear actuator versus doing two solenoids with the thinking it would put less stress on the cables. i.e. instead of BAM! of a solenoid.
 
#6 ·
Install some emergency release cables. Here are some pictures of where I located mine. The best approach is to use a second cable set which will function when the primary cable breaks. In the two times I have had to figure out how to get the hatch open both were caused by the cable snapping at the distal end. So, to avoid going through what I went through (drilling out the bolts holding the boot floor in place - which is only the beginning of the fun, believe me. It is not easy to get the latches open even after you can get your hand blindly up into the rear boot). My approach was to drill pass through holes on the side of the latch where the springs are mounted and to run a second cable through those holes. Then I established a cable which exited through the driver side wheel well and another cable which was routed via a cable loop and exited under the car next to the right side of the muffler. The first picture shows the exit point for the cable on the driver side wheel well. It runs straight to the latch on that side of the car. A simple tug on the loop and the latch releases. The second picture shows the set-up on the passenger side. That cable pulls straight back on the latch and is routed 90 degrees by a loop which is fixed to the stud which secures the tail light cover. It is routed straight down and exits right next to the muffler. this is shown in the third picture. Again, a simple tug on the cable and the passenger side latch releases. Both of the pull loops are easily tucked away so that nothing is visible from outside the car. The holes drilled to accommodate the cable passing through the wheel well and the boot floor are smaller than a pencil lead. The cables are standard bike control cables from the local bike shop,

As I said, I have been through this hatch-won't-open thing too many times to deal with it EVER AGAIN!! :facepalm

I'm so done with it that I even cut slots into the boot floor bolts so that if the damn emergency release cables fail I can take the boot floor out without having to drill out the bolts.

You've hear of guys who wear a belt AND suspenders? When it comes to the hatch getting stuck closed I am wearing a belt, and suspenders, and I duct taped the pants to my body just to be sure! :D
 

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#12 ·
Install some emergency release cables.[snip] My approach was to drill pass through holes on the side of the latch where the springs are mounted and to run a second cable through those holes. [snip]
As I said, I have been through this hatch-won't-open thing too many times to deal with it EVER AGAIN!! :facepalm

I'm so done with it that I even cut slots into the boot floor bolts so that if the damn emergency release cables fail I can take the boot floor out without having to drill out the bolts.[snip]
Do you have a picture of the drilled latch? I think I remember you posting a picture on an older thread, but the search function here makes it difficult to find.

Thanks,
 
#7 ·
A corollary - never mount an actuator that opens the cover to the compartment that holds the power source for the actuator in the same compartment as the power source. If the battery dies, you can't open the hatch to replace the battery.
 
#9 ·
That is a problem for Bricklins. When the battery dies or if the doors don't work, you have to climb out the back hatch window! On Deloreans the door module would get stuck and hold the solenoids so you can't unlock the doors till the battery dies. Installing a back-up system is always going to be easier than dealing with things when they die and you have no back-up. If you do install back-up cables be sure to test them under all conditions so you have the best chance of them working. Use them once in a while too so you don't forget how to use them.
David Teitelbaum
 
#8 ·
#11 · (Edited)
Poked around a bit and this weekend will delve further into my idea of how to attach to the latch at the far rear left in the boot. Latch referring to is the one the cable attached to the handle is attached to.

The cable attaches on the left and to the right is a spring which after manually pulling the handle makes it return and ready for the hatch to be closed. The spring is held in by to "nibs/nipples" which the spring rest on. Going to take that latch out, marking first the exact location, etc. and look and see if could drill out the nibs. Would then use the hole to thread the cable which will attach to the actuator. If that does not work will have to look at a way to either attach a connecting point or have a piece welded on to which to attach the cable to the actuator.

May use a rod instead of cable since might be able to make so the rod allows the latch to slide to make up excess pull of the actuator and a rod would be much easier to adjust length of.

Will keep posted and post pics later...

I found a photo of the latch. The arrows show the nipples which I might drill out then insert the cable which attaches to the actuator. If ever needed to reverse it, i.e. remove the remote unlock, could easily put a rod there to keep the spring in place. Photo must be from a RHD Esprit since in my LHD the photo is a mirror image of mine, just FYI. The cable to the actuator would insert on the left and terminate on the right in the image.
 

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#14 ·
If you do use a rod you must allow for the other system (the manual release lever) to operate too. Otherwise one can prevent the other from working. One big advantage of cable is you do not have to be near or directly in line with what you need to actuate.
David Teitelbaum
 
#15 ·
I will take pictures of my set-up and post today.

As far as using a linear actuator, I like the concept. The only one I am aware of is Loren Stump and he used them to open and close the hatch, subbing them for the struts. He did not use them for cable pulling. If you come to rely on actuators alone the dead battery issue is a real consideration. I think if you go that route you need to create some externally accessible battery post connections so in an emergency you could power the battery even with the hatch stuck closed.

I also thought about tossing out the whole cable-based system and using release buttons mounted on the hatch (e.g. Quik-Latch). However, that requires drilling into the body of the hatch and I was reluctant to go that route. However, I still think that is a viable option.

One final thought. The quality of the control cables provided by Lotus is crappy. I no longer use them for the throttle or the rear hatch. I have them made by a custom cable shop in California. The quality is way better than whatever Lotus us selling nowadays and the price is not only competitive, but if I recall the throttle cables I had made were cheaper by a few bucks than Lotus OEM.
 
#17 ·
Ok. I have my cables made by Control Cables in Santa Fe Springs California. Their website is

Control Cables | Industrial Motion Controls | Street Rod Parts & Accessories

I have not had them make shift cables, but the did both throttle cables and hatch cables for me. If you send them an old cable and request a copy (or a copy plus some additional specifications) they will let you know if they can do ti and how much. My experience with them has been excellent.

Here's some pictures of my back-up cable release attachments to the latching mechanism. Sorry but its not easy to shoot a decent picture in situ (I love that "in situ" talk :UK: the Brits use it all the time!). Excuse that last one, it's a little fuzzy but I think they all show how I routed the cable through the center of the spring.
 

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#18 · (Edited)
#21 ·
A somewhat radical alternative - throw the whole cable mechanisms out and use two Quik-Latch fasteners mounted on the edge of the hatch.....

Quik-Latch.com Your Authorized Dealer For Quik-Latch Products

Big drawback is that you would need to drill the deck and I'm not sure how weathertight the button mechanisms are. They might seep water into the rear boot under heavy rain. The current product line does not include lockable latches but the company says those are coming.
 
#22 ·
Issue I ran into, besides using linear actuator would have required either some very complex combobulation of relays or my using a Arduino mini computer and such, is that the way the cable works is it pulls the left side latch and right side independently. I am confident the two separate solenoids will be easy to install, retain original handle and cables and only requires one relay to convert the low voltage pulse signal from the remote unit to 12 volt.
 
#24 ·
yup.. why did you remove it?
 
#25 ·
Several problems with Solenoids, they are a one time bang. With the sloppy and catchy latches, one press may not release both latches. You will need at least an 85lb solenoid to pull both catches or two solenoids.
A single linear actuator has more than enough power and is a continuous push/ pull. You will need to set up an actuator controller (for automatic operation) or a double pole double relay switch (for manual).
 

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#28 ·
Removed for several reasons.
The solenoid didn't always release both catches.
Cables stretch and even brake.
Cable stops can loosen and slide.
The entire archaic cable latch system is clumsy at best.
All the parts, latches, mounts, cables, lever, solenoid/s, struts and associated wiring and switches weighed more than the two actuators I ended up using.
Just plain coolness.
 
#29 ·
I am going to try with two solenoids from Directed Electronics, model 522T, one for each side. The relay(s) I am using are Directed Electronics 528T which has a built in timer. By having the timer my hope is to avoid synchronizing the two, i.e. can set the timer to send power to both at the same time. If need be can make so it sends power for say 5 seconds thus ensuring both solenoids do their jobs. As it is my hatch pops up a bit, clearing the latches, when using the lever from the drivers compartment so fingers crossed.
 
#32 ·
i.e. can set the timer to send power to both at the same time. If need be can make so it sends power for say 5 seconds thus ensuring both solenoids do their jobs.
This is what I did with the Elise, because even with only 1 solenoid it was not always opening with a very short pulse, so I increased the pulse to 1-2 seconds. This route should work well with 2 solenoids.
 
#30 ·
I tried a solenoid based pull system, one for each latch. I could never get it to work well and eventually removed it. Loren pretty much identified what the issues are with solenoids in this application.

Loren, are you using the quick-latch setup with the actuators? I thought your actuators powered the hatch up and down. How does the quick latch fit into your scheme?
 
#31 ·
(Elise) The touch activated Power Trunck Release system works perfectly

I don't know how similar the Esprit is to the Elise truck release, but a simple hidden power actuator in the trunk lid did wonders.

I got the smallest actuator available and then cut it down to about 1/2 the size. It all fits under the trunk release cover. You can't add a small actuator directly on the release point, or have a very small cord?

Here is the previous post:

http://www.lotustalk.com/forums/3008561-post171.html
 
#33 ·
My entensions are always to make it simple, modern, functional, serviceable, reliable, factory looking and most importantly LIGHT!
Unlike Solenoids, actuators are light, powerful, and controllable. Solenoids are loud, heavy (for the more powerful units) and momentary.
In my case the actuators replace not only the struts but also all cable/latch/lever system.
Rather than keeping the 6 pounds of cables and latches( in case of battery failure), I have two quick release hindge pins weighing a ounce and a half.
I also installed the small aluminum hood pins, this applies more pressure on the seal, takes some of the pull stress on the actuators and can allow me to remove the actuators all together (weight 4lbs.) and still lock down the hood.
I've installed the same pins on the front bonnet also for the same reasons.
 
#34 ·
Well back to square one, actually square two.. :)
Tested one of the solenoids and as someone here experienced, it was not strong enough. So, back to the drawing board for my original idea to use linear actuators. As noted prior, my roadblock was in how to wire up the relays. After many hours I finally found the solution mostly at this site Cheesycam DIY Auto Reverse Polarity Motorized Video Slider ? Update | CheesyCam

While he is not using a linear actuator like I am, he did provide part of the missing pieces in that his goes back and forth over and over which meant all I had to do was figure out how to A. Get it to send power when activated which would retract the linear actuator and then B. pause before returning and then when return to stop so it is ready for the next press of the trunk button on the fob...

I spent a good chunk of Saturday bench testing and succeeded! Taking the wiring diagram from cheesycam, I modified it per the attached so that the two DEI 528T relays (basically DPDT relays with a timer function which can be wired up such that it either waits before sending power or sends power for a specified time [5-90 seconds] then cuts it). Here is the magic:

With the linear actuator extended, 528T #1 receives pulse signal from remote control unit when trunk button on key fob pressed which causes 528T #1 to send + for 10 seconds to #6 on the socket base in which the DPDT Coil Power Relay is mounted which retracts the linear actuator. When retracted it depresses the microswitch (Switch A in image). The same pulse signal also starts the 'pause' timer in the second 528T (528T #2) to start. Once 30 seconds have passed 528T #2 sends ground to the other microswitch (switch B in the image) which triggers the linear actuator to extend until it hits microswitch A. Since 528T is no longer sending power the linear actuator stops and awaits the next time the trunk release button is pressed.

Here is how the two DEI 5628T's are connected:

528T #1

528T Connection
BLACK/WHITE Trigger from remote
ORANGE Not used
YELLOW & RED + Constant
BROWN to 6 on dist block
BLACK Ground

=============================================

528T #2

528T Connection
BLACK, BLACK/WHITE, YELLOW Ground
RED Brown from 528T #1 (+ voltage)
ORANGE Switch A #1 in image
BROWN Not used

Here are the other parts I got:
DPDT Socket Base
FRYS.com*|*NTE
Coil Power Relay DPDT
FRYS.com*|*NTE
MICRO-SWITCH SNAP ACTION WITH LONG LEVER
FRYS.com*|*PHILMORE


I got some stranded cable for a lawn mower throttle to use to pull the two latches which will be connected to the actuator with turnbuckles so I can adjust to make sure not pulling too much or too little on them. Just need to finish hiding, mounting, routing wires, etc. I mounted the relays and actuator on a 1/4" thick piece of lexan I had laying around which is hidden out of sight in the left rear are of the boot.

I tested it and worked terrific, took a few cycles to get the turnbuckles adjusted so length were correct but not hard to get done. When get all permanently mounted up will put additional nuts on the turn buckles so they are not able to move.

OEM boot release works exactly as before too! I will post more photos of it all installed and a video though will be a week or so with the holidays here and no heat in the garage. We went from 74 degrees on Saturday to ~20 on Sunday here in Dallas so, no..
 

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