Hi. This is my first instructable so I have decided to start with a simple one. By the way English is not my native language but I will try my best.
I own quite an old campervan wich I have enjoyed extensible and modified even more.Today I have been adding a dashboard indicator that will light up and warn me if I turn the engine on and I have left the jacks deployed. This is dangerous as if I were to drive off with them like this they would probably break off. I have to admit I had half the job done as the camper had the indicator already factory wired to the retrractable ladder but I will try to explain this in case someone doesn't have this installation included.
Step 1: Factory Installation Explanation
This particular camper had this system already wired to the stairs as I have said before. this installation consisted of the following. A red cable wired into the vehicle fusebox through a hole on a space of an accessory the vehicle didn't include. this cable had a faston male type connector and was plugged directly into a fuse terminal which gets positive power whenever the car ignition key is on the ON position, This is important because you only want the indicator to light up when you are going to turn the engine on and probably drive away. If you were to wire this to a battery direct cable the indicator would drain your battery the first day you would park and deploy your jacks. To find were to connect your positive you can use a multimeter on the DC mode touching the negative probe to any exposed metal plate and looking for a positive (around 12v) voltage that drops down to 0v when you turn off the ignition key.
In the back of the camper there is a Normally closed switch that is pressed when the stairs are stored away. I will not explain this in more detail as this is exactly what we are going to be doing in the instructable. But do notice the purple wire that is connected directly to the negative terminal of the light indicator. the black wire is grounded behind the switch as we will be doing later.
I don't have pictures of the original indicator as this was an old neon 12v light which was near its life end. I do have pictures of the custom made indicator I installed in its place. it includes a powerful 3W red led very under driven, as it was excessively powerful, behind a translucent cut-out filled with resin in the shape of a warning symbol and 6 rectangular leds that give out the kitt effect. Very overkill for the job, I know, but I enjoyed making it, I also recycled for this a switch blank for yet another accessory not included in this vehicle. I will try to make a video of the effect and maybe post an instructable of this another day. This indicator has its positive terminal wired to the same red cable that goes straight to the fuse box and its negative terminal to the purple wire that comes from the stairs switch.
Step 2: Beggining the Instructable
Ok. Lets start with the instructable part.
In the first two pics you can see the jack folded away and deployed. this particular model is bolted to a metal bar that goes straight up to the camper floor. My first idea was to add a metal plate in between the jack and the metal bar in which I could install a switch that would be pressed by the jack when it was in the stored mode.
This part list is per jack, multiply for whatever many switches you want to install around your vehicle.
For this instructable I used a scrap piece of iron angle that I had cut off some workshop shelf legs that were too long. this are adequate as they already come predrilled.
The second thing you will need is a sturdy normally closed NC push switch, it has to be non latching. you can also use a 1p2t push switch like I did. I chose to go with a stomp foot switch, in particular this model:
you can get them relatively cheap in this page but the most important feature which made me decide on this model is that they are stomp foot switches. this means they are designed to be stomped on by the feet of heavy metal guitar players when playing live in concerts and in need of that extra powerful guitar overdrive when bursting out on a metal solo. I don't think you can get more heavy duty on a switch than that. this particular model is a 1p2t, meaning you have both the Normally open and the normal closed connector, apart from the common connector. so once again you will have to pull out your multimeter to find out which two terminals will read low resistance when the switch is not being pressed.
I also used a rubber washer to reduce the impact the jack gives the switched when pulled up as mine is spring assisted and springs up very energetically, but this is not necessary.
3mm rivet, or any other means to attach a wire to a metal plate.
plenty of wire, I am using 0,5mm black wire, enough for the 8*0mA my indicator draws.
I also used the opportunity to swap the bolts for a new set as they were quite rusty and scraped off plenty of dirt, but again this is optional.
Step 3: Presentation and Planning
This step depends completely on what you are working within my case. the switch had an appropriate length to be pressed by the jack when being installed right next to the jack mounting bracket, and the scrap iron angle had holes which were nearly spaced out to fit the holes on the mounting bracket however notice how i did have to make them bigger in a particular direction to fit with the jack holes, I did this with a round metal file. I don't advise using a drill unless you have an appropriate drillbit as one of to things can happen, if the drill bit is smaller than the existing hole the bit will easily break. and if it is larger it might get stuck damaging your wrist. notice that the holes are not round but more like oval.
Then I used my angle grinder (protection guys, gloves and glases minimum, be safe) with a cutting disk to cut the metal angle to the jack bracket size and the flap which I folded inwards with combination of vise and hammer and which will hold the switch. try to measure this flap that the switch ends up being completely pressed but notice the switch is adjustable in height by means of the nuts it includes.
Don't forget to round out the edges and clean the cuts so not to leave sharp and dangerous edges. Be safe
I hope in this pictures you can see how the folded flap holds the switch just in placed to be pressed by the jack when the metal angle is bolted in its place. I also had to enlarge the hole for the switch to fit in. File work again.
At this pòint it is a good idea to check the switch is correctly pressed when the jack is folded in and out. Don't be afraid to use the multimeter again to double check
Step 5: Wiring
You need one of your terminals on the switch to be connected to ground(any metal surface near, like the metal angle we are using) and the other one soldered to the wire that goes straight to the indicators negative connexion (this will be my purple factory installed cable).
Drill a 3mm hole on a metal surface that wont interfere with anything else. I am using the excess metal of the flap that isn't touching the switch.
As i wasn't going to bother to look for a terminal connector and solder it, I went with an improvised connection. I twisted the copper of the wire around a rivet to get it in the round shape and then soldered the wire, the solder will not stick to the rivet as it is aluminium so then you can remove it and admire your improvised connector.
Remove paint from the metal plate if you don't have enough exposed metal and install the "connector" to the metal plate with your rivet. Now is a good time to spray paint the whole thing to protect it against rust. just after the wire is firmly attached to the metal plate and before installing the switch which could be damaged with the paint.
Step 6: Watch the Paint Dry
Once you are over watching the paint dry it's time to put everything together.
firstly remove some paint around the holes for the bolts to obtain a good electrical connection between the metal angle and the vehicle chassis
I did fill around the switch with heat glue t prevent it from filling with dirt, not essential again.
Install the switch in its place and solder the ground wire to one of its terminals. Solder enough wire length to reach the purple cable without it being stretched.
Install the jack in its place with the original bolts (or a new set) with the metal angle in between and admire your creation.
Once you have all the switches you want installed, solder together the ends of all the cables to your purple wire and you are finished. whenever you turn the ignition on and have anything deployed on your camper the warning indicator will light up.
I will try to make a video to show you all how it ended up. Thanks for reading.
By the way I noticed some of the pictures are taken of the left set-up and the rest of the right set-up, that is wy some of them look the other way round, sorry about that.