Hi All, welcome to my first Instructable!

I may not follow the rules here...but that's because this is more of what I did for my particular car and will vary depending on the car you have. Use this as a guide for your own project...an idea for what is possible!

I've been researching campers, camper conversions, car campers etc. etc. for several years now. In Dec. 2015 I purchased a 2010 Nissan Cube...and immediately wanted to make it into a camper. The interior space is relatively massive for such a small car. It's roughly 4ft wide...over 7ft from dash to tailgate...and almost 4ft in height! I'm 6'1"...so this was plenty for me.

I have a confession to make. This is version 3.0 of this camper. I tried to make a fold-out framework that just didn't work. I then made a simple platform with enough room for myself and went on a road-trip out to the east coast! It certainly worked, but it was cramped and there wasn't a lot of storage space.

DISCLAIMER: I am from Canada...and grew up with the metric system...but will more than likely use "feet" for measurements. I don't really have an excuse...it's just familiar and relative to dimensions of wood available at the big orange home renovation centre local to me. It's also difficult to find a measuring tape with centimetres on it - it's rare - most have only inches! There may be 12 different ones on the shelf and only 2 will have metric alongside inches. My apologies in advance to those that are sensitive to international standards!

Also...for some reason everyone does this but it should be OBVIOUS...read this at your own risk to your self and your vehicle. This is meant as a guide and nothing else.

Above all else...ENJOY and hopefully this will inspire you to make your own as so many others have done for me!

Step 1: Get a Car!

SO...that's my car. She's a beauty, ain't she?

1. Look at your car and assess what you have

2. Measure the interior space...is it big enough?

3. How do the seats fold down?

In the Cube, the rear seat-backs fold down and the front seats fold flat, backwards, making for a nice open area above. Version 2.0 of this bed was a simple platform that wedged under the rear seat and was supported at the front by a box sitting on the front seat. For the new and improved version 3, I removed the rear seat to provide more space as I didn't need it for passengers. This makes the rear cargo area huge!

4. How many people do you want to sleep inside?

5. How much STUFF do you want to take with you and what storage do you need?

6. Start measuring and cutting wood!

Step 2: Materials and Tools

Dimensional construction lumber is easy to work with and relatively cheap. I used the following in my build:

Materials:

4'x8' sheet of 3/4" plywood
4 or 5 2x4's and scraps
2.5" construction screws
1.5" screws for attaching smaller items
piano hinge
draw latches
Bungee cords

Tools I used:

Cordless impact driver - these are essential for framing-type projects like building a deck or walls...or in this case a bed for your car. They allow you to tightly and securely drive home a screw without stripping the head like you might with a regular drill or over-screwing and ripping through the material. You can still do that...but it's less likely.
Hand-held circular saw - for ripping the plywood into lengths etc. also called a Skilsaw as they're the big brand.
Jig-saw - for cutting curves in plywood and for straight cuts if you don't have a Skilsaw.
Table saw - for ripping 45 degree cuts in 2x4 when making the french cleat. You could do this with the Skilsaw or even a jig saw but a table saw is the best for this.
Palm sander - used for cleaning up rough edges on the plywood. Splinters in your butt are BAD! You could easily do this by hand of course...the sanding, not the splinters.

Step 3: The Frame

Planning

I wanted to have a stationary rear platform for cargo and storage even when I wasn't camping. I don't actually know if I'll use it this way, but I like things to be multi-purpose - if I'm going to go to these lengths then I want it to do more for me. It's a time and money investment so I might as well get the most out of it.

Conversely, try and keep the construction simple. Version 1 of my Cube Camper was a failure because I tried to make it too complicated. My first attempt was trying to recreate the Swiss Room Box (http://www.swissroombox.com/) as it is something like $3000 and I figured I could. Well..if I had a CNC and better materials...I probably could! But alas, I do not...and it was a wreck.

In Version 3.0, I wanted few moving parts. I went through several mental planning phases - arms that swung out to support the front, or a hinged platform attached to the rear platform. There were too many interior obstacles to overcome. This would also make the main body of the bed VERY heavy and hard to move in and out of the vehicle.

I was going to make it a foot high as this just cleared the front seats, when they're folded down, and gave me maximum headroom. I changed this half-way through making the rear platform at 16 inches as this gave me more storage and didn't drastically impact headroom.

Construction:

Each platform's frame is roughly 36"x36". The rear one has legs that are 16" long. I also added centre supports for the top. The rear platform has one across the width because I planned to have a lid and this is where the hinges would mount to. I added one perpendicular to this, on the front platform, to support the slats for the top (more on this in the next step)

This ain't rocket-science. I measured and cut the wood quite accurately, but in screwing it together I just laid it on a flat surface and screwed it together. It's framing...not cabinetry. There are some lovely examples of better craftsmanship on here...but hey...it's a bed in my car!? I don't really care what it looks like as long as it's functional.

There is a french cleat that mates the two halves. I also added a latch on either side to lock the two halves together. This made the bed very solid...a wonderful addition.

If you don't know what a french cleat is just do a search for it here on Instructables. Lots of people have used them for many different projects! It's a very versatile method of hanging a load from a fixed mount - DIY TV mounts, headboards, workshop tool walls, floating shelves etc.

I could see this being made out of pallets...that would be a neat use of recycled materials...just thought of that as I write this...DUH!

I also added a 45"x12" plywood plank to support the front platform. It just sits loosely under it and on top of the front seat-back's pivot point. This is one of the highest points and a strong one too as it supports the back and has to take the G forces during an impact. Plus it was a VERY SIMPLE solution to supporting the front! I plan to add one half of a matching french cleat so I can extend the rear deck when the seats are in the upright position - this way the same piece can be used with the rear deck as a full cargo bed with storage underneath. See...DUAL PURPOSE and so easy to do.

Step 4: The Bed's Bed

So...now that you have a good solid frame, you need a top for the bed.

I mentioned in the previous step that in creating the frame I added centre supports, on the front half, for bed slats. The slats came from version 1 of this bed. There's a kind of circle of life thing here...parts from the first version being used in a later iteration of the same idea.

The plan for this changed as I built it...you start with an idea and as it progresses you change it because you see it can be done more efficiently or with less material or SMARTER. Even as I write this, I want to remove the slats and have a hinged bed top that is attached to the rear platform. This would make the rear half heavier, but it would make the part you have to move regularly (the front bit) lighter.

It's a work in progress.

Anyway...the rear is more important as it's the foundation. The back of the Cube tapers towards the tailgate. It's 48" at the passenger doors but 39" at the rear. Measure carefully and trace the measurements onto your plywood. Some people like to make a template from paper or cardboard...this never seems to work well for me. If you're good with a measuring tape it should be fine. Mine turned out rather well...I didn't want the platform rubbing and scratching the interior so I intentionally made it an inch narrower. I figured this out as I was test-fitting the pieces...rubbing and scratching the interior in the process! Arrrghh...

***Take heed of my advice...make it smaller than the actual dimensions of the vehicle. For one, you'll prevent damage. Secondly, once you get a mattress on top, you won't notice the gaps anyway. It will also make it easier to get in and out of the car as it won't be such a tight fit.***

The top actually ended up being roughly 45" in the largest dimension and 41" at the rear. The slats were 40-45 depending on where they were on the frame. I cut them to length to follow the contour when it's stowed in the back.

Screw the plywood to the frame!

The Lid

Once the deck was screwed down, I ran the Skilsaw along the width to make a lid. While it was still screwed at the back, I attached the piano hinge and then unscrewed the back half of the deck, creating a lid! The cut was made above the supporting member, so I adjusted the blade height to the same as the thickness of the plywood. This prevents cutting into the frame underneath.

Safety

I used some screw-in eyelets to anchor the bed to the car. There are cargo tie-downs inside...a couple of bungee cords and it's solid. These also prevent the bed from tipping, where the two halves meet, when you get in and out of the car.

In the pictures there is a horizontal support that I later removed to provide better access to the storage space. I moved it back (forward?) and attached it to the existing hinge-brace in the middle. This increased support for the top and it was already the right size! The lid is barely effected by removing this piece. Since this is the "foot" of the bed...it's not taking much weight and so doesn't really need it anyway. There is still adequate support on three sides of the lid.

Oh and sand the edges...the number of splinters I got while making this was not fun. One less thing to worry about while camping and it looks better.

Step 5: Use the Bed

That's pretty much it!

When stowed, the front sits on top of the rear. When deployed, you put the support plank down, the platform slides forward and drops on to the cleat, and you do up the latches.Do remove, the front unlatches, lifts up and then slides back on top of the rear platform. Done. I use the latches to anchor the front to the rear - DUAL PURPOSE and SIMPLE! See a theme here?

I also made a little tee support to go between the front seats to support the front platform in the middle.

The sleeping area is at least 72"x40" and wider at the front where it's 48". Plenty of space for two, albeit close, people. It's certainly wide enough to fit a twin mattress or something custom fit to maximize the space. I have a single flip and fold foam pad that'll be using for the time being. I was also experimenting with patio chair cushions. There is almost 3' of head room too!

Additions:

I got a cargo net from Amazon to hold my stuff when I'm sleeping (you can see it in the last picture). It attaches to the "OH SH*T" handles and happens to be in the perfect place. It doesn't brush against my head while driving either. I can also use it for it's intended purpose when I don't have the bed in there - DUAL PURPOSE! WOOOOOT!

I am going to make some screens for the windows too...do a search for window screens on Instructables...so easy and a great/essential idea.

I may also make a chuck box that fits in the storage area. This will also provide support for the lid if needed - DUAL PURPOSE - HA HA.

I'm still working on this, so I'll more than likely update this as I make modifications. Like paint maybe? I was thinking of painting the rear deck with truck-bed liner...and I may still remove the slats and do a hinged bed for the front...but it's so SIMPLE right now and the slats have a DUAL PURPOSE of providing strength. Ok that's the last time I swear.

Thanks for reading...hope you enjoyed it.