2"=1' Scale Dollhouse

Most dollhouses are made to a scale of 1" to 1', or 1/12th. A Barbie doll, on the other hand, is about 12" tall. Does this mean that Barbie is twelve feet tall? I know she's disproportional, but is it really that bad? No, Barbie is to a scale of 2" to 1', or 1/6th. So she won't fit in a normal doll house.

I started building a Barbie-scale dollhouse for my daughter in mid-February. I had to take a hiatus for several months, but I'm finally back at it. The doll house is modeled after our own house - an 1860's Italianate Town House - with a few simplifications to increase buildability and playability.

Italianate - key features are the cube-like shape, hip roof, chamfered columns, and double brackets everywhere.
Italianate - key features are the cube-like shape, hip roof, chamfered columns, and double brackets everywhere.

The doll house is 24" wide, 36" tall, and 12" deep. (Like most doll houses, it's unrealistically small: scale 12' wide, 18' tall, and a mere 6' deep.) The walls, floors, and doors are made of my favorite building material, 3/16" Lauan plywood. The molding is made from a pine 2"x 4", ripped into 3/4" square (more or less) pieces and then into whatever shape was required.

Doll House under construction.
Doll House under construction

Doors

The interior door is made from 3/16" Lauan with strips of 1/16" cardboard (the back of a pad of paper) glued to the surface to give relief. The trim is 1/8" x 5/16" pine, overlapping the door opening by 1/8" on one side of the wall, and aligned with the door opening on the other. The hinges are 3/4" x 5/8" brass hinges, held in place by absurdly small screws.

Interior Door
Interior Door

Drilling the holes into the frame to accept the screws was quite a challenge. The first problem was that the holes had to go into the frame exactly on the glued joint between the pine molding and the plywood wall! As the glue is harder than the wood, the drill bit wandered into either the plywood or the molding, and the hole ended up in the wrong place. I solved that problem by drilling a 1/16" hole in a piece of 1/8" thick angle iron and using that as a drill guide.

The second problem was that the 1/16" drill bit that I was using was so short that I couldn't get my drill close enough to the wall to make a hole even close to perpendicular to the surface. I solved this problem by grinding the end of a welding rod into a rough drill shape - this let me hold the drill outside of the dollhouse and guide the bit with my fingers. One hand on the drill, one on the flexing drill bit, and one on the angle iron drill guide. Good thing having three hands runs in my family!

Door Hinge
Door Hinge

Windows

The windows are Plexiglass, cut to size on my table saw. My first cut was made with a 24-tooth carbide-tipped ripping blade, but it chipped the edges of the cut. Later cuts were made with a fine-toothed plywood blade and came out glass-smooth! I was able to get all the windows out of a single piece 18" x 24" of 1/8" Plexiglass. I really wanted 3/16" to match the thickness of the walls, but I couldn't find any. (Granted, I didn't try too hard.)

Window Molding
Window Molding

The molding around the windows on the outside is 1/8" x 3/4" pine on the sides, and 3/4" x 3/4" "cornice" trim on the top and bottom, overlapping the window opening by 1/8". As usual, all trim comes from a piece of 2"x 4" ripped to size on my table saw or band saw. To keep the narrow pieces from being sucked into the table saw between the blade and the table, I made a zero-clearance table from a piece of 3/16" Lauan (it's good for everything!). Each molding took four very careful cuts. Some of the pieces didn't come out on account of the 2"x 4" from which they were made being warped and the resulting inconsistent width of the 3/4" square pieces into which it was cut.

I'd like the windows on the second floor to open, but I may skip that. The windows on the first floor will not open.

Lighting

Lighting will be done with white LEDs, perhaps sandblasted to diffuse the light, so it is radiated in all directions and not focussed in one direction. I suppose it depends on the particular installation.

Power (3v) will come from AA batteries under the floors. Wall sockets will be powered from the floor under them, and ceiling lights from the floor above them. I am hoping to use some standard-scale (1"=1') doll house sockets.

I may also use calculator batteries in free-standing lights - I bought a whole mess of calculator batteries on eBay for use in my laser pointer, and then promptly lost my laser pointer.

Fireplace

Silk flame exampleThe pièce de résistance will be a fireplace - with "flames" based on the flame lamps that are all the rage around Halloween. They are based on the illusion formed by a little scrap of silk flapping in the breeze of a fan while illuminated by red, yellow, or orange lights. The effect can be stunning. (Flame Lamp Image courtesy of Flaming Lamps LTD.)

I have ordered (from eBay) some really tiny (40mm square by 10mm thick) computer fans and will soon order some high-intensity LEDs. I am hoping that the fans will generate enough airflow, and that the silk will be flexible enough at this scale, to be realistic - if not, I may try Saran Wrap.

Right now I am trying to decide if I should install the fans under the floor underneath the fireplace, or in the chimney above it and duct the air under the fire. The latter would make it "portable".

Balustrades

The porch balustrade was a lot of fun to build, but it took forever. The design is based on the balustrades on our porches (we have one out back, too). They have flat balusters that imitate turned balusters.

Porch Balustrade
Porch Balustrade

I first designed a template, which I traced onto a 3/4" thick piece of pine (2"x 4" again), flipping it over to trace the other side. (That should have insured that each baluster was symmetrical, but they didn't quite come out that way.) Once I cut and sanded the piece to shape, I cut it into 1/8" thick slices to make six identical balusters. Pairs of 1/8" square strips were glued to 1/8" x 3/4" strips to form the top and bottom rails, into which the balusters were glued. The whole was then carefully squared and clamped to dry.

The balustrade will go between two 3/4" chamfered square columns that will support the portico roof, which is also the balcony on the second floor. While most of the doll house is modeled after our own house, our house actually lacks such a balcony. Oh well.

Further updates as progress is made!


Update 9/22/2003 - Functional Scale Wall Sockets

A great deal of research finally led me to the conclusion that it IS possible to build a functional, semi-accurate, 1/6th scale wall socket. It's not perfect, but it's pretty close.

Wall Socket Construction
Wall Socket Construction

First, I measured the distance between the prongs on a standard wall plug - one-half inch on center - and calculated what distance it would be at 1/6th scale - 0.0833 inches. The distance between the two sockets in the receptacle is 1.5 inches on center, or 1/4" at 1/6th scale. I figured that I could get away with using a spacing that is a factor of 0.1 inch, which is the standard spacing on what are called "PC Board Headers", those pins on your computer's motherboard into which you plug the ribbon cables. Such a socket would have 0.1 inch between the prongs and 0.3 inches between sockets, or 0.6 scale inches between the prongs, and 1.8 scale inches between the sockets. Close enough.

Female PC Board HeadersMale PC Board HeadersI bid on some male headers (right) on eBay. They're each 40 pins, so I'll cut one into twenty 2-pin plugs. Then I'll tear apart a ribbon cable that I've got sitting around, and cut the connectors (left) into sections four holes long and carefully rewire it so that all the connectors on each side were wired together. I'll probably remove the contacts in the middle four sockets, since they won't do anything but get in the way.

For faceplates, I drew one up in AutoCAD, modified to use the new dimensions, and scaled it to the right size. Each faceplate is 1/2" wide by 3/4" tall, and I printed 100 on a single page. Using an X-Acto knife, I'll carefully cut the holes in the faceplate, and a dollop of silicone will hold each faceplate to the socket. I'll probably stick a pair of plugs into the socket through the faceplate to hold the faceplate in place while the silicone sets. (I'll use silicone because it won't soak into the paper faceplate and wrinkle it.)

The auction for the headers ends soon - I can't wait to get them and start in!


Update 9/23/2003 - LED lighting

It has occurred to me that I'll run into polarity problems if I use LEDs and DC voltage for lighting - they won't light up if they're plugged in backwards. The answer - obviously - is to use AC. The LEDs will only conduct during the positive half of the cycle, but they'll flicker so fast that they'll seem to be continuous (I hope).

I'd like to use 12 volts, so I can power the tiny 12v fans I bought for the fireplace. However, the LEDs I want to use, Kingbright W7114PWC/H ([pdf, 70k]) or equivalent, can only handle 5 volts reverse voltage - 12 volts will destroy them. There are a few potential solutions to this problem, but the solution I like best is to use two identical LEDs wired in parallel, but each conducting in a different direction - the voltage drop across each LED is the only reverse voltage the other LED will see. This solution doubles the price (about $1 per LED), but also doubles the light the assembly will put out. A 120 ohm series resistor will drive each LED at an average of only 16 mA, well under the rated 20 mA - current will peak at 60 mA at the peak of the cycle, about twice the maximum continuous current but well under the maximum 100 mA peak forward current - and keep the voltage drop across each LED down to 4.9 volts.

I'll let you know how it works.


Update 9/24/2003 - Fireplace Foibles

I just realized how little wall space is available in the doll house - there is no room for a fireplace! Duh. I may have to design a free-standing wood or coal stove instead. Current plans involve a soup can.

I won the auction for the PC board headers, so any day now...


Update 9/26/2003 - LEDs

I bought some white LEDs on eBay - 100 for $20. These are NOT the Kingbright LEDs I had originaly thought I'd use - I don't know the manufacturer, but they're considerably cheaper and a lot easier to get. Here is how they compare:

Actual Kingbright
W7114PWC/H
Luminous Intensity 5000 mcd typical 4000 mcd typical
Viewing Angle 10° 20°
Max Reverse Voltage 5.0 v 5.0 v
DC Forward Voltage 3.3 v typical 3.7 v typical
DC Forward Current 20-30 mA 20-30 mA

They're 5000 mcd with a 10° viewing angle, whereas the Kingbright LEDs were 4000 mcd with a 20° viewing angle - what does that mean? Answering that question turned out to be a lot more complicated than I had expected, and I quickly had lumens, foot-candles, and steradians shooting out my ears. The results, when I translate my chicken-scratch notes into English, will be a new "Notes on LEDs" page on this site. [Done.] The long and short of it is that a 5000 mcd 10° LED is twenty percent brighter than a 4000 mcd 20° LED, but it only puts out about one-third as much light. They're brighter ... and dimmer. Go figure.


Update 10/1/2003 - Wall Sockets!

The PC board headers have arrived yesterday!

Functional 1/6th Scale Wall Socket
Functional 1/6th Scale Wall Socket
Ruler in background marked in tenths of inches

Boy, are they small.

I cut a 4-hole section off the ribbon cable connector by removing the pins in the fifth row and running my hacksaw blade through it. Turns out the kerf of the hacksaw blade is just about the same size as the pin holes, so the entire fifth row disappeared. Then I very carefully separated the first two wires from the ribbon with my X-Acto knife, and pulled the wires out of the second through and fourth row connectors to separate the socket from the rest of the ribbon cable.

Back of Functional 1/6th Scale Wall Socket
How the wires are connected

Looping the first-row wires around, I reconnected them to the fourth row so a single pair of wires will power both sockets. I could have, but didn't, pulled the connectors out of the second and third rows.

Lastly, I cut one of the above faceplates out of paper and glued it to the socket with a drop of Elmer's (I know, I said I'd use silicone), holding it in place with the two plugs.

Functional 1/6th Scale Wall Socket with Faceplate
With faceplate

Cool! This came out better than I expected. The faceplate is 0.50 inches wide by 0.75 inches tall. The socket itself is about 0.23 inches wide by 0.45 inches tall, and 0.33 inches front-to-back, including the spikes for the connectors. The plugs are 0.20 inches wide by 0.10 inches tall.

They will be surface-mounted in the dollhouse, just like most of the sockets in our house (build in the early 1860's before electricity was available, so no sockets were installed). I'll cut a 1/2" by 3/4" strip of wood and dado a 1/4" slot 0.60 inches deep in it, and cut it into 3/8" sections which I'll use as wall-mount electrical boxes. The wires will run out the open bottom into the floor.

In the mean time, I've been working on balustrades for the portico and balcony.


Update 10/20/2003 - First Light

The wall sockets work! I've finally gotten around to installing one and trying it out.

1/6th Scale Wall Socket powering a 3mm red LED
Powering a 3mm red LED

The wires go through the floor into the ceiling space of the floor below. The battery holder isn't installed yet, so I just held the wires up to a pair of button cells liberated from a Burger King toy. Since I don't have a plug soldered up yet, I just stuck the leads of a 3mm red LED (also from a BK toy) into the wall socket. Mom would be so proud...

Unfortunately, I discovered that pushing something long into the socket - like the leads of an LED - can push the wires off the connectors at the back of the socket, which is impossible to fix once the socket is glued in place. This wouldn't have happened if I had used the proper plug. Before I messed it up, though, the socket worked fine. Now I'm trying to decide how to get it off of there to fix it.

If I had made the walls thicker, 3/8" or so, I could have recessed the socket into the wall normally. Because the walls are only 3/16" thick, I couldn't do this, and had to opt for "surface mount" boxes. S'okay - most of the sockets in our house is surface mount.

I also completed and installed the portico, and painted the outside of the house Periwinkle Blue. I've been working on the painting the trim white, but it's slow going.

Portico
Portico

The white LEDs I bought on eBay haven't arrived yet! They're coming all the way from Hong Kong, so I don't know if I should worry yet. We'll see.

I'm looking for a cheap plastic chess set to cannibalize - I want the pawns to make chandeliers and the knights and maybe bishops to make desk lamps.

As an aside, the Notes on LEDs page is done.


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© 2003 W. E. Johns