Introduction: How to Make a Steampunk Corset

About: I love sewing, electronics, crafting and Chowder.

Estimated Cost: ~$30-$50 (more if you don't already own the necessary tools)
Estimated completion time: 10-15 hours
Difficulty: Moderate but accessible to newcomers

I have been making corsets for a few years now and I frequently receive emails from
people requesting tips and advice on how to get started. Also, I understand that depending
on their nature, corsets can be quite expensive and therefore not accessible to everyone.

I have spent considerable effort constructing a method for making a corset requiring the
least amount of technical knowledge, expensive tools and tedium I could manage. Even
so, there is still a lot of work involved. Please read the entire instructable before beginning.

If you have trouble seeing the details in any of the images click in on the little i in the top
left corner to view the image in its original format. Feel free to ask questions if something
is unclear or left out. The first image of each step is out of order so as to better illustrate
what that step entails in the thumbnails.

Also, please leave a comment with a photo of your finished work should you make your
own. I would love to see what people come up with!

UPDATE 8/11/2011: Corset pattern updated to include a better range of sizes and to allow for printing
on printers unable to print to the edge of 8x11 paper.

Step 1: Tools

Tools You Will Need:
  1. Straight-stitch sewing machine or hand sewing materials (Not for the faint of heart!)
    • For a sewing machine you will need a zipper foot
  2. Scissors 
  3. Awl
  4. Marking tool (Preferably something non-permanent like a chalk pencil)
  5. Fray Check (If you use a brocade or similar fabric with a tendency to fray)
  6. Lighter or other heat source (An iron works but may deposit residue)
  7. Grommet Setter 
  8. Pliers
  9. Ruler or seam gauge
  10. Dressmakers pins (Ones that won't snag on a sewing machine)
  11. Steam Iron
  12. Hole punch
  13. Pencil
  14. French Curve

Tools You Don't Need but May be Useful in Preserving Your Sanity:
  1. Rotary Cutter
    • Cutting Mat or other razor safe surface (office chair mats work great)
  2. Seam Ripper
  3. Weights (I make my own with bags full of steel shot)

Step 2: Selecting Materials

If you know where to look and are patient you can really save a lot of money on your
supplies. Please check the second to last page of this instructable for a list of resources and
tips for getting the best value out of your purchases.

PART 1: Selecting the Right Fabric (Figure 2-1)

Lining Fabric ~ (1) Yard: This is the structural layer of your corset. If your corset
were a house this layer would be the foundation. It must be very strong and have
minimal elasticity. This is the most important component in a corset! There is a
special fabric made especially for this purpose called coutil and it is the only thing
you should use for any corset you want to last more than a few hours. If you insist
on using another fabric, make sure it has the qualities I mentioned above and a
very tight (preferably herringbone) weave.

Fashion Fabric ~ (1) Yard: The fancier coutils are both expensive (+$30/yard) and
difficult to find, so this layer is employed to give you absolute freedom in creating
the look you want. Since this layer is for purely cosmetic purposes you can choose
from a great number of fabrics that would otherwise be unsuitable for corsets. For
a steampunk aesthetic I prefer brocades, faux leathers, course hemp fabrics,
and upholstery fabrics. This layer is what everyone is going to see, so be creative.

PART 2: Selecting the Right Bones (Figure 2-2 & 2-3)

I rarely use anything but a combination of spring steel and spiral steel in my
corsets. I mention the other types more as a cautionary tale then a recommendation.
You'll need to measure your completed pattern to know what lengths to purchase.
Bones come in pre-cut and continuous lengths. If you buy continuous lengths you will need
a bone cutting tool and a way to tip the sharp edges.

Spring Steel (white steel): This should be used in the front and back of the corset,
over the abdomen and the spine respectively. Spring steel has only one degree
of flexibility so it's perfect for maintaining the vertical lines around the busk and
lining up the grommets. Also, since it can't flex to the sides, it will more evenly
distribute pressure along its length than other boning types. The absence of this
quality would make the corset both uncomfortable and quite possibly a health

Spiral Steel: This should be used for all the bones between the spring steel ones
above. Spiral steel has two degrees of flexibility and can thus more elegantly and
comfortably conform to one's contours while maintaining the strength, elasticity
and durability of spring steel.

Plastic (featherlight): This is not a corset material despite what others might
suggest. It is often conveniently sold in its own bone casing for ease of
attachment. The problem with plastic is that it starts to get used to whatever shape
you bend it to. Before you know it, your corset that you put so much work into will no
longer properly conform to your contours and will have the very unattractive quality
of looking like a rack of lamb.

Rigilene: This product is great when I am designing a new pattern and want to
slap some bones in place quickly to see the effect they will have. But unless you
find the idea of corset lined with dozens in inward facing tiny spears that exhibit all
the negative qualities of plastic boning, avoid using this in anything you plan to wear.

Other: I have read numerous accounts of people making all kinds of strange and
exotic substitutions for bones. While there are probably artisans that can make
a fine corset boned with bamboo shoots I am not one of them. Here is a short list
of some suggestions I have found and all are completely unacceptable: long zip
ties, wooden skewers, braided rope, fiberglass rods, and the bottom portion of a
plastic hanger. Supposedly, the best material for corset boning is whale bone
(which isn't actually a bone) which was used extensively for quality corsets during
the Victorian era. For obvious legal and ethical reasons, whale bone is not an option.

PART 3: Selecting the Right Closure (Figure 2-3)

Busk Closure: The busk is a steel hook and loop mechanism at the front of the corset
that permits the corset to be put on and taken off with relative ease. There are two main
types, but for the purposes of this instructable we are only going to focus on the straight
busk (a.k.a. standard busk). The main disadvantage of the busk closure is the price.
Typically they range from $12-$18 depending on length and style. You'll need to
measure your completed pattern to know what lengths to purchase.

Laced Closure: The lace closure laces up the front identically to the lacing in the back.
This will significantly reduce the total cost of the corset, but the final product will take
much longer to put on and take off. The front lacing should not be used for tightening the

Eyelet Tape: This is a strip of fabric with grommets or eyelets already attached. I would
not recommend using this for your corset as it is not directly compatible with the method I am going
to show you. Also, eyelet tape is far less attractive than setting your own grommets.

PART 4: Selecting the Right Thread
Any thread will do so long as it is strong and feeds well through your sewing machine. For this
instructable I will be using my two favorites: Coats and Clark Dual Duty XP for the internal (hidden)
stitches and Gütermann Extra Strong Thread for the external (visible) ones.

PART 5: Selecting the Right Grommets(Figure 2-4)
Your local sewing supply or online retailer will most likely sell a kit that has the grommets, a hole
punch and a small anvil type or pliers type setting tool, generally for only a few dollars more then the
grommets alone.

I recommend size 00 (pronounced: double aught) two-piece grommets like the ones in the image.
Notice they come in many different finishes like brass, nickle, black and antique brass.

Step 3: Take Your Measurements

You will need the following three measurements to correctly form your pattern on the next step.
This step is easier and far more accurate with the help of a friend.

PART 1: UnderBust

Place the tape measure around the fullest part of your chest and back just below your bust.
For ladies this is just below the bottom edge of the underwire on a bra. No breath holding.
Figure 3-1.

PART 2: Waist

Tie a piece of stretchy string or elastic snugly around your waist then bend over at the hips.
Where the string rests when you stand straight again is your natural waist. Measure on the
string Figure 3-1.

PART 3: Underbust to Waist

Measure from your underbust  line to your waist line along your side under your arm
Figure 3-1.

Step 4: Adjusting the Pattern

PART 1: Print and Assemble the Pattern

Click the link below to open the PDF document containing the pattern:

Corset Pattern Link

Print a copy of the pattern. Make sure that your PDF viewer does not apply any form of
scaling when printing. Adobe Reader will most likely have "fit to printable area" selected by
default. In such a case switch the scaling option to "none". You may also need to increase
the color intensity setting on your printer or order to see the pattern more clearly.
The pattern is chopped up into 5 pieces so that it can be printed on standard 8.5" x 11"
paper. It will need to be assembled according to Figure 4-1. The column and row number
of each page is in the lower left hand corner.

In the corner of each page is a fraction of a circle with an x in the center. These need to be
aligned with their corresponding fragments on adjacent pages as shown in Figure 4-2. This will
be much easier if you put a source of illumination behind the pages. I made a light table from a
storage bin, a corner of my glass desk and a florescent lamp. A computer monitor set to a white
background works great too (be gentle though).

PART 2: Finding Your Pattern Size

Look at your three measurements you took in the previous step. Corsets are all about shaping
your figure so you are going to have to make a judgment call on just how much shaping you
want to do by reducing those measurements to some degree. Unless you are an experienced
corset wearer, please consider my recommendations below or else risk having a corset that is too
uncomfortable to wear. When fit correctly this pattern has a two inch gap between the laces.

Calculate the following:

Underbust(UB) = (underbust measurement from step three) - (1 inch)
Waist (W) =  (waist measurement from step three) - ( 2 or 3 inches)

Now use the table below to figure out which pattern size you need to cut out. If you are like
most people your underbust size and your waist size fall under two different pattern sizes,
in which case you will need to modify your pattern as demonstrated in the next part. All
measurements are in inches. If your size is in between two sizes use the smaller size.

Note: This is not the original size table or pattern. It has been updated to fix the inaccurate sizes.
My apologies to those who
were inconvenienced by this and no do

Size #          UB            W
1                  25.3          21.8
2                  27.7          24.2
3                  30.1          26.6
4                  32.5          29.0
5                  34.9          31.4  
6                  37.3          33.8 
7                  39.7          36.2

PART 3: Modifying Your Pattern

You will mostly likely need to modify your pattern in two dimensions. My mannequin has
an underbust-to-waist measurement of 3.5. This pattern was first made in her size and
then scaled to accommodate a range of sizes. Unfortunately, unless you have an
underbust-to-waist measurement of 3.5 inches you are going to have to extend your
pattern before proceeding.

Vertical Adjustment:
Consider Figure 4-3 and notice the two horizontal lines indicating the waist and underbust
lines. It is the vertical distance between these two lines that you will need to extend.
This will have to be repeated for each pattern piece.

The first step is to draw a vertical line running through, and perpendicular to, the waistline
and underbust lines Figure 4-4a.

Next cut the pattern in half at the waistline Figure 4-4b.

Place a black sheet of paper below your two halves and adjust them until the vertical
line you just drew is inline with the edge of a ruler. Slide the top half along the ruler
until the underbust line is a distance from your waistline equal to the underbust-to-waist
measurement you took in step three. Once you have everything positioned correctly
tape in place Figure 4-4c.

Horizontal Adjustment:
I will use the following example to illustrate the technique for adjusting the pattern
in the case that your underbust and waist measurement do not correspond to the
same pattern piece.

Say your underbust measurement is a size 3 and your waist a size 4. Mark
a dot at the intersection of the underbust line and the size 3 line and another at the
intersection of the waistline and the size 4 line.  Now use a french curve or similar
device to draw a curved line that smoothly transitions between these two points as
demonstrated in Figure 4-5.

Repeat these steps for each piece of the pattern and then cut them all out.

Step 5: Cutting and Preparing the Fabric

Part 1: Cut the Lining Fabric

Make sure the grain line of the fabric is parallel to the vertical lines on your pattern pieces
Figure 5-1. Cut two copies of each pattern piece from your coutil material Figure 5-2. You
will need to flip you pattern piece over for the second copy so you are creating a mirror image
of the first.

I like to use weights to pin my patterns in place while cutting. Not only is it much quicker than
pinning, it also keeps the fabric from shifting. The blue things you see in the images are zip-lock
bags, filled with about three pounds of steel shot, wrapped in duct tape.

Part 2: Transfer the Pattern Marking to the Lining Fabric

Transfer the markings on your pattern pieces to your coutil pieces Figure 5-3. You need not
transfer everything as I have. At the very least you should transfer the notches and the vertical
lines marked bones. The notches indicate which pieces will connect to each other.

Part 3: Cut the Fashion Fabric

Cut two copies of each pattern piece from your fashion fabricFigure 5-4. You will need to flip your
pattern piece over for the second copy so you are creating a mirror image of the first. If your
fashion fabric has a tendency to fray, apply Fray Check to the edges and let the pieces dry
before proceeding.

If you are using a patterned fabric take a moment to visualize how the panels will compliment
each other and plan your cutting accordingly. Consider Figure 5-5, there are depicted three
possible orientations for the front panels. The pair on the left looks relatively bland and
unbalanced. The middle pair don't compliment each other; one side is dominated flowers
and the other leaves. The pair on the right would be my choice.

Part 4: Baste the Fashion Fabric to the Lining fabric

Hand baste each fashion fabric piece to its complimentary coutil piece, wrong sides together
Figure 5-6. Machine baste along the long edges leaving around a 1/2 inch seam allowance.
Remove the hand basting and press the piece with a steam iron. Each pair can now be
treated as a single piece of fabric that is structurally suitable for corset making.

Part 5: Stitch the Bone Casing in the Front and Side Panels

Stitch a 3/8-inch wide bone casing centered on the vertical lines marked bone casing on the front
and side panels Figure 5-7. Use your exterior thread and set your machine to eight-stitches-per-
inch. I use the width of my presser foot to gauge the width of the bone casings. If you have a
dissimilar foot it might be necessary to pencil in a guide so your bone casings are straight and
even along their entire length.

Note: As the pocket formed by this will house one of your steel bones, the above method may not
be suitable for all fabrics. The bones will work their way through a light fabric or at the very least
create unsightly stretch marks. If you are using a lighter fabric for your fashion layer create an
internal bone casing using a strip of 3/4 inch twill tape as shown in Figure 5-8.

Your front and side panels should now look similar to Figure 5-9.

Step 6: Sewing the Panels Together

Part 1: Join the Panels

Pin the Left-Back and Left-Side-Back panels together (right side facing in) along the edges
bearing identical notches. Set your machine to 12-stitches-per-inch and sew together using 
your internal thread, leaving a 5/8 inch seam allowance Figure 6-1.

Note: On the previous page I recommended a seam allowance of 1/2 inch for the machine
baste to join the pieces, yet in Figure 6-1 I used about a quarter inch so that the 
basting and the actual structural seam won't get confused.

Add the Left-Side, Left-Front-Side, and Left-Front panels in a similar manner Figure 6-2.

Repeat for the right half of the corset.

Part 2: Top Stitch

Switch to your external thread and set your machine to eight-stitches-per-inch. Fold the seam 
allowance between the Left-Front panel and the Left-Front-Side panel inward toward the side
panel and top stitch in place along the edge of the seam (approx. 1/16 inch from seam)
Figure 6-3 & 6-5.

Repeat for the remaining seams, making sure that all seam allowances are directed inward
as in Figure 6-4.

Your corset should now look similar to Figure 6-6.

Step 7: Adding a Busk

Part 1: Mark Loop Side Placement

Center the loop side of your busk on the wrong side of your Left-Front panel, approximately 5/8
inch from the edge. Mark the location of the loops as shown in Figure 7-1. Mark lines
perpendicular to the termination points of the previous markings as shown in Figure 7-2.

Part 2: Stitch Loop Side Pockets

Set your machine to 12-stitches-per-inch and use your internal thread. Pin the Left-Front-
Facing (right side facing in) to left front panel you just marked.

Please watch the embedded video below before beginning.

Stitch a seam 5/8 inch from the edge, skipping over the pockets you marked in Part 1.
You will notice that I start the seam at the midpoint between each pocket, back-stitch
until I reach the top end, forward-stitch to the bottom end and then back-stitch again until
returning to the starting point. This is very important. If you terminate your seam too close
to the pocket the busk will slowly work its loose when worn.

Part 3: Insert Loop Side of Busk and Stitch into Place

Fold open the seam allowance you just created and insert the loop side of your busk. Pay
attention to its orientation. You want the side with the raised loops facing away from your
body when you are wearing it. See Figure 7-3.

Fold the front facing over the busk as shown in Figure 7-4.

Set your machine to eight-stitches-per-inch and attach your zipper foot. Using your external
thread, stitch 5/8 inch from the edge, catching the front facing and trapping the busk in place
Figure 7-5.

Part 4: Attach Front Facing

Pin the Right-Front-Facing to the right front panel (right sides facing in). Set your machine to
12-stitches-per-inch and stitch a seam with your internal thread 5/8 inch from the edge.
Figure 7-6.

Part 5: Mark Placement of Hook Side

Fold over the Right-Front-Facing and align with the left half of the corset. Insert pins into the
hook side, centered vertical between loops (horizontal position is irrelevant) Figure 7-7 & 7-8.

Mark sure your pins are secure and lift off the loop side of the busk. Flip the hook side over and
mark a horizontal line perpendicular to the seam where each pin pokes through Figure 7-9.

Measure the distance from the forward edge of the hook side of your busk to the center of
a hook Figure 7-10.

Place a vertical mark on the lines you previously created, at a distance from the seam equal
to what you just measured on the busk Figure 7-11.

Part 6: Insert Hook Side and Stitch into Place

Press an awl through the intersection of the marks you made in the previous step. Ideally you
do not want to break the fabric fibers. Instead, you merely spread the fibers enough that the
hooks of the busk can pass through, allowing for the hole to close up cleanly around the base
of the hook Figure 7-12.

Insert the busk hooks through the holes Figure 7-13.

Fold the facing over and sew in place with a zipper foot and your external thread as you did
in part 3 above for the loop side of the busk.

Your corset should now look similar to Figure 7-14.

Step 8: Adding the Rest of the Bone Casings

Part 1: Stitch Back Panel Bone Casings

Set your machine to 12-stitches-per-inch and use your internal thread. Pin the Left-Back-Facing 
to the Left-Back (right sides facing in) along the notched edge. Stitch together leaving a 5/8
inch seam allowance. Repeat for the right side. Figure 8-1

Set your machine to 8-stitches-per-inch and use your external thread. Fold back facing over
and edge stitch.

Stitch 5/8 inch in from the edge stitching being sure to catch the back facing.

Stitch 1/2 inch in from the previous line being sure to catch the back facing.

Stitch 3/8 inch in from the previous line being sure to catch the back facing.

See Figure 8-2.

Part 2: Stitch Seam Bone Casings

Set your machine to eight-stitches-per-inch and use your external thread. Stitch 3/8 inch from
the top stitches you made in step six such that you catch the remainder of the seam allowances
and form sleeves for your bones to be inserted into Figure 8-3.

Your corset should now look similar to Figure 8-4.

Step 9: Finishing the Top Edge

Part 1: Construct Edge Pattern

Click the link below to open the PDF document containing the edge pattern:

Edge Pattern Link

Print out a copy of the edge pattern (beware of scaling) and cut out the pieces. Set the small
strip aside for now. Measure the length of the top edge of one half of your corset. Combine
the large strips to give you a length equal to what you just measured plus two inches.
Figure 9-1

Part 2: Cut Edge Pieces

Cut out two copies of the edge pattern from your fashion fabric at a 45 degree angle with
the fabric grain Figure 9-2. Cutting the fabric like this allows it to conform to the contours
of the upper edge of your corset without the fabric bunching.

Part 3: Attach Edges

Machine baste the edge pieces centered and flush with the top edge of each corset half
Figure 9-3.

Set your machine to twelve-stitches-per-inch and use your internal thread. Fold the overhanging
edges inward and stitch a seam 3/8 inch from the top edge Figure 9-4.

Fold over the edge and hand baste in place as in Figure 9-5.

Top stitch inside the edge seam using twelve-stitches-per-inch and a thread that blends well
with the fashion fabric layer Figure 9-6. Make sure to catch the back side of the edging. Remove
the basting.

Your corset should now look like Figure 9-7.

Step 10: Inserting Bones and Finishing Bottom Edge

Part 1: Measure the Length of the Bone Casing

Measure the length of each bone casing indicated with a dot in Figure 10-1. Measure from
the top edge casing seam to the bottom edge of the corset as in Figure 10-2. The
appropriate bone length is this measurement minus 3/4 inch. The subtraction is needed to
both leave a clear path for your bottom edge casing and to give the bone enough room to
slide a tiny bit.

Part 2: Insert Bones

Order or cut bones to the lengths measured above. Make sure you use the appropriate type
of bone as diagrammed in Figure 10-1.

Insert the bones in the bone casings being sure to sandwich them between the layers of the
coutil where possible Figure 10-3. This will reduce the likelihood that a bone will poke through
and reduce its prominence on the exterior.

Part 3: Finish Bottom Edge

Note: Be sure that the bones are fully inserted or you'll be snapping a lot of needles.

Machine baste along the bottom edge catching all layers.

Repeat step 9 to finish the bottom edge of the corset.

Your Corset should now look like Figure 10-4.

Step 11: Inserting Grommets and Making the Laces

Part 1: Mark the Grommet Placement on the Corset

Find the small strip of paper you cut out and set aside in step 9. Center it on the gap
between the two spring steel bones on the back of the corset and mark each interval
with a chalk pen of similar marking tool Figure 11-1.

Part 2: Punch Holes for Grommets

Punch holes at the center of the horizontal marks you made in part one Figure 11-2. The size
of the holes will depend on the size of your grommets. I recommend size 00.

Use a small amount of Fray Check on the rims of the holes, especially if you are using a 
fabric that frays easily.

Part 3: Insert Grommets

Insert and set a grommet in each of the holes. Your corset should now appear similar
to Figure 11-3.

Part 4: Make the Laces

It is easy to find pre-cut and tipped laces online. I recommend a length of six yards. In a
pinch you could probably find a suitable set of shoe laces or use a length of sturdy
(i.e. grosgrain) ribbon.

Watch the video below to see how you can make your own using a spool of lacing and
some heat shrink tubing Figure 11-4.

Note: If you don't evenly heat the tubing it may pull to one side. If you roll the tube between
your hands while it is still soft you can straighten in out. This it what I am doing in the
last few seconds of the video.

SWV1787 suggested this great link to a site demonstrating eight different ways to create
aglets (the tip of the lace).

Part 5: Lacing the Corset

Find the center of your lacing and tie a small knot. This knot will prevent the lacing from 
"walking" each time you lace and unlace your corset.

Lace your corset like I have shown in Figure 11-5. You most likely lace your shoes in a
similar fashion. There are other methods of lacing a corset but for health and comfort I
recommend the method I have shown for any "real" corset.

The most common argument I get against this advice is that cross lacing allows you to
cinch the corset all the way closed.You should never lace a properly fitthing real boned
corset all the way closed.

When laced a corset is placing a lot of pressure on your bones and internal
organs. If you leave at least a two inch gap (as this pattern in designed to do) in the
lacing, the laces can redistribute pressure to make it uniform along the length of the
corset. If you leave no gap in the lacing then your body is now forced to conform to the
corset instead of the other way around.

You can observe this on your shoes. Lace up your shoes and notice how the gap in the laces
change in shape after you have worn them for an hour.

Part 6: Finished

Your corset in now finished and should look similar to the final image!

Thank you for reading my instructable. I hope you found it a useful starting point for making
your first corset. Please let me know if you find anything that can be improved.

If you want to learn more about corset making I recommend picking up a copy of The Basics of
Corset Building
by Linda Sparks.

If you're confident in your abilities, additional patterns can be found free online in the Victorian
era Dutch publication De Gracieuse

Step 12: Resources

Below I have listed my favorite suppliers and resources as well as a short review of what they have to offer.


Vogue Fabrics- Great prices on busks, steel boning and grommets. They also have a
nice fabric selection with some hard to find items.

Fashion Fabric Club - You could spend days searching through their fabric selection. I
recommend signing up for their news letter and holding out for one of their frequent sales
or special offers. Be warned though, they have some of the worst customer service I have
ever encountered.

Joann's Fabrics - Huge selection. It seems like they have a 40-50% off one item coupon in
their mailer (available online)  just about every month. Also if you are looking for brass snaps and
d-rings to spice up your corset checkout the purse making hardware on the opposite side of the store
where you can find them for a fraction of the price of comparable items in the sewing notions section.

Hobby Lobby - Small selection of fabric, but prices are pretty competitive and they also have a
40% off coupon they mail out pretty frequently.

Quilting Warehouse - The best selection and price for thread I know of. They have some items that are hard to find elsewhere like metal tipped laces and
fancy coutil but I try not to buy here unless I am placing a large order, as their minimum shipping option
is ~$16 regardless of size and weight.

DIY Upholstery Supply - Great selection of faux leather. Excellent customer service and free swatches.

Hemp Traders - Dozens of great hemp fabrics for creating a tough and rugged aesthetic. If you want a good
source of inspiration order a scrap bundle or swatch book. I love this place.

LillysWorkshop on deviantART - If you are interested in seeing any of my other steampunk and fantasy
corset designs please check out my deviantART gallery.

3rd Epilog Challenge

Finalist in the
3rd Epilog Challenge

Halloween Epic Costumes Challenge

Participated in the
Halloween Epic Costumes Challenge

SINGER Quilting Contest

Participated in the
SINGER Quilting Contest

MakerBot Challenge

Participated in the
MakerBot Challenge