Category: Lower Extremity Disabilities

Bionic Boots

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Bionic Boots is designed for use by individuals will generalized weakness and strength in their lower extremities as a result of neurological involvement.

Important! Please note: This instructable is based on the author’s body size and weight. You will need to adjust to your body size and weight accordingly. When bolting pieces together keep the head of the bolt facing inwards and the shaft pointing away from the body. Also, should you decide to undertake this project, as with all major wearable items such as this, there is a risk. The author cannot be held responsible for any injury you may sustain as a result of this project. Before running, please try in a safe place with people to assist. They take a while to learn to use, even after making them, so take your time and test safely!

Technical Specifications: 

Step 1: Materials.
(6) Strong fabric strips (roughly 45 centimeters long)
(6) 3 centimeter x 22 centimeters steel strips
(2) 100 centimeters x 1.5 centimeters hot iron (or steel) – The author used 2 different sizes but is not vital to the project. 2 of the same will do just fine.
(2) Spring rated for roughly 1.3x your body weight. This will be covered in greater detail when installing the spring.
(2) Rubber bumper or feet, 1/3 of your foot size.
(2) Stainless steel (super strong) baking trays
(1) 100 centimeters x 1.5 centimeters x 1.5 centimeters U shaped Steel rod.
Rubber or foam matting, either 3 centimeters thick or 2 lots of 1.5 centimeters.
Joinery & tools:
Plenty of nuts and bolts, 4 or 5 millimeters work well
A drill and appropriate metal drill bits (mostly 4 or 5 millimeters for the bolts)
A pair of old boots in your shoe size (optional but fun)
Needle and thread
Flexible tape measure (for clothes works best)
Hacksaw or metal cutting saw (jigsaw etc.)

Step 2: Measuring and component making for the leg brace.
To save confusion regarding the measurements, the author used numbers where measurements should be used. As you progress, you'll fill see the number inserts. Starting from the top down, using the 100 x 1.5 centimeters pieces, measure out the circumference of the leg at just below the knee (1). Make sure it is slightly loose. Mark this out on your piece of metal and cut it out. Then using a vice and a hammer (or by hand) bend to an almost circular shape, leaving about 5 centimeters between the ends, to allow the foot to slip through comfortably and to go over the calf without catching. After this, take where you measured (1) and measure to just above the ankle. You will need 2 of these per boot. This is measurement (2). Cut these out from the same piece of metal, but bending is not necessary. Part (3) is just half of (1) bent to a semi-circle. For (4) measure around just above your ankle, and bend to a U-shape, with the two ends pointing the same direction as the foot. This will become clear when it is assembled.

Step 3: Assembling the leg brace.
Note: Using rivets or bolts at the top is optional. The author found rivets at the top worked adequately, making it more comfortable, however if vital bolts are used at the bottom, it helps to ensure that it is strongly set. Movement of the parts near the ankle must be avoided - that'll be covered in a later step. So now the components are all cut out and ready to go! Now with your drill, create a hole 2/3 of the way up of the sides of the brace, as well as one at the top and bottom of the sides. Then, drill holes through the other components: at the rear of the calf, one on each side. (see picture) Also, drill holes roughly 90 degrees from the two ends of both tops and bottom, so the side braces are opposite each other, and both openings of the two rings (top and bottom) both face the same direction. At this point, the brace should be ambidextrous, fitting on either leg. Trying the brace on as you go is ideal for making corrections but be aware of sharp pieces of metal. Pointy bits are the worst, they always seem to leave splinters. Ensure this fits comfortably on your leg, although expect some rubbing or tightness on your ankle. This is common and will be sorted when attaching the rest of the boot.

Step 4: Feet!
Now the brace is done, put that to one side. Take your baking tray and trace the shape of your foot, then mark about 3 centimeter of a border around your foot. Then, using a hacksaw (or if you're lucky a jigsaw), cut o around this outer line to create a panel for your foot. Then, using your favorite hammer, smack it to make a border to stop your foot slipping off, using your line around your foot as reference for when to stop. Needless to say, don't hammer it while your foot is still in there. If you do have a pair of old shoes or boots you want to use, now is the time to take a pair of scissors to them and remove the sole. Then, using a strong glue such as gorilla glue, attach them to the bottom of your metal soles. This isn't vital but it looks good, once finished up. The last part in this step is to start adding the connectors for our mechanism to sit on. Take the U-shape steel (100 x 1.5 x 1.5) and cut off an 11cm piece. Then, take your shoe and drill 2 10mm holes through the center of the heel, about 2 cm apart. pointing from heel to toe, so that you can then bolt the U shaped steel to the base, with about 6cm sticking out from the back of the heel. Don't bolt it down just yet.

Step 5: Ankle attachment.
Now it is time to attach the brace to the foot, so an ankle is required here. From my tests, the author found movement in the ankle will stop the from working as it is supposed to and increases risk of bones and muscles in your lower extremities. Take a 3 centimeter x 22 centimeter steel strip, and find the center. Drill a 10 millimeter hole though the opening, which will align with the 10 millimeter hole beneath, in the shoe. Then, measure the width of the foot. Cut it in half, bend the steel just under 90 degrees that distance from the drill hole on either side, making a "U" shape. Then, take the second piece of steel and bend it 90 degrees where the metal meets the heel, with the front meeting the front U shape. Drill a hole through the second piece to meet the underlying hole through the heel. Once this is done, you can bolt these pieces through the foot and to the U bar at the bottom. Ensure all of this is very well fastened (this does need to be done for both feet). Then, take the brace and attach to the top, drilling holes in the straighter parts of the ankles "U" shape and one in the rear will allow the strongest attachment.

Step 6: Strapping up.
Using the straps (i.e. material from old schoolbags), fastened it to the leg just below where the top ring sits, then loosened them just to the point where they met the brace, and marked it. Using some strips of fabric, sew it to both sides of the metal, keeping it in place on the brace. Repeat this step on the other side. You should then place your leg within the device and strap it firmly, reducing the movement between your leg and the brace. Repeat this just above the ankle for greater security.

Step 7: Reinforcing the brace.
By now it is mostly strong enough to hold a decent amount of weight but running as it is will cause the ankle to rotate, due to the T shaped join. Here, you get the third strip of steel and bridge from the ankle ring to the side of the brace, drilling holes through where they meet. Try and attach the straps just above your ankle strap, to stop it sliding upwards. This should now have totally stopped ankle and brace movement.

Step 8: Foot padding & strapping.
The penultimate core step is to take the rubber or foam matting and cut out a section (for 3 centimeters thick) the size of your foot. 2 sections are needed at 1.5 and 3 at 1 etc. This will allow you to stand on your shoe without the bolts at the bottom getting in the way. You will need to cut out small sections to allow the metal to pass through on the sides of the heel. It should slide in nicely and your foot can now rest on top with no ankle pain. You may find the ankle joint now sits above the ring, that's to be expected.
Next, take some more strips of fabric and a 2-part clip for each boot. Make sure it loops over your foot comfortably and can touch the bottom of the shoe, when your foot is flat.

Step 9: The mechanism.
Finally, the mechanism. This step was save for towards the end of the tutorial, because it is more difficult to make than the rest of the steps. The principle is as follows:
Weight is pushed down on the boot, which, using the brace, concentrates the mass to the heel and forward, evenly. The boot then pivots on the heel joining, which is connected to the bar. The resistance of the floor then causes the lever action to take place, pushing the energy only one way: to the spring. The spring stretches, meaning that the moment there is relief and pressure it will snap back forcing the lever to snap back to its original position. Thus, propelling the boot and user 45 degrees, with more energy than a standard muscle as a result of its potential energy in the tension of the spring. To make this work, take a small (2 centimeters) piece of the "U" steel and drill a hole through the center of all three sides. Then, drill a hole through the rear of the calf support (the semicircular section of the brace) and rivet them together. Then, take the spring. It should reach a few centimeters above the ankle ring and should be able to support 1.3 to 1.6x your body weight. Fine tuning can work within these parameters. If you are unsure of the strength, use a travel luggage weighing scale and pull till it stretches a little (minimum pull strength. This should work if it is close to your body. The author doubled the springs up, as they were too long, however shortening them does affect the strength. Next, once you are happy with the length and strength of your springs, take the remaining portion of your "U" shape steel. The author used a 34-centimeter long struts for the leg component, however that varies on your measurements. Drill holes 2 centimeters apart down the length of the strut through both sides of the U. Then, simply run a bolt across these two holes with the spring between (tighten using a nut but be careful to not crush the U). You may need to extend your heel piece, by drilling 4 holes through the U shape to stop the extension pivoting and connect a solid extension (The author used right angle brackets flattened by hammer, but they weren't the strongest. It is recommend using a stronger steel). Then you can run another bolt between the heel and another of the holes in the strut. This should complete the mechanism once tightly bolted, but not crushingly so. The author used rubber feet from a piece of old furniture at a car boot, drilled a hole and bolted the footplate in to place. This spreads the weight and the wider it is the less agile it will be but the steadier it'll be. If you feel unstable and there is no issue with the mechanism try increasing the surface area a little. Once this is bolted the boot should be complete. For comparison, the author’s boot was 14 centimeters off the floor when resting. The author also installed a small spring from the heel of the rubber foot to the strut to keep in in position for the next step. It is fairly weak but is recommended for running in.

Step 10: All done! and a few important notes.
This concludes the core part of the boots, all that remains now is to add aesthetics if you'd like and to learn to use your new booties. For aesthetics, the author highly recommend not putting anything but paint below the heel. Above that, avoid objects obstructing the moving parts. Other than that enjoy!


Price Check
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Additional Pricing Notes: 
Cost of supplies and materials.
Bionic Boots