How to make a hammer of Thor or Mjolnir

Homemade Thor's Hammer

For those of you who like superhero comics, or are simply fond of Nordic mythology, in this tutorial we bring you the steps to ‘build your own Thor’s hammer’. Although you may know him from Mjolnir. If you have free time and you want to do DIY, you can create your own hammer with some “magic” features that will bring us the use of free hardware to implement, for example, magnetic attraction.

The truth is that there are several ways to do it, also several materials to work with, and even several diagrams of the circuitry or hardware that we will implement to have different functions for our home hammer. You already know that DIY is free, that you can introduce your own modifications in front of what we show you here, and that the limit is your imagination…


Ideas

As I mentioned in the previous paragraph, there are many ways to do this, as you can customize your Thor’s hammer to your liking. Here I’ll give you some ideas to modify it and then I’ll show you the steps to create a prototype base you can build on:

Materials

You can use various materials to create the hammer, depending on what you like to work with most or what tools and resources you have. The material is not a limitation, since you can do it with almost anything. Here are some suggestions:

  • Recycled materials: you can use wooden or plastic boxes with an appropriate size for what is going to be the head of the hammer. It should be a little hollow so that you can later house the circuitry inside and camouflage it so that it is not seen. As for the handle, you can use a cut-out mop or broom stick, and even the mast of old tools (better something hollow or that you can easily hollow out to carry wiring inside). Also keep in mind that if the surface can be worked easily, so much the better. I don’t only mean painting, since there are materials to which paint doesn’t adhere well, but also if they accept being carved, cut, etc.
  • Wood: wood is a cheap material that can be worked very well, for example to create the angular profiles of the faces of the hammer’s head and even make the carvings that the original Thor’s hammer has. It can be glued with glue or other glues that we can easily find in hardware stores. As for the handle, perhaps the wood is not the best, since a hollow wooden tube of these dimensions could be unsound …
  • Polymers: plastic is also a cheap and easy to work with material. We can use a lot of adhesives to join all the parts. Some even allow heat treatment to mold the parts. You can also use PVC pipes of the right thickness to make the handle. Obviously, both wood, plastic and other materials would need extra treatments such as paint, leather coating, etc.
    3D printing: if you have a 3D printer, it will be a very good idea to use the grey plastic base color for the hammer head and generate a faithful computer generated replica of the hammer and let the 3D printer do all the work. Keep in mind that the head should be detachable so that you can insert the electronics inside, so don’t make it out of one piece.
  • Metal: if you have the opportunity to work with metal, although it is not the safest material, you could also do it. For example, with welded plates to make the head, and devise some mechanism to leave a door to be able to introduce and access the electronics in case you need some adjustment or repair. The handle can be any metal tube …
  • Paper mache: not the most solid option of all, but one of the cheapest. You can use a box or brick as a mold and cover it with layers of paper (e.g.: newspapers) and glue diluted in water. Layer by layer it will take consistency until it leaves a more or less hard structure. Remember that what you use as a mold will have to be removed from the interior, do not close it completely… Also, one of the faces would have to be uncovered temporarily to introduce the circuitry.
  • Mix: you can also use different types of material for each of the parts of the hammer…

Circuitry:

As with the materials, we will also give you some ideas to create your electronic mechanism to customize the hammer:

  • Magnetism: creating magnetism can be very simple, you can build an electromagnet and insert it into the hollow head of the hammer. Another idea is to introduce inside neodymium magnets to generate that attraction in an even simpler way, and let the circuit do other things explicitly.
  • Make it work only with you: if you want, you can add a module for Arduino like a fingerprint reader so that it only works with your fingerprint, and thus make it “obey” only you as it happens with Thor’s hammer in fiction.
  • Sound: you might think that you could use some sound as a sound effect when you move the hammer or when it hits some surface. Maybe you could record or extract certain sounds from Thor’s movies and leave them recorded in some memory and play them back through a small speaker inside the hammer. You can use sensors that detect when you move the hammer so that, by means of an Arduino sketch, they begin to be emitted.
  • All combined…

And as a basis for creating your prototype, you can read on in the following sections…

Build the structure of the Mjolnir or Thor’s hammer:

Now let’s go to the step-by-step guide to build what will be the carcass and structure, that is, the exterior of our hammer. You can take it step by step or use it simply as a guide to make your modification based on the ideas we have proposed or on your own:

Step 1 (research and materials):

Thor's hammer: replica

Use Google or other sources such as Thor’s hammer to get a reference of what you should build. Even, if you find it more comfortable, you can use this same image that we show you here. This gives you an idea of the materials and finishes you need to use.

In addition we must prepare everything we need:

  • Wood
  • Hollow metal tube
  • Glues (wood, fabric, metal)
  • Tools for cutting and carving wood (saw, sandpaper, sergeants, drill,…).
  • Primer, metallic grey spray paint, bitumen

Step 2 (build the hammer head):

Once you have the reference, we get to work building the hammer head. For example, we have based ourselves on the wooden model. To do this:

  1. Get the wooden planks. It should be a wood of at least 1 cm thick so that it allows us to make the milling and different reductions.
  2. Measure, draw the lines and cut (image 1) the faces of the hammer head. The dimensions of the prism should be 15.25×15.25×23 cm, that is, 15.15 cm wide and 23 cm at its long end. Keep in mind, that some parts will mount over the others when you glue it, so you should leave the thickness of the wood boards as extra when measuring the width to cut the pieces properly.
  3. Glue the four sides (image 2) with the dimensions mentioned above. You can use any special wood glue or glue. Put pressure on the parts while the glue dries or use clamps or sergeants to keep it from moving.
  4. While gluing, you can make the two covers for the hammer faces (picture 3). To do this, we must make a pyramid shape as shown in the images. Cut a square with the appropriate width to cover both sides of the hammer head that is being glued, then draw a pencil box 1 or 1.5 cm smaller in the center of that piece. We can use a tilted wood saw to cut the flanks with a little inclination (from the face where we have drawn the lines to the other side of the piece reaching its outer edge) or use a wood router and go wearing the wood to generate such a shape.
  5. Now we can paste one of the faces with glue, but we must leave the other still without glue to introduce the electronics inside.
  6. Once all the block is dry and we have respected the time of pasting, we can make a small cut or grimace in the area where you will join the head with the hammer handle as shown in image 3, and just in its center drill the hole to insert the handle with a drill bit with the width of the handle we will use (see Step 4 – Point 1). By the way, to make the recess, you can use a wood brush or a sander to eat a little bit of the wood in the center.
  7. With the same power sander or hand sander, we can round the peaks of each corner to leave a smoother shape as shown in the imaǵenes.

Step 3 (details and engravings):

We continue now with the details of the hammer head:

  1. We can decorate the hammer head (image 1) in many ways. One can be by hand carving if you know how to treat the wood, with a punch. Another simpler way for those who are not so handy is to use hot glue or silicone to make some “garavatos” on a small plate of any material you have at your disposal. This plate should have the same dimensions as the sloping side that we did in point 6 º of the previous section.
  2. This plate will serve as a mold (image 2) for our decoration. Then we can pour some polymer that hardens on it so that the marks are on the piece. For example, we can use a stick that has two colors and we can knead it to mix them and make it hard, after pressing it against the mold so that the marks are engraved.
  3. Once we have the ornament, you can cut out the leftovers to leave it square. And finally we stick it with some glue to the edges (image 3).

Step 4 (put the mast):

To put the handle or mast of the hammer:

  1. Use a metal tube, such as the typical hollow tubes for hangers or curtains that you can find on any DIY surface.
  2. Insert the tube into the hole you previously made in the hammer head. Previously you should have smeared some strong glue on the edges of the hole so that the wood and the metal join well. Wait for the glue to dry and it will be ready.

By the way, the hole is only made on one side of the head, it should not go through, because if it goes inside the head, it will make it difficult to insert the electronics and will not leave space.

Step 5 (finishing):

The next step is to paint our hammer and put the layer of skin for the mango:

  1. First you must sand the wood to remove any splinters or imperfections and leave the surface smooth to apply the paint. Do it with a very fine grain sandpaper. Clean with a humid cloth all the surface to remove the dust.
  2. Apply a base or primer so the paint can adhere in a better way and prepare the surface so it is not so porous and the finish is of more quality.
  3. Then, once it has dried, start to paint the whole surface of the head. It is best to use metallic spray paint, spray gun or airbrush, because with a brush you can notice the brushstrokes in the finish.
  4. Once the paint has dried well, we can make different finishes to give more realism. For example, use bitumen all over the surface and then remove it with a cotton cloth before it dries. That will make the bitumen to embed in the nooks and crannies of the surface, like the engraving we did before and the feeling that it is old metal. Another idea I give you is to use gold paint to make some reflections on the gray surface. You can do it by slightly wetting the tip of a brush and giving some brushstrokes grazing the surface. There are also other finishes such as rust, etc., you could use.
  5. Finally, we will use an imitation of leather or brown synthetic leather to cut a long strip of about 2 cm wide and go rolling over the surface of the handle. Use a special fabric glue on one side of the fabric to make it stick well. You can use a cut out of this same fabric to stick it on the tip in the shape of a handle .

Create the internal circuitry:

We have already finished our Thor’s hammer, or rather, our replica. There are many people who already leave it like that, but if you want some electronic DIY, and since we are a hardware blog, we must start creating the circuitry. But first, you must gather these materials:

  • Arduino Pro Mini 5v and FTDI cable to program the board.
  • Sparkfun fingerprint scanner. It is also necessary the JST connector
  • TTP223 capacitive touch fingerprint sensor. Adafruit also has alternatives.
  • Optocoupler 4N35, together with a 1K resistor.
  • 3.7v 150mAh lithium battery to power the capacitive sensor. Or you can avoid it if you don’t connect the handle to Arduino’s ground.
  • 4 AA battery holders, and of course 4 12v 1.2Ah SLA batteries.
  • Crydom CMX60D10 60v 10A solid state relay.
  • 1n400x diodes, such as 1n4002, 1n4007, etc. It is worth any of them.
  • Homemade electromagnet. It can be easily built with a metal core and a copper wire coil or you can buy it .

Now that we know the parts, let’s see how to connect them all to create our circuit, and for that, what better than a diagram:

Circuit diagram with Arduino for Thor's hammer

In the Fritzing program there are not all kinds of components that will be used for the project, therefore, some of the components that appear are representing others. I recommend that you install Fritzing and look for all the components that appear in the diagram to better clarify how they are connected. Anyway I would like to make these clarifications:

  • Notice that we have some AAA batteries that are representing where the 12v battery we are going to use would go.
  • The antenna shown above in the diagram is not really an antenna, it is representing the metal tube from the hammer’s hand to which we will have to connect one of the wires.
  • What appears as a flash memory module for Arduino is actually the fingerprint scanner.
  • The selenoid at the bottom of the diagram, with the resistor tapping its terminals, is actually the electromagnet.
  • We also see the small solid state relay, even though it’s for AC instead of DC, but just so you know, we can represent it with the parts we have in Fritzing…
  • There is a small Op-Amp located on the left that actually represents the capacitive fingerprint sensor and that we will have to take out of the handle, in an accessible place to put our fingerprint.
  • Actually, there is also a cable connecting the ground of the capacitive sensor to the metal core or electromagnet core. This is not shown in the diagram, but remember that you must do this. That provides the path to ground when the hammer.
  • Remember that if you don’t connect the control to ground (GND), you can avoid using power from the capacitive sensor and optocoupler, and save that.
  • You can also add interruptions between the power and the arduino board in case you want to turn off the circuit and not have it always connected .

As for the sketch that we must record in Arduino to program our circuit, it will be (don’t forget the FPS library):


/*
Martilo de Thor Project
*/

#include "FPS_GT511C3.h"
#include "SoftwareSerial.h"

FPS_GT511C3 fps(4, 5);

int touch = 0;
int capPin = 9;
int flag = 0;

void setup() {
Serial.begin(9600);
// fps.UseSerialDebug = true; // so you can see the messages in the serial debug screen
fps.Open();
pinMode(10, OUTPUT);
digitalWrite(10, LOW);
pinMode(capPin, INPUT_PULLUP);
}

void loop() {
touch = digitalRead(capPin);
//Serial.println(touch);
if ((touch == 0) && flag == 0) {
digitalWrite(10, HIGH);
fps.SetLED(true);
if (fps.IsPressFinger()) {
fps.CaptureFinger(false);
int id = fps.Identify1_N();
if (id<200) { //Don't care which fingerprint matches, just as long as there is a match
digitalWrite(10, LOW);
fps.SetLED(false);
flag = 1;
}
}

}
else {
fps.SetLED(false);
digitalWrite(10, LOW);
}
if ((touch == 1) && flag == 1) { //Reset the flag after the hammer has been lifted to return to normal behavior
flag = 0;
}
}

Once you have assembled your circuit, you must manage to introduce it all inside the wooden head that we prepared in previous steps. Close the other lid on the face that we didn’t close at first and you’ll be ready. Enjoy!

Sources:

Instructables – Mjolnir (Thor’s Hammer)

Instructables – Thor’s Hammer – Mjölnir

Instructables – Electromagnetic Mjolnir (From Thor’s Hammer Prank)

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