Have you ever wanted a futuristic way to start a fire, or maybe just a cool desk toy that makes plasma? Have you wanted to start a winter fire in a way that does not involve an actual lighter with lighter fluid? Have you ever wanted a lighter that you never have to replace or refill? If so, then this is the perfect instructable for you. In this instructable, I will show you how to build an arc lighter from old recycled parts. It looks really professional and well made. The video below has a demonstration of the final product as well as a video tutorial to compliment this instructable. I will be building this as a Christmas present for my younger brother.
Lets get started.
Step 1: How It Works
This Arc Lighter lights fires with an electric arc. This arc can ignite paper because it essentially a stream of electrons flowing at a very high speed through a section of ionized air. These electrons, because of their high velocities, transfer a large amount of energy into the piece of paper placed in between the two electrodes. This energy causes the paper to ignite. Now, the potential difference between the two electrodes needs to be relatively high to overcome the breakdown voltage of air. This potential difference, or voltage needs to be at an upwards of 20,000 volts. This voltage is produced by an oscillator circuit and step up transformer.
The circuit starts with the 110 volt AC mains voltage. This voltage is then stepped down to 10 volts AC by a mains transformer. This voltage is then rectified and filtered to produce a clean 10 volts DC. This is then fed into the oscillator section of the circuit.
The oscillator uses a center tapped coil of 2 ohms, a transistor, and a resistor. The voltage initially comes in through the center tap. It proceeds to flow through the feedback coil, through the resistor, and into the base of the transistor. This makes the transistor start conducting current. It conducts the current through the primary coil to ground. This causes a rise in the magnetic field of the transformer's core. This rise in magnetic flux induces a current in the feedback coil opposite to the voltage flowing to the base. This shuts down the transistor and it stops conducting. After this, the magnetic flux in the core rapidly decreases causing current to flow into the transistor base once again. After this, the cycle repeats itself about 30000 times per second.
This rapid change of the magnetic flux in the core of the transformer induces a current in the high voltage secondary coil. Because of the high winding ratio of the secondary to primary coils, the voltage is significantly higher.
Now that you know how this circuit will work, its time to build it.
Step 2: Tools
For this project, the tools you will need will be:
- A drill
- A hot glue gun
- Wire Cutters
- Wire Strippers
- A Soldering Iron
- A Screwdriver
Step 3: Materials
For this project, you will need a few materials. A lot of these materials can be salvaged for very cheap. In fact, most of the parts used for this project were harvested from the back-light inverter of an LCD TV. This is a good way to make use of old circuit boards that would otherwise be thrown away.
You will need:
- 1 general purpose NPN transistor
- 1 5K resistor
- 1 100uF electrolytic capacitor
- 4 1n4001 diodes
- 1 High voltage transformer
- 1 10 volt mains transformer
- 1 pushbutton
- Screws, bolts, and nuts
- 1 main plug
- 1 heat sync
- heat shrink tubing
Step 4: Finding a Good Transformer
For my project, I will be using a back-light transformer form an LCD TV. It has 2 1 ohm primary coils and 1 1000 ohm secondary coil. This is very useful for the project I am doing. This will also work with a flyback transformer of a CRT TV. You will either have to wind your own primary coils or find the pins on the bottom corresponding to different coil impedance that work with this circuit. These transformers can be found in many different appliances.
Step 5: Soldering the Circuit
This step is relatively easy. You will need to follow my schematic closely while soldering. To build this circuit, you will need to first mount the transformer on a piece of perfboard. You can then add all the other components to the circuit board in the order that I placed them. Remember the direction of the primary windings! When adding the transistor, use ribbon cable to attach it to the board so it can be placed in positions that save space in the enclosure you are putting it in. Use solder to form traces on the back of the board. After the circuit board is done, it is time to make the enclosure.
Step 6: Preparing the Enclosure
For the enclosure of this arc lighter, I used a glossy black plastic box that I bought on eBay. You will need to drill holes in it corresponding to the holes on your mains transformer, button, and wires going in and out. You will need to use different drill bit sizes for the different holes. I made the enclosure upside down to make it easier to mount all the components. This means that the lid is facing the floor. You can then bolt on the transformer and tighten on the push-button.
Step 7: Wiring the Power Supply
To wire the power supply, you will need to attach the mains cord to the mains transformer. After that, you will need to solder the 10 volt AC wires from the transformer in series with the push-button. Make sure to use heat shrink tubing to secure and protect open solder joints.
Step 8: Gluing in the Electronics
After the box is prepared, you will need to glue in the high voltage transformer and the heat sync. I found the best glue for this step is hot glue. You can glue the different parts in whatever way works best for your enclosure. Make sure you leave room to access the holes. You can also hot glue the different cords coming in and out of the enclosure to reduce instability.
Step 9: Wiring the Electronics to the Enclosure
This step is relatively easy, you will need to solder the wires coming from the transformer and switch to the input section of the circuit board. Then, solder the output of the transformer to wires going out of the box. Make sure that everything matches the schematic.
Step 10: Making the Spark Gap
The spark gap of the arc lighter is what forms the electric arc. I made this using some wire, component leads, and a Popsicle stick. First, you need to find the output wires from your high voltage transformer. You will need to make these very short to prevent parasitic capacitance from lessening your voltage output(I learned this the hard way). You can then take the wires, and solder spare component leads to them. Make sure to use that heat shrink tubing! After that, bend and glue the output wires to a Popsicle stick. I spray painted the Popsicle stick to match the color scheme of the overall project(black and red). You can use multiple wood stick parts to create the angle of the spark gap that I did. This way looks really cool. You should now be done.
Step 11: It Works!
After plugging the arc lighter into a source of mains voltage (In my case an isolated variac), you can push the button, and you will see a purple arc of plasma jump in between the spark gap. To light things on fire, just put them in between the spark gap, and they should ignite instantly! This is a fun way to create fire without a lighter. It is also helpful to use when working with heat shrink tubing. I made this arc lighter for my younger brother for Christmas. He has always thought the projects I make are cool, but has never actually had one. By the way, he thought the arc lighter was awesome! It looks really nice with the red and black color scheme and works great!
Thanks for reading and good luck building!
Disclaimer: This project deals with high voltages and fire. It is dangerous. Use safely and responsibly. I am not responsible for any damages caused by the building of this device.