Anyone who has seen rays of sunlight shining through window blinds in the morning knows that the air in our homes can be quite dusty. Without anywhere for that dust to go, you’re likely breathing it in the entire time you’re at home. While that’s mostly harmless in many locations, it can be an irritant for people who have allergies. It can also be potentially dangerous in places with high levels of pollution. There is no substitute for a good air filter, but you can also build your own $10 ionizing air cleaner to help remove small particulates from your home.
An ionizer is an electric device which imparts a negative charge onto air molecules. Because they are negatively charged, the air molecules, along with the particulates they carry, will be attracted to positively charged surfaces. This lets you remove particulates from the air that are missed by your HVAC system’s air filter, or that are produced in your home by yourself and your pets. While there are many “ionizing air purifiers” on the market, they can get pretty expensive. Amaldev was able to build an ionizer for about $10, and thoroughly explains how you can, too.
A quick word of warning: ionizers require high voltages that can be potentially dangerous, and this device connects directly to mains voltage. Some people have also pointed out that this device may produce ozone, though it’s unclear whether that is actually true or not. You’ll need to decide for yourself if you want to take on that risk. If you do, the ionizer device is quite easy to build.
Ionization requires very little current, but it does need a high voltage. This design utilizes a series of Cockcroft-Walton voltage multipliers to produce that. Each multiplier is made with a pair of diodes and capacitors, and will double the original input voltage — minus a small loss from inefficiency. Because Amaldev is in Mumbai where mains voltage is 230V, he used 15 Cockcroft-Walton multipliers soldered to a custom PCB to end up with 6,900V. In the US, we’d need 29 multipliers to generate 6,960V.
On the output side of the device, a group of sewing needles have been soldered to a single output pad. The fine points of the needles help to ionize the air molecules. As you can see in the video that Amaldev posted to Instagram, this is able to very quickly collect incense smoke particulates in a sealed jar. The device also consumes very little power. In fact, the single indicator LED consumes far more power than the rest of the circuit. That means it should only add a few cents to your electricity bill per year, though you may want to also add a fan to circulate the air in your home through the ionization needles.