Since starting in April, Ishaan Thakur, 14, and his sister Aanya, 9, have made nearly $160,000 mining cryptocurrency.
On their first day mining, the siblings made just $3. But in the last seven months, their operation has grown substantially. In October alone, Ishaan and Aanya made $64,000. It's become a lucrative business, which they've called Flifer Technologies.
"We have configured our computers to constantly scan for the most profitable coin and switch to that coin automatically," Ishaan tells CNBC Make It. "Ether is the dominant coin we mine, with bitcoin and ravencoin being the second and third."
Bitcoin is the largest cryptocurrency by market value. Ether is the second-largest and is native to the Ethereum blockchain. And ravencoin is an altcoin amid the top 100.
The siblings, who are based in Frisco, Texas, can process 15 to 16 billion ether algorithms per second, according to Ishaan.
"Even though we are now making a lot of money, we are just as proud now as we were when we only made $3 per day, since our main prize is not the money," Ishaan says. "My favorite part about our experience is that we learned about a new technology."
Ishaan and Aanya hope to continue to reinvest in their business, but also use the income to save for college.
Ishaan and Aanya first learned how to mine by watching videos on YouTube and searching the internet. But the process of mining is far from easy.
Mining rigs must compete to solve complex puzzles in order to validate cryptocurrency transactions. It's not only difficult, but it can be very expensive, as it requires a lot of computer power and energy.
The siblings have nearly 200 processors, which their father Manish Raj, a former investment banker, helped fund by taking out a loan. Raj declined to disclose the exact loan amount, but the worldwide shortage of computer chips made finding equipment much more difficult and set prices at a premium.
Ishaan and Aanya have around 100 Nvidia RTX 3090s, 50 of Nvidia RTX 3070Ti, a mix of Nvidia 30-series processors and 24 specialized bitcoin mining machines. Nvidia RTX 3090 graphics cards, for example, can cost around $2,500 to $3,000 each.
"We have additional cards on order, so we will be over 200 processors later this month," Ishaan says.
Ishaan built the majority of the computers, he says, which all run in parallel. "Because they are all concurrently processing the same job, my homemade computers can process more graphics transactions per second than NASA can," he says. "Many of my friends like to play games on their computers. Instead, I just like to build computers for fun."
Though their mining operation originated out of their home's garage, they've since moved to a data center in Dallas, Texas. It costs over $5,000 per month for the electricity bill and around $4,000 per month for technicians to monitor the rigs.
"Since our school has started, we don't have time to monitor our computers in the garage. So we put all the computers at a data center," Aanya says. "We use the garage only to build computers and then we send them to the data center. We have also hired technicians to monitor the computers because we have to go to school."
"We only mine in our free time," Ishaan says.
Ishaan and Aanya's parents, teachers and friends are impressed with their mining business.
"All of my friends read about our business on the internet," Aanya says. "My friends and teachers couldn't even believe it! The principal wrote my name in our school newsletter. It made me so proud."
"Our initial goal was just to save for college, but now we think we can do more," she adds.
For them, mining is "just the beginning," Ishaan says. The siblings plan to launch their own cryptocurrency later this year called Flifercoin. They've had developers and an attorney help out during the process.
"We think there are so many opportunities that involve crypto and we hope to be pioneers in this space," Ishaan says. "But I am just a 14-year-old, so my school work and saxophone take priority. Therefore, I am not able to work on my business as much as I would like to."