Cryptocurrency is a fascinating subject, but getting into it now is pretty useless. The amount of mining power you need to profit from it doesn't cover the cost of the electricity you use. But, luckily a young man named Robert Piotrowski has come up with a way to mine cryptocurrency on Arduinos, Raspberry Pis, ESP8266 and ESP32, and even your laptop or old cell phone. And here is the best part: It uses a system called Kolka, which rewards lower power devices more than high speed processors, so mining on an Arduino is more profitable than on your high end laptop.

This opens the world of mining to everyone. I recommend checking out his site (https://duinocoin.com/) and see what it is all about. I really like experimenting with different setups to mine and I created a rig that uses 6 Tiny85 chips to do the calculations and a ESP8266 (D1) to get tasks and communicate the results to the network. The LEDs light every time one of the Tiny85s completes computational work for the network. It is an inexpensive and fun way to introduce you to mining.

The video shows the rig in action. An OLED display shows the connection status and the LEDs flash when work is completed. I mounted the board to a small stand, but you can use your creativity to display it.

This unassembled kit includes the PCB, sockets for the Tiny85s, and the discreet components (resistors, capacitors, LEDs). You need to supply and program the Tiny85s and the ESP8266. These can be obtained from Amazon and other sources (I have gotten my Tiny85s from eBay). Programming the Tiny85s requires a programmer and cannot just be programmed in the Arduino IDE, so please review how to do that and make sure you can program these chips before you purchase this kit. It also does not include the OLED display (this is an optional component as the miner will work without it.

For assembly, solder the components to the board according to the silkscreen. Watch the polarity on the chips. The resistors labeled RRx are the reset resistors and are 10k. The resistors labeled RLx are the LED dropping resistors. I include 220 ohm resistors, but you may want to lower that value of you want a brighter flash. Ensure the ESP8266-D1 you get has the same pinout as the one in the photo of the completed unit. This is a fairly standard layout, but I have seen some knock-offs with slightly different power pins. The Tiny85s are running at 3.3V but, amazingly, are clocked at 16MHz. This is because the Tiny85 has a fuse setting that allows the chip to run off of an internal PLL clock. That means no external crystal but 16MHz operation. This was news to me and part of the fun of development.