The $3 DIY Arduino
Save some cash by building a $3 minimal Arduino UNO clone from a bare ATmega328P chip — here's how to do it.
Doesn’t it seem like everything is getting more expensive? At this rate, electronics could soon become a hobby for those who consider a high-end GPU a reasonable alternative to a down payment on a house. Even one of the most basic tools for a beginning hobbyist — the Arduino UNO — is typically selling for north of $25 these days.
But Oliver Eybel wants us to know that our hobby can be much more affordable if we are willing to toss aside convenience and do a little more work for ourselves. To demonstrate this, he recently built a minimal Arduino UNO clone for about $3. No, it doesn’t have all of the circuitry of a real UNO, but it will get the job done in most cases and is compatible with all existing libraries.
The build is centered around a Microchip ATmega328P microcontroller, which is exactly the same chip you’ll find in an UNO. To get it up and running, the bare essentials are a 16 MHz crystal oscillator and a pair of capacitors for generating the clock signal, a pull-up resistor on the RESET pin, and a decoupling capacitor on the power pins. Power can then be supplied with any 5V supply that you have on hand. That’s all it takes.
One of the conveniences you’ll be missing is a USB-to-serial chip. This is used to program the ATmega328P, which doesn’t natively support USB communication. So to flash the chip with firmware, you’ll need to either use an external USB-to-serial chip (such as the FT232RL) or another Arduino board, which can do the job in a pinch.
This will get you most of the way there. However, bare ATmega328P chips that weren’t scavenged from an Arduino do not have the correct bootloader installed on them. This is needed to load firmware via UART, and also tells the chip to use an external oscillator. If you happen to have an ISP programmer, that will do the trick. If not, an Arduino can save the day again — it can do the work of a dedicated ISP programmer.
Going this route will cost you some time — especially initially as you get used to the new workflow — but it will also save you a lot of cash. It also reduces the size of an Arduino, which could come in handy for portable projects. Check out the video for more details on the build.