This is a breakout board for the Atmega328. It supports input voltage up to 16V, regulating down to 5V for the microcontroller. A bootloader can be loaded over ICSP and then the board can be powered and communicated with over an FTDI cable. All the input/output pins are broken out for prototyping.

We’ve made an open source AVR programmer that’s handy for putting a bootloader on a brand new board.

The Github repository has the manufacturing files. The project is released as open hardware under the CERN v1.2 Open Hardware license.

I’ve shared the project at OSH Park so you can buy a set of three bare boards for $13.35, or $4.45 per board.

The parts are available at Digikey. If this is your first time building a board, check out our assembly howto and remember to always buy a few extra of the capacitors and resistors. They’re very small, easy to lose, and often cost 30 cents for three but a dollar for 100.

Ref Qty Description Digikey PN
C2 C6 2 CAP CER 10UF 25V X7R 1210 587-2599-1-ND
C3 C4 2 CAP CER 22pF 100V C0G NP0 0603 399-11145-1-ND
C7 C8 C9 C1 C5 5 CAP CER 0.1UF 100V X7R 0603 490-3285-1-ND
D1 1 TVS DIODE 14VWM 23.2VC SMAJ14A-13-F SMA SMAJ14A-FDICT-ND
D2 D3 2 DIODE SCHOTTKY 20V 1A SMA SS12-E3/61TGICT-ND
F1 1 RESETTABLE FUSE 1.1A 25V MF-MSMF MF-MSMF110/24X-2CT-ND
J1 1 CONN TERM SCREW GREEN 2.54MM 2POS TH ED10561-ND
J2 1 HEADER MALE 6POS TH 1x06 0.1” 952-1902-ND
J3 1 HEADER MALE 6POS 2x3 0.1” 952-1921-ND
J4 J5 2 HEADER FEMALE 12POS TH 1x12 0.1” 952-1905-ND
JP1 1 SHUNT JUMPER 0.1IN BLACK GOLD 3M9580-ND
LED1 1 LED AMBER DIFFUSED 0603 SMD 475-2712-1-ND
R1 1 RES SMD 10K OHM 5% 1/8W 0805 311-10KARCT-ND
R2 1 RES SMD 220 OHM 5% 1/10W 0603 311-22GRCT-ND
S1 1 SWITCH TACTILE SPST-NO 0.05A 12V SW1020CT-ND
U1 1 IC REG LDO 5V 1.1A NCP1117 DPAK NCP1117DT50GOS-ND
U2 1 IC MCU 8BIT 32KB FLASH 32TQFP ATMEGA328P-AU-ND
X1 1 CRYSTAL 16MHz 18pF 40 OHM 4SMD CTX1206CT-ND