Tag Archives: Calculator

ATtiny84 powers this DUO Decimal SBC



Jack Eisenmann has created a number of Atmel-based homebrew computers that we’ve covered on Bits & Pieces, including the DUO tiny, DUO portable and DUO Mega.

Recently, Eisenmann debuted the DUO Decimal, an ATtiny84 based SBC.

“[This] ATTiny84 based computer [features a] 7 segment number display and 2 buttons. [You can] use the 512 bytes of EEPROM to store program code,” Eisenmann explained in a recent project post.

 “[Plus, you can] use the 512 bytes of SRAM for program data and as a code editing buffer.”

Additional key project components include:

  • 

(x1) 7 segment number display: LA-401VD (SC56-11EWA)
  • (x2) Button: 101-TS7311T1602-EV
  • (x3) 10K ohm resistor: 291-10K-RC
  • (x1) 20K ohm resistor: 291-20K-RC
  • (x1) 330 ohm resistor (7 isolated): 4114R-1-331LF
  • (x1) 14 pin chip socket: 2-641599-4 (1825093-3)
  • (x2) 3 pin male header: 69190-403
  • (optional) 5 pin female header: 929870-01-05-RA
  • (x1) Larger capacitor: UVR1H100MDD1TA
  • (x1) Battery holder: BAT-HLD-001
  • (x1) Battery: CR2032
  • (x1) Switch: MHSS1104
  • (x1) Board
  • (x1) Fuse for preserving EEPROM between programming cycles

As HackADay’s Adam Fabio points out, Eisenmann designed an entire language for the new board.

“DUO Decimal is programmed in an interpreted language called DUO Decimal Numeric Code (DDNC),” said Fabio.

”There are 47 DDNC commands, covering everything from basic math to list manipulation. Programs can be entered through the buttons, or save your fingertips by downloading them through the AVR ISP interface. The entire C code for the DUO Decimal, including the DDNC interpreter is available on Jack’s website.”

It should also be noted that Eisenmann coded several example DDNC programs, including 6 function calculator with trigonometry, a Mandelbrot set tester and even a version of the classic of the rock-paper-scissors game.

Interested in learning more? You can check out the project’s official page here.

Knock Knock: The Arduino-controlled calculator

Elementary school may be only a distant memory for some of us, but I’m almost certain I would have appreciated learning basic math on “Knock Knock,” an Arduino controlled calculator toy created by Switzerland designer Khalil Klouche.

“Knock Knock is a playful calculator designed for small children. Knock out a calculation on the wood surface and it will knock back with the answer,” Klouche explained in a homepage blog post.

“[Basic components used to build Knock Knock include a] wooden box, Arduino board, contact microphones and solenoids.”

According to Klouche, “Knock Knock” was designed for the exhibition “Touch!” at MUDAC (Museum of design and contemporary art) in Lausanne in 2012. It was subsequently featured at the Lift conference in 2013, on Nouvo on RTS (Swiss TV), and most recently, on the MakeZine blog.