Hardware emulating the Classic HP Calculators Build a fun, educational easy to build calculator. Features: All Through Hole parts. (easy to handle and solder) Runs about 4 to 5 times faster than the original (voyager series). Memory registers: same memory as the original. Continuous memory (Memory is not lost when calculator is turn off). Auto power off Runs on a single ATMEGA328 8 bit microcontroller running @ 8MHz (same as Arduino Uno) Speaker for audible keypress feedback 192x64 lcd display Display Backlight Has a real time clock. (Uses a 32.768KHz crystal) Uses a single CR2032 3V battery. Power consumption: 1µA off, 350µA idle, 3mA working (this is with speaker and backlight off) Can run any of the Voyager series and HP41C calculators, with the appropriate firmware. In programming mode, the names of the keys are displayed on the header of the display. It's a bit smaller than the original - 4.2" x 2.67" (10.668 x 6.7818 cm). More info at voyager. You will receive the following: Part QTY Value Description C1, C2 2 0.1µf Decoupling Capacitor C3 1 0.1µf Speaker impedance U1 1 ATMEGA328P Preprogrammed Microcontroller J1 1 6 pin female header SPI Programing header BAT 1 Battery Holder CR2032 Battery Holder SPK 1 BUZZER Speaker XTAL 1 Clock Crystal 32.768kHz Clock R1 1 10KΩ Reset pullup resistor R2 1 10Ω LCD backlight resistor BTN's 39 6x6mm tactile switch Key buttons, (11mm tall) RST 1 6x3.5 mm tactile button Reset button PCB 1 PCB PCB DISP 1 Display 192X64 LCD Display 1 9 pin male header For Mounting Display 1 double sided tape to attach display to microcontroller. 4 rubber feet rubber feet 1 Bumper 3D printed bumper 1 Bat Holder 3D printed Battery Holder 2 Panel Top and bottom panels 1 hardware Kit brass posts & screws Panels are made from standard FR-4 PCB. Top panel has ENIG finish. NOTES: Battery not included. To upload new firmware you will need a AVR SPI programmer. Such as the usbasp. And you will need to modify the cable, or purchase the AVR Programming adaptor. More info at voyager.