CANADUINO Arduino Pocket Calculator DIY Kit

CANADUINO Arduino Pocket Calculator DIY KitThe Arduino Pocket Calculator DIY Kit by CANADUINO combines a vintage 10-digit 5×5 LED matrix display with an ATmega328P microcontroller to create a functional educational tool. The kit includes pre-assembled surface-mount components and requires through-hole component assembly by the customer. Pre-loaded firmware provides immediate functionality, while complete source code enables customization and learning.A 3D printed enclosure and its design file (.STL) are also available.Arithmetic OperationsBasic operations: Addition, subtraction, multiplication, divisionAdvanced functions: Square root, reciprocal (1/x)Floating point support with up to 6 decimal placesSigned number support (positive and negative values)Operation chaining (sequential calculations without clearing)Error handling for division by zero and mathematical errorsNumber System ModesDecimal Mode: Standard base-10 calculations with floating point supportHexadecimal Mode: Base-16 display and input (0-9, A-F)Binary Mode: Base-2 display and input (0-1)Real-time conversion between number systemsHexadecimal letter entry via long-press key detection (500ms threshold)Display Characteristics10-digit capacityRight-aligned numerical displayOverflow detection and indicationSeven adjustable brightness levels (6% to 100%, adjustable in source code)Custom startup message (modifiable in source code)Technical SpecificationsModel: ATmega328P-PUClock: 8MHz internal oscillatorOperating voltage: 4.0V - 5.5VProgramming interface: ICSP header (pre-installed)DisplayModel: SCD55100A (Osram/Siemens)Configuration: 10 digits, 5×5 LED dot matrix per digitColor: RedInterface: 3-wire serial + resetBrightness levels: 7 programmable settingsInput Interface24-key tactile button matrixConfiguration: 6 rows × 4 columnsScanning method: Software matrix scanning with debounceLong-press detection: 500ms threshold for special functionsPower SystemPower source: 3× AA batteries (not included)Nominal voltage: 4.5VOperating range: 4.0V - 5.5VPower switch: Slide switch includedPCB SpecificationsPre-assembled SMD components (large 1206 package for easy troubleshooting/modding)Through-hole component assembly requiredICSP programming header installedPower ConsumptionCurrent draw varies with display brightness setting:Default operation (40% brightness): approximately 60mALow power mode (20% brightness): approximately 40mAMaximum brightness (100%): approximately 150mAMinimum brightness (6%): approximately 20mABattery Life Estimates (2500mAh AA batteries):Continuous operation at 40% brightness: approximately 40 hoursContinuous operation at 20% brightness: approximately 60 hoursTypical intermittent use: several weeks to monthsComponents Requiring AssemblyATmega328P-PU microcontroller (pre-programmed)SCD55100A LED display module24 tactile push buttonsPower slide switch3× AA battery holder with wire leads - watch polarity!!2 DIP28 IC sockets (optional use)Digital ResourcesArduino source code V1.6 with comprehensive comments (download)SCD55100A display library (download)SCD55100A library documentation (download)3D printer STL file for enclosure (download)Schematic diagram (download)!! Not Included !!3× AA batteries (alkaline recommended)3D printed enclosure (available HERE)Assembly RequirementsSkill Level: Beginner to intermediate soldering experience recommendedAssembly ProcessSolder 24 tactile buttons to PCBInstall power switchInstall LED display (direct solder or socket)Install microcontroller (direct solder or socket)Attach battery holder wire leads: red to [+] and black to [-]Install batteries and test functionalityOptional: Install in 3D printed enclosureNote on IC Sockets:Two DIP28 sockets are included for component removal convenience. However, direct soldering is recommended for permanent installations. IC sockets can develop contact resistance issues over time, affecting reliability.Complete calculator logic:

• Matrix keypad scanning with debounce
• Long-press detection for hexadecimal letters
• Display optimization for minimal current consumption
• Base conversion algorithms
• Error handling and overflow detection

Arduino source code with educational comments explaining:

• Keypad matrix scanning implementation
• State machine architecture
• Number base conversion algorithms
• Display multiplexing and optimization
• Long-press detection logic
• Memory management strategies

Code Customization Options (examples):

• Adjust display brightness levels
• Modify startup message
• Add mathematical functions
• Implement additional number bases
• Customize key mappings
• Add memory storage functions

3D Printed Enclosure

• A professional enclosure design is available for download in STL format.

Educational Value / Learning Objectives:

• Understanding embedded programming concepts
• Binary, hexadecimal, and decimal number systems
• Through-hole soldering techniques
• Matrix keyboard scanning algorithms
• Display multiplexing and control
• State machine implementation
• Firmware development and debugging

Arduino Library for SCD55100A display:

• We developed an easy to use library that is available for download.

Warranty and SupportThe provided firmware and source code are offered for educational purposes without warranty. The code may contain errors or bugs. Users are encouraged to review, understand, and modify the code as needed. Software updates and corrections will be made available as issues are identified.The Arduino Pocket Calculator DIY Kit Includes:1 x PCB assembly with pre-installed SMD components1 x ATmega328P-PU (pre-programmed)1 x SCD55100A LED display24 x Tactile push buttons1 x Power slide switch1 x Battery holder (3× AA)2 x DIP28 IC sockets4 x Mounting screws