Firmware Developer for Secret Phone Calculator
Budget: £250 – £750 GBP
We’re seeking an experienced firmware developer to create custom firmware for a unique device that combines a fully functional calculator with hidden phone capabilities. The firmware must provide a seamless user experience, securely toggling between calculator and phone modes using a hidden button, while managing GSM communication, contact handling, and power efficiency.
---
✅ Device Functionality Requirements:
1. Calculator Mode:
Standard Arithmetic Operations: Addition, subtraction, multiplication, and division.
Display Management:
Results and operations displayed clearly on the OLED screen.
Proper handling of decimal points and multi-digit calculations.
Battery Efficiency: Ensure low power consumption during calculator-only mode.
2. Hidden Phone Mode:
Toggle Activation:
Pressing a hidden external button securely switches between calculator and phone modes.
No visible indicator during transition to maintain secrecy.
GSM Functionality:
Calls: Make and receive calls through the GSM module (e.g., SIM800/SIM900).
SMS: Send and receive SMS with clear OLED display prompts.
Contact Management:
Add, edit, and delete contacts stored in flash memory or SIM.
Display contacts on the OLED screen with navigation controls.
User Interface:
OLED displays menu options (Contacts, Call, SMS).
Intuitive navigation with button presses for selecting options.
Audio Management:
Hidden microphone and speaker integration.
Proper handling of call audio input/output with adjustable volume.
3. Power Management:
Low-Power Mode:
Efficient battery management to optimize standby time.
Automatically switch to low-power mode when idle.
SIM Management:
Seamless power cycling and SIM authentication upon boot.
Reliable reconnection to the network after losing signal.
---
?️ Technical Requirements:
Programming Languages: C/C++ or Embedded C.
Hardware Familiarity:
GSM modules (SIM800/SIM900 or equivalent).
OLED display handling and keypad interface.
State Management:
Smooth transitions between calculator and phone modes.
Reliable state retention when switching modes.
Power Efficiency:
Code optimized for minimal battery drain during idle states.
Error Handling & Stability:
Robust error handling to prevent crashes or freezing.
Stable performance across all features.
---
? Deliverables:
Fully Functional Firmware:
Complete firmware covering all functionalities as described.
Smooth, bug-free transition between calculator and phone modes.
Compiled Binary/Hex File:
Pre-compiled file ready for PCBWay to upload directly.
Source Code & Documentation:
Clear, well-documented source code for future updates.
Instructions on flashing the firmware.
Post-Delivery Support:
Basic support for integration and debugging during initial testing.
---
? Additional Clarifications for Developers:
Hardware Prototype: You will be provided with technical specs and documentation for the board.
Testing: If you require a hardware prototype for debugging, mention it in your proposal.
Budget: Please provide your fixed-price quote upfront based on the full scope outlined here.
---
✅ Device Functionality Requirements:
1. Calculator Mode:
Standard Arithmetic Operations: Addition, subtraction, multiplication, and division.
Display Management:
Results and operations displayed clearly on the OLED screen.
Proper handling of decimal points and multi-digit calculations.
Battery Efficiency: Ensure low power consumption during calculator-only mode.
2. Hidden Phone Mode:
Toggle Activation:
Pressing a hidden external button securely switches between calculator and phone modes.
No visible indicator during transition to maintain secrecy.
GSM Functionality:
Calls: Make and receive calls through the GSM module (e.g., SIM800/SIM900).
SMS: Send and receive SMS with clear OLED display prompts.
Contact Management:
Add, edit, and delete contacts stored in flash memory or SIM.
Display contacts on the OLED screen with navigation controls.
User Interface:
OLED displays menu options (Contacts, Call, SMS).
Intuitive navigation with button presses for selecting options.
Audio Management:
Hidden microphone and speaker integration.
Proper handling of call audio input/output with adjustable volume.
3. Power Management:
Low-Power Mode:
Efficient battery management to optimize standby time.
Automatically switch to low-power mode when idle.
SIM Management:
Seamless power cycling and SIM authentication upon boot.
Reliable reconnection to the network after losing signal.
---
?️ Technical Requirements:
Programming Languages: C/C++ or Embedded C.
Hardware Familiarity:
GSM modules (SIM800/SIM900 or equivalent).
OLED display handling and keypad interface.
State Management:
Smooth transitions between calculator and phone modes.
Reliable state retention when switching modes.
Power Efficiency:
Code optimized for minimal battery drain during idle states.
Error Handling & Stability:
Robust error handling to prevent crashes or freezing.
Stable performance across all features.
---
? Deliverables:
Fully Functional Firmware:
Complete firmware covering all functionalities as described.
Smooth, bug-free transition between calculator and phone modes.
Compiled Binary/Hex File:
Pre-compiled file ready for PCBWay to upload directly.
Source Code & Documentation:
Clear, well-documented source code for future updates.
Instructions on flashing the firmware.
Post-Delivery Support:
Basic support for integration and debugging during initial testing.
---
? Additional Clarifications for Developers:
Hardware Prototype: You will be provided with technical specs and documentation for the board.
Testing: If you require a hardware prototype for debugging, mention it in your proposal.
Budget: Please provide your fixed-price quote upfront based on the full scope outlined here.