Digital Stopwatch Design Using Discrete Logic – Urgent

I’m looking for an experienced digital electronics engineer to design and simulate a digital stopwatch using exclusively discrete logic, flip-flops, and logic gates.

**Technical Requirements:**
- Display format: MM:SS (00:00–59:59) using four 7-segment displays.
- NE555 astable clock generator (1 Hz) with LED indicator (±10% tolerance).
- Start, Stop, and Reset buttons with debouncing circuits.
- Four custom counters: seconds units (modulo 10), seconds tens (modulo 6), minutes units (modulo 10), and minutes tens (modulo 6).
- Correct carry propagation between counters.
- BCD-to-7-segment decoding.
- 5V DC power supply.

**Restrictions:**
- No Arduino, ESP32, PIC, or other microcontrollers.
- No integrated counter ICs (74LS90, 74LS393, etc.).
- All counting logic must be built using flip-flops and logic gates.

**Deliverables:**
- Complete circuit schematic and component list.
- Circuit simulation files demonstrating correct operation.
- Video recording showing the construction process and the stopwatch working correctly.
- Clear documentation of connections and logic.

**Important:** Physical delivery is NOT required. Components can be reused after recording. I only need the design, simulation, and video evidence of the actual prototype being built and working.

**Deadline: URGENT – The entire project must be completed today.**

Please apply only if you have solid practical experience with digital electronics and can meet the deadline.

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來源：Freelancer.com | 出價次數：9 | 剩餘時間：6 日 | 專案類型：按小時