---
id: task-2
title: Build One-Crystal Walkie-Talkie
status: To Do
assignee: []
created_date: '2026-01-05 23:03'
labels:
  - hardware
  - piezoelectric
  - electronics
dependencies: []
priority: medium
---

## Description

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Build the half-duplex walkie-talkie that uses a SINGLE piezo crystal as both microphone AND speaker. Press PTT to talk, release to listen - demonstrating the ultimate reversibility of piezoelectricity.

Key components:
- LM386 amplifier
- DPDT momentary switch (PTT)
- Single piezo disc per unit
- 9V battery power

Refer to piezoelectric-circuits-guide.md Build 4 section.
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## Acceptance Criteria
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- [ ] #1 Source LM386 chips and support components
- [ ] #2 Acquire DPDT momentary switches for PTT
- [ ] #3 Build amplifier circuit on breadboard/perfboard
- [ ] #4 Wire PTT switching logic
- [ ] #5 Build enclosures (Altoids tins work great)
- [ ] #6 Test two-unit communication
- [ ] #7 Add TX indicator LED
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