Build a super sensitive sound-activated relay switch with just one clap! 🎤💡 In this step-by-step soldering tutorial, we use an IC 555 in monostable mode to shape the trigger pulse, and a 7474 D flip‑flop for toggle‑action memory (clap on, clap off). You'll see how an electret microphone, BC547 transistors, a 5V relay, and a few passive components come together to control a 9V lamp. Perfect for DIY electronics enthusiasts who want to learn real‑world timer and flip‑flop applications. Watch the full build and test – then try it yourself!

🔧 Key components: 555, 7474, electret mic, BC547, 5V relay, 1N4733 Zener.
✅ No Arduino – pure analog/logic control.