Some days ago we build a laser gun with lego bricks and some electronic parts. We used a LED, a buzzer, a battery, a push-button and cables. Everybody in electronics told me, that it won't work if we would not solder it. The guy in the electronic store, my husband, my oldest son.
But this should have been something easy without massive amount of tools. I knew it would work. And it did. No soldering. There it is: Our first laser gun with sound. I think the design needs a revision, but we used six AA batteries so it needed to be big. Probably a 9 Volt would have done it. Next version.