May 13, 2011: Today we tested our remote detonator. The purpose of the detonator is to destroy the balloon while it is still in viewing range to see if our parachute works. Would our payload descend gently back to Earth after the balloon pops? This is the question we must answer before ascending all the way to the stratosphere. High winds foiled our first attempt. The balloon was buffeted so badly, a wire tore loose from the detonator. Using a rope tether, we reeled the balloon back in and repaired the circuit. The winds calmed and we went aloft again. Would Friday the 13th be our lucky day? Play the video to see what happened!
May 12, 2011: Bill Robinson, super engineer and proprietor of Bishop's Radio Shack, has built a remote detonator for us based on a 555 timer. Here is the schematic. Once started, the timer counts down, closes a relay, and sends a 2A current through a model rocket ignitor. We can blast the balloon with an amateur rocket engine! The timer circuit allows us to select a delay between 45 seconds and 15 minutes--time to get the balloon aloft before it blows. The detonator is attached to the top of the parachute, pictured here.