Sport Rocketry

launch, makes the continuity check fail to show a complete circuit aer each launch, automatically silencing the buzzer and ex- tinguishing the READY TO LAUNCH in- dicator. Schematic Figuring out the wiring to accomplish the functions I wanted turned out to be a real brain bender for me. I have no for- mal training in electricity or electronics. I had to mentally work it out so that I had a launch sequence I liked. I'm giving you full access to my precious wiring schemat- ic (see Figure 5), but the schematic only makes sense if you know how the two key switches operate and how their contacts are laid out, as detailed below. I bought the two identical key switches from Mouser Electronics. e datasheet for the switches can be found on the mouser. com website by searching for the part num- ber below. ey were custom made to or- der, and here is the ordering information: Mouser Part #: 199-AS6H31KT2PG sition. A further turn to the right goes into the Right position, which is against spring tension (so letting go of the key will return it to the Center position). On the schematic, each cluster of six contacts represents a key switch. Each switch came with its six contacts labeled, including LC, RC, LNC, LNO, RNC, and RNO. On the top row of the schematic, for each switch we see Le Common (LC) and Right Common (RC). Below that, we see Le Normally Closed (LNC), Le Normal- ly Open (LNO), Right Normally Closed (RNC), and Right Normally Open (RNO). e small CR, L, LC, and R lettering on the schematic indicate the position of the key that "activates" that contact by supply- ing it with current from its correspond- ing Common. For instance, power is sup- plied to the LNC contact when the key is in the Center or the Right positions, but not while in the Le position. us, one click of the le-hand switch to the Center posi- tion sends current through the LEDs that illuminate the "Batteries Activated" (BA) callout. It also energizes the "Advance To Ready" (ATR) callout since power is car- ried over to the right-hand key switch, and the LNO contact on the right-hand switch is energized while the right-hand switch is in the Le position. ere are only connec- tions between the Common (first row) and the NC/NO (second row) contacts when the key is in the positions indicated by the small letters. Turning the right-hand switch to the Center position then deactivates "Advance To Ready" because the circuit that supplies those LEDs with current is broken when the right-hand key is moved to its Center position. With the le-hand switch in the Le position, there is no current supplied 32 MAY/JUNE 2024 SPORT ROCKETRY Manufacturer (IDEC) Part Number: AS6H-31KT2PG Description: IDEC Keylock Switches e key switches have three positions that correspond to the positions of the key aer insertion: Le, Center, and Right. e key can only be inserted and removed from the Le position. Turning the key to- wards the right clicks it into the Center po- Figure 4. How the rear holes of the case were cut. ree of the four holes have been completed using the router. Figure 5. Launch panel schematic. See explanation in article text.

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