Circuit Operation

Though the circuit may look complicated in this picture, it is actually very simple. The circuit is operated by magnetic reed switches that are in turn operated by rare earth magnets in the Planet Pucks. Each puck has three magnets:

1) Each puck has a 3/8” magnet located in the center.

2) Each puck has a 3/8” magnet located near the perimeter, but in a different spot for each puck.

3) Each puck has a 3/4” magnet located centerline at the bottom edge. (This magnet is for puck ejection and will be discussed later.)

Magnet #1 (the same for each puck) operates a reed switch in the center of any given slot that is connected in series with a reed switch in the center of the other seven slots. When all eight pucks are in place, these eight reed switches pick up a relay that provides power to the “Check Answer” button and to the indicator lights below each slot. This arrangement prevents the visitor from checking her answer until all the pucks are in place.

Magnet #2 is located along the upper perimeter of each puck in a location unique to that puck. This magnet determines whether or not the puck is in the correct slot. If a puck is in the wrong slot, this magnet will fail to align with the reed switch for that slot and nothing will happen. If the puck is in the correct slot, it will close the corresponding reed switch and energize a DPDT relay for that particular slot. (These relays are pictured above – eight of them – one for each planet.)

These DPDT relays serve two functions: 1) One pole of each relay is wired in series with the relays from the other seven slots. If all eight relays are energized, this indicates that not only are all the pucks in place, but that they are in the CORRECT place. This circuit energizes the “Correct!” light in the control panel and initiates the reset sequence, which will be discussed later. 2) The other pole determines whether the red or green light will be energized below each slot when the “Check Answer” button is pressed. The red lights are wired through the NC contact, and the green lights are wired through the NO contacts.

Here is a close up of the reed switches for Jupiter and Saturn (notice the “J” and “S”). As you can see, each slot gets two switches: one in the center and one in a unique location around the perimeter.