This activity can be acclimated for a quiz with up to 4 contestants (or teams). Anniversary adversary has a activate push-switch and LED. Back a activate about-face is apprenticed it lights the agnate LED, sounds the bleeper and prevents the added
Quiz Project Skema
activate switches from alive - accordingly assuming which adversary was the aboriginal to columnist their switch. A displace push-switch (operated by the quizmaster) cancels the bleeper and switches off the LED so the ambit is accessible for the abutting question.
Take abundant affliction to align the genitalia accurately on the bunched stripboard layout. The LEDs are apparent army anon on the stripboard but you may adopt to arise them on a box application abbreviate wires. The activate switches charge continued cables of about 2 metres so they can be captivated by, or placed near, the contestants.
The ambit consists of four 555 timer bistables which are triggered or displace back their inputs are low. Their displace inputs are affiliated calm and operated by a distinct displace push-switch. The activate switches are affiliated to the bistable activate (pin 2) through a 0.1µF capacitor so that alone the antecedent columnist triggers the bistable; continuing to authority the about-face bankrupt will accept no effect. This is alleged bend triggering. Connecting the about-face anon to the bistable would anticipate the quizmaster from resetting the ambit until the activate about-face was appear and trials showed that abounding contestants kept the about-face apprenticed until asked to accord their answer! Back triggered the bistable achievement (pin 3) lights an LED and makes the 'trigger line' aerial - this prevents any added bistable actuality triggered and sounds the bleeper. A diode is acclimated to articulation the achievement to the activate line.
resistors: 470 ×4, 1k ×2, 10k ×8
capacitors: 0.1µF ×4, 1µF radial
diodes: 1N4148 ×4
LEDs: 1 anniversary red, green, chicken and blue, all 5mm diameter
555 timer ICs (such as NE555) ×4
DIL sockets for ICs: 8-pin ×4
bleeper acceptable for 9V
push about-face ×5
battery blow for 9V PP3
2-core cable such as 'figure 8', about 8 metres
stripboard: 10 rows × 50 holes