Slide-timer
This circuit records commentary and music on one track of a tape while placing beeps that signal slide changes on another track. The gate U2a triggers U1, which is configured as a timer that generates a pulse each time it receives an input pulse, either from the tape input or via pushbutton switch S1. Timer U2 outputs one pulse for every input pulse received, regardless of how long S1 is pressed. The Q output of U2 at pin 1 is connected to U2b, which functions as an inverter. When pin 1 of U1 goes low, Q3 is activated, illuminating LED1. The Q output of U1 at pin 6 connects to the base of Q2 through resistor R5, allowing Q2 to turn on when pin 6 is high. When Q2 is activated, relay K1 is energized, sending a signal to the tape input through J2. The second set of K1 contacts triggers the projector. Power for the circuit is supplied by a 7805 voltage regulator, while the unregulated 12 V output from BR1 powers the relay. The 12-V relay requires two sets of contacts: one for advancing the projector and another for supplying beeps during recording. The LED indicates projector advancement. To record beeps, connect beeper jack J2 to the tape recorder input and the controller to the projector advance plug. The 60-Hz line frequency generates beeps, recorded on one half of the stereo tape, while the other track captures commentary. The beeper output is adjusted using a 500K potentiometer R6. Pushbutton switch S1 activates the beeps for tape recording, facilitating projector advancement. The beep length is automatic, and the projector advances with each press of S1. During presentations, one speaker should be disconnected from the recorder, connecting the recorder to the controller's jack and plugging it into the earphone jack. The controller should then be connected to the projector, ensuring that the beeps are inaudible and that the projector advances at the correct times.
The circuit design integrates several critical components to ensure proper functionality. The timer U1, configured to respond to input pulses, acts as the core of the timing mechanism, allowing for precise control over the recording process. The inverter U2b plays a crucial role in signal processing, ensuring that the activation of Q3 and LED1 occurs only when necessary, thus providing visual feedback on the projector's status.
The relay K1 is designed to handle the load required for both the tape input and the projector trigger, ensuring that the circuit can manage multiple functions without interference. The dual contact setup of K1 allows for simultaneous control over the tape recording and projector advancement, enabling seamless operation during presentations.
Power management is handled by the 7805 regulator, which ensures a stable 5V output for the logic components, while the 12V supply from BR1 is crucial for the relay's operation. This separation of power supplies helps to mitigate noise and potential interference between the analog and digital sections of the circuit.
The beeper output, controlled by the potentiometer R6, allows for fine-tuning of the beep volume, ensuring that it is appropriately audible during recordings without overwhelming the commentary track. The use of the 60-Hz line frequency for generating beeps provides a consistent and recognizable sound that can be easily synchronized with slide changes.
Overall, this circuit serves as an efficient tool for recording audio commentary and managing slide presentations, combining various electronic components to achieve a reliable and user-friendly operation.This circuit will record commentary and/ or music on one track of a tape and put the beeps that change the slides on another track. Gate U2a is used to trigger U1, which is configured as a timer when a pulse is received from either the tape input or via pushbutton switch Sl.
Timer U2 outputs one pulse for every input pulse received, no matter how long S1 is depressed. The Q output of U2 at pin 1 is fed to U2b, which is set up as an inverter. When pin 1 of U1 becomes low, Q3 is activated, lighting LEDl. The Q output of Ul at pin 6 is tied to the base of Q2, through R5, so that when pin 6 becomes high, Q2 is turned on. When Q2 is turned on, relay K1 is energized, and a signal is fed to the tape input through J2. The second set of contacts of K1 are used to trigger the projector. Power for the circuit is provided by a 7805 regulator. The unregulated 12 V output of BR1 is used to power the relay. The 12-V relay needs to have two sets of contacts as shown: to advance the projector, and to supply the beeps when recording.
The LED indicates projector advance. To record the beeps, connect beeper jackJ2 to the input of the tape recorder and connect the controller to the projector-advance plug. The 60-Hz line frequency is used to produce beeps that are recorded on half of the stereo tape. The other track is used for commentary. The beeper output is controlled via 500K!: l potentiometer R6. Use pushbutton switch S1 to put the beeps on tbe tape, where required, to adVl!Ilce tbe projector. The beep length is automatic, and tbe projector will advance once for every push of Sl. When presenting your program, disconnect one speaker from the recorder, and connect the recorder to the jack on tbe controller and plug into tbe earphone jack.
Connect tbe controller to the projector. The beeps will not be heard and the projector will advance at precisely the correct time.
The circuit design integrates several critical components to ensure proper functionality. The timer U1, configured to respond to input pulses, acts as the core of the timing mechanism, allowing for precise control over the recording process. The inverter U2b plays a crucial role in signal processing, ensuring that the activation of Q3 and LED1 occurs only when necessary, thus providing visual feedback on the projector's status.
The relay K1 is designed to handle the load required for both the tape input and the projector trigger, ensuring that the circuit can manage multiple functions without interference. The dual contact setup of K1 allows for simultaneous control over the tape recording and projector advancement, enabling seamless operation during presentations.
Power management is handled by the 7805 regulator, which ensures a stable 5V output for the logic components, while the 12V supply from BR1 is crucial for the relay's operation. This separation of power supplies helps to mitigate noise and potential interference between the analog and digital sections of the circuit.
The beeper output, controlled by the potentiometer R6, allows for fine-tuning of the beep volume, ensuring that it is appropriately audible during recordings without overwhelming the commentary track. The use of the 60-Hz line frequency for generating beeps provides a consistent and recognizable sound that can be easily synchronized with slide changes.
Overall, this circuit serves as an efficient tool for recording audio commentary and managing slide presentations, combining various electronic components to achieve a reliable and user-friendly operation.This circuit will record commentary and/ or music on one track of a tape and put the beeps that change the slides on another track. Gate U2a is used to trigger U1, which is configured as a timer when a pulse is received from either the tape input or via pushbutton switch Sl.
Timer U2 outputs one pulse for every input pulse received, no matter how long S1 is depressed. The Q output of U2 at pin 1 is fed to U2b, which is set up as an inverter. When pin 1 of U1 becomes low, Q3 is activated, lighting LEDl. The Q output of Ul at pin 6 is tied to the base of Q2, through R5, so that when pin 6 becomes high, Q2 is turned on. When Q2 is turned on, relay K1 is energized, and a signal is fed to the tape input through J2. The second set of contacts of K1 are used to trigger the projector. Power for the circuit is provided by a 7805 regulator. The unregulated 12 V output of BR1 is used to power the relay. The 12-V relay needs to have two sets of contacts as shown: to advance the projector, and to supply the beeps when recording.
The LED indicates projector advance. To record the beeps, connect beeper jackJ2 to the input of the tape recorder and connect the controller to the projector-advance plug. The 60-Hz line frequency is used to produce beeps that are recorded on half of the stereo tape. The other track is used for commentary. The beeper output is controlled via 500K!: l potentiometer R6. Use pushbutton switch S1 to put the beeps on tbe tape, where required, to adVl!Ilce tbe projector. The beep length is automatic, and tbe projector will advance once for every push of Sl. When presenting your program, disconnect one speaker from the recorder, and connect the recorder to the jack on tbe controller and plug into tbe earphone jack.
Connect tbe controller to the projector. The beeps will not be heard and the projector will advance at precisely the correct time.