The recommended motor toy circuit which provides an automatic forward reverse actuation applying a sequential delay timer circuit is generally visualized in below diagram:
motor timer with reverse forward circuit for toys
Speaking about the above diagram, the T1, T2 stage in addition to the linked elements form an astable multivibtator with an oscillator frequency period equivalent to the required motor reverse forward timing period.
The TIP127 step is the latch circuit for permitting a push button start for the circuit.
The IC 4017 performs the forward and the backward pulses for the transistor driver step containing Q1-----Q4.
The transistor driver is connected as a H-bridge for aiding the reverse forward motion of the motor as a reaction to the activates get from the IC 4017 outputs.
The circuit could be noticed by using the following justification:
Any time the push button is pressed for a moment, T3 experiences a short ground pulse by way of the switch which generates the transistor turning it ON and offering a confident pulse to the circuit.
The initialization trigger leads to a logic low to occur at pin4 of the IC 4017 which holds and latches T3 into a powerful ON position despite the push button is developed.
During this time pin15 also obtains a positive pulse resetting the IC such that pin3 commences with a logic high.
With pin3 initially high actuates the H-bridge as well as the motor in a particular direction based upon the polarity of the motor wires across the bridge network.
Now T1 and T2 commence counting and the moment their set time lapses, pin14 experiences a triggering pulse from the collector of T2 which forces pin3 high logic to shift to pin2.
The above condition promptly reverts the H-bridge polarity and brings about the motor to begin an opposite course of its motion, until the following pulse at pin14 of the IC arises.
Whenever the subsequent pulse is imagined at pin14 of the IC 4017, the high logic at pin2 of the IC now moves a step ahead and settles at pin4 of the IC.
On the other hand seeing that pin4 is correlated with T3, a high at this pin quickly switches OFF T3, for that reason breaking the latch and switching OFF the power to the total circuit.
The toy motor circuit now totally switches OFF until the push button is pressed again.
A 0.1uF capacitor needs to be attached in equivalent with R2 with the intention that at any instance power is activated T2 activates ON first and permits a proper implementation of the system regarding the set time intervals.
The time intervals could be set or adjusted in accordance with user desire by altering the values of possibly R2/R3 or C1/C2 or these pairs.
Despite the fact that the circuit is executed as a toy here, it could gain numerous attractive industrial purposes which enables them to be modified for carrying out various user particular programmed machine activations.