Voice-controlled bird circuit

The voice-controlled bird is a simulated electronic handicraft. Its appearance is the shape of one or two colorful birds perched on a branch. Under voice control or manual switch operation, the bird makes a pleasant chirping sound. At the same time, the bird's body will also make movements such as swinging and flapping its wings, which is very interesting. In fact, these functions are completed by the dedicated circuit in the base and the motor drive mechanism installed in the bird. The internal circuit of the voice-controlled bird has been mapped, as shown in the attached figure.

In the figure, the main device IC is a special integrated circuit (using black paste soft packaging. There are eight pins in total. Among them, pins ① and ④ are its working power input terminals. When the switch K installed on the base is pressed, the bird call program circuit stored in the IC will first output the audio signal from pins ⑤ and ⑥ of IC to the speaker (SPK) in a signal self-checking manner, and emit a pleasant bird call for about 20 seconds. At the same time, because there is another special circuit in the IC that can sample, amplify, shape and convert the signal, a "low-level" modulation signal is output from pins ② and ③ of IC to control transistors Q2 and Q3, so that the C poles of Q2 and Q3 output the driving signal to the two electrode sockets of "Bird A" and "Bird B". Then the driving voltage output by the socket is connected to the micro motor installed in the bird's body, thereby generating power; then through the transformation of the deceleration and action lever mechanism, the bird's head, wings and other parts are driven to move, producing very realistic effect movements.

When the chirping stops, the ② and ③ pins of IC become "high level" outputs, so Q2 and Q3 are cut off, and the bird no longer moves after the motor loses power.

After the first operation of this IC, it will enter a very low power consumption "static standby" state. If you want to trigger the IC again, you need to input a trigger pulse again at the "trigger" function end of IC7 pin.

At the ⑦ pin of Ic, BZ, R2, and Q1 form a control trigger (sound control mode) function circuit. The piezoelectric piece BZ is a sound sensing element. When BZ senses external sound, a weak induced voltage is generated on it. It is directly added to the b and e junctions of Q1, amplified by Q1, and a pulse is output to the ⑦ pin of Ic at the e pole of Q1, so that Ic is triggered and Ic works again. Let the bird's singing and bird's body movements reappear. R2 in this sound control circuit is used to set the control sensitivity of the sound control. If its resistance is too large, the sound control sensitivity will be low: if the resistance of R2 is too small, the circuit will be overly "sensitive", resulting in too much triggering, which will add noise.

Generally speaking, the failure rate of the voice-controlled bird in normal use is very low. Faults often occur over time, due to rust on the battery pole under the base or the "A, B bird" plug-in of the bird. This causes the failure to work. In this case, you can use sandpaper and other tools to clean it, remove the rust, and then restore normal operation.