What does the project present?
Electronic generation of signals with given characteristics (synthesis) is a widespread process with multiple applications in science and technology. This electronic kit is also part of the category of electronic "synthesizers".
This DIY electronic kit synthesizes an electrical signal which, transformed into an acoustic signal by means of a loudspeaker, will have characteristics similar to dog barking, imitating it.
How does the assembly work?
The diagram includes three stable cells and a power amplifier, made with the T7 transistor that supplies power to the speaker with the generated signal. The steady rocker circuit (CBA) built with transistors T5, T6 generates a signal whose frequency corresponds to the "tone" of the bark.
Its operation is conditioned by the presence of voltage in the collector of transistor T4, so by the state of the stable tilting circuit made with transistors T3, T4. This astable is the one who commands the duration of a single "harness" and the break between "barks".
In order to obtain an even more pronounced resemblance to the barking of the dog, a CBA made with transistors T1, T2 was introduced. This CBA, which has a low frequency and dictates the duration of a "half" bark as well as the break between rounds.
- Vdc supply voltage - between 9V and 12V (batteries or DC voltage source)
- Current absorbed from Imax source - 200mA
- Speaker: impedance 3-16 Ohm; minimum power 0.25W
List of required components:
- T1, T2, T3, T4, T5, T6 - PNP transistors - AC180 - EFT 321 or BC557
- T7 - PNP transistor - AC180K or BC557
- C1, C2 - capacitors - 100uF (min. 12Vdc)
- C3 - capacitor - 4.7uF (min. 12Vdc)
- C4 - capacitor - 22uF (min. 12Vdc)
- C5, C6 - 0.1uF capacitors (min 12Vdc)
- C7 - 150uF capacitor (min. 12Vdc)
- R14 - 470 Ohm resistor (min. 0.25W)
- R10 - resistor 5.6 KOhm (min. 0.25W)
- R6, R8, R12 - 1.2 KOhm resistors (min. 0.25W)
- R3 - resistor - 12 KOhm (min. 0.25W)
- R5 - resistor - 15 KOhm (min. 0.25W)
- R7 - resistor - 18 KOhm (min. 0.25W)
- R2 - resistor - 22 KOhm (min. 0.25W)
- R9,11 - resistor - 20 KOhm (min. 0.25W)
- printed wiring or breadboard test board
- tin or connecting threads
Download the original IPRS leaflet Baneasa 7801
For a better understanding of the operation of the circuit we will need electronic scheme presented below:
In order to carry out this project in our own laboratory, we will also need printed wiring PCB layout From lower:
You can also see what it looks like below the original version made on printed wiring.
Many of you are probably wondering how this electronic kit was packaged or distributed. Well, to our surprise a Mister. Balauta Marius sent us a picture with the packaged product: