This electronic bongo circuit will simulate authentic bongo sound when two touch plates are tapped.
Even though full scale synthesisers usually are hideously high-priced, it's possible to inexpensively generate single sounds, in this instance, bongos!
THE TOUCH plates might be created from any kind of electrically conductive material like copper, brass, stainless steel, aluminum, etc. Size and shape is not really essential they should be no less than 50 mm across however they might be a lot larger sized compared to it is preferred and round, square, triangular or whichever you might!
The finished unit could possibly be stored as you see fit in a box built into another instrument as well as constructed as a full size or miniature look-alike of a bongo drum.
But if you utilize a metal case you should possess the touch plates protected from the case and spaced away from any kind of metal surface by a minimum of 25 mm.
Potentiometers RV1 and RV3 are employed simply in the initial setting up process quick accessibility is not really necessary. Potentiometer RV2 regulates the level of sound output and it is needed if the unit is to drive an amplifier without any built in volume control.
If preferred this kind of potentiometer might be disregarded through the board and exchanged by a larger rotary potentiometer situated far from the circuit itself. If you undertake this you may need a 50k half watt rotary device (logarithmic curve).
Hook up it as if you were making use of the original potentiometer other than that now most likely performing it through three bits of wire
Setting up
Link the unit to a appropriate amplifier and loudspeaker. Connect the battery after which turn on the amplifier having the volume control at a lower setting.
Turn RV1 to minimum setting and RV2 to around mid way Transistor Q1 need to right now be oscillating and you should listen to a sound the loudspeaker. At this point turn RV1 until the oscillation simply stops and touch the connected touch plate momentarily.
This would trigger the circuit to generate a 'bong' sound which in turn decays aside. Continue to adjust RV1 till an authentic bongo sound is produced. At this time repeat the procedure for the second oscillator by adjusting RV3.
Turn the amplifier up loud and play away! The components particular may lead to frequencies of approximately 290 Hz and 400 Hz. Most of these frequencies tend to be dependant upon C1, C2 and C4 (for the left hand portion of the circuit) and also the corresponding C9, C10 and C11.
The frequency generated is inversely proportional to the values of such capacitors. Therefore doubling their value may have the 'bong' frequency.
In case you replace the frequency conserve the similar estimated ratios among capacitor values. In case you are innovative and/or possess some expertise in electronics it is extremely achievable to grant this circuit so that you will possess a whole series of oscillators of various frequencies.
The electronic Bongo circuit is completely symmetrical aside from the capacitor values stated earlier, so all you do to develop half circuits' all connected to the common battery along with their outputs attached to the point on the circuit which can be the junction of R8, R9 and R6.
Additionally it is likely to construct the circuit employing a range of switched capacitors to deliver the tonal range you might need.
How it Works
The electronic Bongo circuit comprises of two twin T kind sine wave oscillators. Each is practically equivalent you can find one per touch plate.
Each oscillator possesses a filter in the feedback loop. If the loop gain is more than unity the circuit will probably oscillate.
During this application the gain is adjusted to be simply lower than unity. Touching 'touch plate' force begins the oscillator however the moment one's finger is taken off the touch plate oscillations will probably stop functioning.
The rate of decay is obviously a performance of circuit gain which is directed by RV1 (and RV3).