Im looking for shematics on how to connect ( and where to get ) 1 - 15 HERTZ speaker on picmicro 16F877. The program will generate 1-10 hertz but i must be sure that i have made correct hardware connections with the speaker.
btw. where to get such speaker ( for such low freq. ) ?
You can 'feel' such frequencies (commonly things like feeling your sternum pulsing), but you also have to be very careful. Some tones in this area, can cause nausea in quite a few people. Normally, an electrically controlled tuned Helmholtz resonator is used, rather than a traditional 'speaker', or a bass reflex system. Few standard transducers will go below perhaps 10-15Hz. Even ULF Sonar systems commonly stop at around 18Hz. Few transducers will be able to handle the 15:1 frequency range involved here (band pass cabinets etc., have a very limited range). The poster needs to find a transducer genuinely capable of handling this frequency range _first_. No traditional 'speaker' on the market will do so. Most will be active systems, with their own drivers, and this will effect the signal input required. Seriously, expect to be suprised at the price, and power requirements for such a transducer system. The lowest frequency normally 'aimed at' for reproduction in a ULF speaker system, is the 8Hz, representing the longest orgam pipe used in only the very largest organs (most only go down to 16Hz). Also expect to run into health and safety regulations at these frequencies. Since you cannot 'hear' them, and are unaware of the sound levels involved, regulations for ULF audio, are usually tight.
@Luhan Thank you for your suggestion about the chip but i have some 877 left from my last design.
@Roger Hamlett Everything that you have described is correct and i am aware of this. Im using this for medicine project and in the range of cca 35 cm. You are suggesting the transducer. Can you point me where i can get one ?
As you have written, i will have some problems with defining and "hearing" those freq. What are you suggesting, what should i do to define those freq. ( with hardware ) and is there some option how to see if those freq. are correct ?