@Organization: General DataComm, Middlebury CT @Message-ID: <26369@gdc.com> @Date: 30 Sep 91 11:05:41 GMT Interested Parties, I have received several email requests for further information concerning the ultrasonic ranging schematic. Please be aware (as I stated previously) that I have not as yet built or tested this schematic. However, I have reviewed (over and over again) and can not find any flaws in the design. Concerning the actual schematic being posted or emailed, the options as far as I can tell are either an ASCII representation of a schematic or possible a postscript file (can a Post script file be posted?). The last option would be to mail (thru US mail) the schematic to the interested party's. To those out there who are interested please let me know your preferance and/or other possible options and I will TRY my best. I spent a lot of time searching until I found this one so I'm willing to do what I can to help others. Now on to the fun stuff! The circuit uses a 10 MHz. Oscillater to generate 3 frequency's which are listed below: 39062 Hz - Used as the ultrasonic frequency. Since the base frequency of the transducers is 40 kHz with a range of +/- 2KHz this is an exceptable frequency. 6510 Hz - Is half the speed of sound - in inches, at sea level (13,030 inches/second). 2441 Hz - Used to ensure a long enough burst of 39 KHz. Tone is emitted for the receiver to Lock on to the signal. The Transmitter will, when triggered (in my application, from a micro) emit a 409us (16 cycle) burst of 39 KHz. This trigger will additional reset and hold a counter which will be clocked using the 6510 Hz. clock. At the end of the 409us period the 39 KHz. tone is shut off and the counter is allowed to start counting. This count is equivalent to one count per inch that the 39 KHz. will travel AND RETURN! This counter will continue to count until the receiver has detected the signal coming back. The Receiver, will amplify the signal and send it directly to a NE567 tone decoder chip. When the NE567 tone decoder detects the 39 KHz. tone being received it will halt the counter and (could) trigger an interrupt on the micro. This interrupt routine should read the counter and then retrigger the transmitter to start another cycle. TRANSMITTER CIRCUIT +5v +5v +5v | 16 | 14 |14 +-----+----+ +----+---+ +----+----+ | U2 |13 | 10 MHz |7 | P/O U1 |3 10| Q8+-------->39062 Hz. | OSC. +---------+ 4011 +o---------+>clk |12 | | 1/2| Nand | | Q9+-------->19581 Hz. +----+---+ +----+----+ 11| HC4040 |1 | 8 | +-----+rst Q12+--------> 2441 Hz. GND GND | | | | +-----+----+ | | 8 | GND | | RCV HOLD >-----------+ | |10 U3 | +----+----+ | 12| pre |9 | +5v ----+d q+----------+ 11| 74HC74 |8 RANGE STOP >----+>clk qn+-- | rst | +----+----+ |13 | | MICRO TRIGGER >------+ | +---------+ | 4| P/O U1 | 39062 Hz. >-------------------------------+ |6 | 5| 4011 +-----+ |4 U3 +----+ | | +----+----+ | | NAND | | +5v 2| pre |5 | +---------+ | | +---+d q+-----+----+ | X | 3| 74HC74 |6 | +------------------+ X 2.2k 2441 Hz. >------+>clk qn+-- | | X | | rst | | | c | | +----+----+ | | --------------------+ | | | | b| / | +--------+ | +----+< Q1 +----+----+ | | | \ T1 | XMT TRAN|< GND | 2N2222 |e +----+----+ | | | | +-------------------+ | | | gnd | | | +-------------------> COUNT START/STOP TRANSMITTER CIRCUIT (cont.) +5v. | +----------------+ 19581 Hz. >---+ +----------+------------+ | | | | | |4 | | +----------------+ | | +----+----+ | +-----------+ | |10 | | | 2| pre |5 | | | +----+----+ | | +---+d q+------+ | +---------+ | 12| pre |9 | | 3| 74HC74 |6 | | | 2| P/O U5 | +---+d q+-------------+>clk qn+--+ | +--+ | 11| 74HC74 |8 | | | rst | | 1| 74HC86 +--------+>clk qn+--+ | +----+----+ | +--+ |3 | rst | | U4 | | | | XOR | +----+----+ | | | | +---------+ U4 |13 | | | | +----------+------------+ | | | 6510 Hz. +--------------------------------------------------------------+ | | +5v | | | +-----+-----+ | 11 | | 9 | COUNT START/STOP >-----+rst q1+-------------* | | | 7 | | q2+-------------* | | | 6 * Outputs to | | q3+-------------* 8 bit read | U6 | | 5 latch ! | 74HC4040 | q4+-------------* | | | 3 | | q5+-------------* | | | 2 | | q6+-------------* | | | 4 | | q7+-------------* | | | 13 | | q8+-------------* | 6510 Hz. 10 | | 12 +-------------------------+>clk Q9+------------------> RANGE STOP | | +-----+-----+ | gnd RECEIVER CIRCUIT +------+ 1 meg | | v | +---XXXXXXX---+ | | | + | .47uf 10k | 2|\ | +-------||------XXXX---+---+ \ 6 | | 3| >------+--------+ +-----------+-+ +5v.---XXXX---+---+ / | >| RCV TRANS. | T2 10k | |/ U7 | +-----------+-+ X + LM741 | | 10k X OPAMP | gnd X | | | gnd | | +---------------------------------------------------------+ | +5v. | + | 4 | 10k 2|\ +---+---+ +-------XXXX-----+ \ 6 .47uf 3| N |8 10k 3| >-------||-----------+ E +---XXXX-> RCV HOLD +5v.--XXXX--+--+ / | 5 |5 10k | |/ U8 2.2uf 1| 6 +--------+------+ | + LM741 +----||----+ 7 | | | X OPAMP | | | 5k X<-----+ 10k X | 1.0uf 2| U9 |6 | X +----||----+ +--------+ | | | | | gnd | +---+---+ | | |7 | +-------+------+-----||-----+ | .01uf gnd NOTES: 1.) All unused inputs should be tied to GND or VCC. 2.) If standard CMOS components are used then 9vdc. can be used.