| ??? 09/29/09 13:52 Read: times |
#169255 - Ultrasonic Measuremnt |
Hi, I am development an ultrasonic measurement device with ATMEL AT89C51RC2. I am using MURATA´s MA40A3S (sender) y MA40A3R (receiver), both working in 40 khz. Tx circuit is working fine, but the problem is the rx circuit. I have been looking for ultrasonic rx circuits and I have found that almost all of them are based on the same idea:
-2 or more amplification stages -rectifier (envelop detector) -voltage comparator I am using this circuit: http://www.8052.com/users/juan_alv8052/Rx1.doc The two opamps stages are working fine. I see the 40 Khz echo. I forgot to tell you that I am running the tx sensor with a 50% duty cycle square train pulse (6 pulses) of 40 khz. The trouble is at the output of D2. I don´t see any signal. Can you help me? Until I don´t solve this problem, I am stuck. I can´t continue with the code because I need the hardware to test it. Thank you in advance Best regards Please sorry for my bad English... |
| Topic | Author | Date |
| Ultrasonic Measuremnt | 01/01/70 00:00 | |
| Don't you need a load for D2? | 01/01/70 00:00 | |
| You wont see much across D2 | 01/01/70 00:00 | |
| LM339 input bias current | 01/01/70 00:00 | |
| Bias Voltage + diode? | 01/01/70 00:00 | |
| Threshold voltage | 01/01/70 00:00 | |
| I would give this a try... | 01/01/70 00:00 | |
| ? | 01/01/70 00:00 | |
| Greinacher voltage doubler | 01/01/70 00:00 | |
| You have a good memory!!! | 01/01/70 00:00 | |
| Why use 9V | 01/01/70 00:00 | |
| Availability.. | 01/01/70 00:00 | |
| True but.. | 01/01/70 00:00 | |
Absolutely! | 01/01/70 00:00 | |
| Answers... | 01/01/70 00:00 |