Timeline for Bats ultrasounds detector with LM324
Current License: CC BY-SA 4.0
14 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 16, 2023 at 19:03 | answer | added | Gos | timeline score: 1 | |
| Jul 30, 2023 at 17:35 | comment | added | Audioguru | A lousy old LM324 is not used for audio because it does not produce high audio frequencies so you need a better opamp since most audio opamps operate fine up to at least 100kHz. The 40kHz piezo transducer produces ONLY 40kHz. The breadboard causes high frequency oscillation instead of amplification. | |
| Jul 30, 2023 at 14:55 | answer | added | glen_geek | timeline score: 1 | |
| Jul 30, 2023 at 13:52 | comment | added | glen_geek | That piezo microphone is suspect. If it is a common ultrasonic 40kHz transducer, it is sharply resonant near 40 kHz making it less-sensitive at other ultrasonic frequencies. You might be able to extend its bandwidth with an RL network. It may be better to drive a proper multiplying mixer from the microphone, then amplify the mixer's audio output. Some active multiplying mixers have gain. I'd suggest a SA612 mixer from NXP | |
| Jul 30, 2023 at 13:26 | vote | accept | Gos | ||
| Jul 30, 2023 at 12:50 | comment | added | Gos | Ok, I was not aware. Acually I will get some LM386 soon and I will replace it. Then I don't need the LDO neither. | |
| Jul 30, 2023 at 11:58 | answer | added | Andy aka | timeline score: 3 | |
| Jul 30, 2023 at 11:34 | comment | added | glen_geek | Perhaps unwise to use the class-D PAM8302 audio amplifier - it is also an ultrasonic generator. Better to use old-school linear amplifier here like LM386 or equivalent. | |
| Jul 30, 2023 at 11:07 | history | edited | Gos | CC BY-SA 4.0 |
added 52 characters in body
|
| Jul 30, 2023 at 11:06 | history | edited | Gos | CC BY-SA 4.0 |
added 12 characters in body
|
| Jul 30, 2023 at 11:04 | history | edited | Gos | CC BY-SA 4.0 |
edited body
|
| Jul 30, 2023 at 11:02 | history | edited | Gos | CC BY-SA 4.0 |
added 4 characters in body
|
| S Jul 30, 2023 at 10:55 | review | First questions | |||
| Jul 30, 2023 at 11:22 | |||||
| S Jul 30, 2023 at 10:55 | history | asked | Gos | CC BY-SA 4.0 |