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  • pe1pwf's Avatar
    Yesterday, 06:36 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    Thank you for the nice pictures Cor. I hope I can show the effects of VAG setting with a few Audacity screenshots. It will show it is hard to know when the system gets saturated because the signals differ quite a...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-26-2019, 08:18 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    Compiling again in windows. I just put all the files I used together in this zip file. The text below is also in the zip file..
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-25-2019, 08:46 AM
    pe1pwf replied to a thread Bat detector in Audio Projects
    Yes I removed C2, it was supposed to "short" RF signals to ground. Working with the opamp amplifier it just seemed to pick up display update noise so I chose not to place it. Also C1 can be changed, If you want to...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-19-2019, 04:33 AM
    pe1pwf replied to a thread Bat detector in Audio Projects
    The resistors are all soldered on the teensy so these are between the teensy and audioboard. I hope this helps. On the last boards I soldered I cut the pins like this so that mounting was easier.
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-18-2019, 08:08 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    Yes I did, somehow it seems I did not post my reply yesterday. I set the amplification close to 40dB on the TL972, these are the results i got in a quit room with SGTL gain set to 0 I also did the same with...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-17-2019, 08:34 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    I just updated some documentation. I don't quite remember if I shared the link to these files before but any eBay buyer of the V0.2 board als got the link form the item description. The link now holds the new files....
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-15-2019, 07:46 AM
    pe1pwf replied to a thread Bat detector in Audio Projects
    The externder was just an idea to be able to cut a power supply track and put a separate 3v3 source on the SD card to try and get the writing noise out of the teensy. I did some experiments again with the SGTL...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-15-2019, 05:08 AM
    pe1pwf replied to a thread Bat detector in Audio Projects
    Frank, Maybe you could use a SD-card extender like this to be able to seperate the SD powersupply from the Teensy. On the teensy it is very hard to do that but here you can easily cut a track. There are also...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-14-2019, 09:14 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    In single ended output the -out pad is floating. I do have to mention the codec gain used is quite high, This is what I see with codec gain on 10 I also made a few noises....
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-14-2019, 02:17 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    Thanks for the 0.94 version Cor. I ill upload it to my detectors soon. I have been messing with the ICS-40730, I did not like the signal that remained on just about 22-23Khz. I tried a differential amplifier...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-09-2019, 04:42 AM
    pe1pwf replied to a thread Bat detector in Audio Projects
    I am still using the SPU0410LR5H-QB, the ICS-40730 should have a little less noise but it was hard to tell the difference. The SPH0641LU4H-1 is the PDM version of the SPU0410LR5H-QB. I never tried anything with that...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-08-2019, 08:48 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    This is starting to become obsessive.... Dangerous stuff this kind of hobby. I have been out to capture some bat calls and try different cones on my microphone. As far as I can tell there is much less 23KHz...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-07-2019, 09:58 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    I just seem to have lost a lot of noise here..... I am using the V0.2 board with opamp amplifier and a SPU microphone on this one. I noticed the display update noise could be heared stronger than on the transistor...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-06-2019, 04:42 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    Hi Seriesman, the impedance matching of a transistor amplifier is quite complicated. It looks like this link has some nice information on impedance calculation. Maybe the transistor amplifier can be matched even...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-05-2019, 07:19 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    No problem Cor, I was just thinking out loud. These were the only two functions I would probably use on playback. I just uploaded the new hex file to my detectors. Will go out later when the bats come out. ...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-04-2019, 03:37 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    Not yet finished on the roof here.... The supports of the solarpanels were sinking into the bitumen. I thought I had a big enough surface but with the very high temperatures the bitumen seems to get quite weak. Now...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-04-2019, 09:26 AM
    pe1pwf replied to a thread Bat detector in Audio Projects
    Take your time, it looks like it is gonna be a nice day for a ride, well at least here it is. Unfortunately I do have to repair a leaky roof so we have some work to do here. The delay looks about as long as it...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-04-2019, 08:14 AM
    pe1pwf replied to a thread Bat detector in Audio Projects
    Playback works fine, somehow recording start seems to be delayed by 4 seconds or so. Edwin
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-03-2019, 10:27 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    As it turns out, the single transistor amplifier also is working quite well. If you already buit the transistor amp I guess you don't really need to build the opamp version. There might be a tiny bil less noise in...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    08-03-2019, 07:58 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    I promised some of you to send a message when I was willing to sell the extra experimental boards I have. Since this new board was ment to work better than the transistor amplifier board, I was not quite ready to sell...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    07-31-2019, 08:10 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    Hi Rémis, I think I remember you said adding a capacitor between the 3v3 pins on the audioboard and some pins on the TFT screen helped reducing noise. In the past I tied to reduce noise but most seemed to be data...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    07-30-2019, 09:31 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    So here we are again, using the opamp amplifier, and ICS microphone in single output mode. I did change the biasing resistor to match the impedance of the microphone, this helped to get rid of the unwanted signal on...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    07-29-2019, 09:12 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    Hi Remis, I do have an oscilloscope. A cheap one but I should be able to see some signals I guess. Although these seem quite tiny and my oscilloscope might not be the best choice. I have no electronics education...
    476 replies | 34494 view(s)
  • pe1pwf's Avatar
    07-29-2019, 08:04 PM
    pe1pwf replied to a thread Bat detector in Audio Projects
    Struggling here with the opamp version board, somehow I seem to have the spurious signal that was described and all of it's harmonics now that I am amplifying with a tl972. ( The one on the right.) It does not realy...
    476 replies | 34494 view(s)
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About pe1pwf

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About pe1pwf
Location:
Netherlands
Interests:
Ham radio / electronics
Occupation:
Mechanical and electrical service tecnician

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