Bat detector

Housing

Hi,

I think it would be interesting to see how people have currently been building/housing for the detectors. Edwin (PE1WF) has been so kind to share his way to build a detector and it might be nice to see some more ideas/options ... if any are out there. That way we can also learn the way the hardware part of this project can be done. I have shared my not so good looking setup many replies ago ;)

regards
Cor
 
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Photo of my build

CorBee said:
Hi,

I think it would be interesting to see how people have currently been building/housing for the detectors. Edwin (PE1WF) has been so kind to share his way to build a detector and it might be nice to see some more ideas/options ... if any are out there. That way we can also learn the way the hardware part of this project can be done. I have shared my not so good looking setup many replies ago ;)

regards
Cor
Click to expand...

Hi
AS requested a photo of my build. I use an external PSU, easy to change if it runs out, less electrical noise in the case. Case was one I had spare from a previous project. DSCN1499R.jpg
 
remis said:
I plan to offer one box to a friend*: Thus I need a short manual. Please use doc 2003 win version or same in Libre office under Linux:easier to modify for every body if you want to add your information, correction

It is not easy to summarize all the functionality : big work around software. I have many questions: some answer are in this thread..where…

TE_mode ( need more explanations)
Denoise, Spectrum, Play vs Play R
I try to record and play file in PASS mode. Could you explain why voice is no more understandable when I read it. Where is TE introduced?

May bee there are too much to answer for a first time...
Click to expand...

HI. Many thanks for posting the short manual. I have been thinking that a manual is a good idea, TeensyBat is getting a bit complicated to carry it all in your head, especially when, like me, your the wrong side of 70. I am retired but used to be an IT teacher trainer and wrote many manuals to simplify complicated software so that teachers could use it in a classroom situation. I am only to happy to help in any way with the manual, spell checking, proof reading etc.
 
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 and clock signals to the TFT signals that were not so easy to reduce.
Can you tell me on wicht pins of the TFT screen you added what kind of capacitors?

Kind regards,

Edwin
 
decoupling

To add detail message #316:
I improve decoupling with 470nF 0805 ( or 0603 ) : They are soldered directly beetwen supply pin and groud. It could be the next pin, (if pin is gnd) or i use the ground plane. For TFT I add capacitor on your PCB and directly on screen side. See pictures, with two differents capacitors. You can do that for all VCC, 3V3 signal. Without microphone and wire input connected you should have a flat spectrum. If yes you have validated the correct decouling : there is no more perturbation in conducted mode.
 

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Manual

Hi,

I have uploaded a word version (made with LibreOffice) of the manual with a new structure/image and more information at
https://github.com/CorBer/teensy_batdetector/tree/master/documentation

Its by no means a manual yet but I hope this helps to start building a real manual. One of the things I would like to consider adding is to show a few step-by-step examples of "real" session of using the batdetector with several screenshots on a single page. For instance "How to start recording" would than show that you first need to move the left-encoder to the BUTTONL option, then press the encoder, choose RECORD and press the encoder again. etcetc.

I was planning to upload this on the forum but the file is allready to big for that purpose so I am using the Github for this as that is easy. When any of you adds/changes (please do this in a coordinated way) things I will upload that to Github when asked.

regards
Cor
 
IMPORTANT: Issues with play of recorded files

Hi,

I was allready notified by Edwin that the latest versions have problems with playing recorded files. When I checked yesterda my detector also seems to be affected by this, I am using v0.89.
When I go the to play menu I do only see the 1st filename andcannot choose any other and it also does not seem to play the file. In fact it looks to lock the system so I need a full restart. Currently its unclear to me when this bug has crept in and what has caused it. I will try to step back a few versions and would be happy if any of you can report back on this too.

regards
Cor

EDIT: I just checked if the recording was suffering the same issues. There seems to be no problem in recording !!
EDIT2: Unclear what causes the issues, no fast solution !
 
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Just checked and the version that is available on the 7th of june (v084) does still have a working system to replay files. So it looks as if the changes we have made afterwards when trying to solve the issues with the SDcard (compilation issues on windows setup) have caused this. I will search further
 
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 before but now after some adjustments in parts values I am pleased enough with the results.

I tried to let you guys view the google drive where the schematics and building information are.
I have to admit the building instructions need some extra work but should already give some good directions.

Link to google drive folder.
 
Nice work Edwin and thanks for sharing not only the option to get boards from you but also your design/setup. I am hoping to start building mine using your PCB and guidance after the weekend.

regards
Cor
 
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 the recordings, but the display noise seems to be a bit stronger. It also seems to be a bit quicker at picking up the bats, but to be sure about that I should build several detectors of both types.
Getting rid of the 23khz siignals and its harmonics was done by changing the biasing resistor to match just about the impedance of the microphone. In stead of the 2.2uF capacitor I later tried a 100uF low esr cap. That seemed to help improve a tiny little bit.

I also have been playing with a differential amplifier circuit. Unfortunately what I hoped did not really happen.
I hoped the display update noise would be canceled out but somehow it did not make a huge difference between the single ended setup and the differential amplifier.

So conclusions sofar:
All amps work almost eqally well.

Transistor amplifier, is a good working solution.
Single ended opamp, seems bit more sensitive on picking up bats but bit more noise from display updates.
Differential amplifier makes thins more complex but I was not able to cancel out the display noise.


Edwin
 
CorBee said:
Just checked and the version that is available on the 7th of june (v084) does still have a working system to replay files. So it looks as if the changes we have made afterwards when trying to solve the issues with the SDcard (compilation issues on windows setup) have caused this. I will search further
Click to expand...

Hi,
I am making some progress on this, I have been able to isolate the issue as a conflict between the playing/recording parts of the code. There is no simple solution yet but it also does not look like something that cannot be solved at all. Just dont use the playing-functionality currently is my advice.

regards
Cor

EDIT: just minutes after this I seem to have found a solution, hopefully to be shared soon
 
v0.91 code adapted to allow replay again (needs to be tested !!!)

Hi,

I have uploaded v0.91 with the new code that should (hopefully) solve the issues with replay of file (max_files on SD currently 50 but that will change), the hex is also available.

Please test this and report back.

regards
Cor
 
pe1pwf said:
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 the recordings, but the display noise seems to be a bit stronger. It also seems to be a bit quicker at picking up the bats, but to be sure about that I should build several detectors of both types.
Getting rid of the 23khz siignals and its harmonics was done by changing the biasing resistor to match just about the impedance of the microphone. In stead of the 2.2uF capacitor I later tried a 100uF low esr cap. That seemed to help improve a tiny little bit.

I also have been playing with a differential amplifier circuit. Unfortunately what I hoped did not really happen.
I hoped the display update noise would be canceled out but somehow it did not make a huge difference between the single ended setup and the differential amplifier.

So conclusions sofar:
All amps work almost eqally well.

Transistor amplifier, is a good working solution.
Single ended opamp, seems bit more sensitive on picking up bats but bit more noise from display updates.
Differential amplifier makes thins more complex but I was not able to cancel out the display noise.


Edwin
Click to expand...

I will probable stick to the transistor based amplifier on your earlier PCB or use your new PCB and create a small subboard with the preamp directly behind the microphone.

Cor
 
pe1pwf said:
Playback works fine, somehow recording start seems to be delayed by 4 seconds or so.

Edwin
Click to expand...

Hi,

I think I know where that originates, I will change that later today ... first I am going to do a bikeride.

Thanks for testing
Cor
 
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 takes to display the files list on playback.

I did also discover a weird problem with one of the ould micro SD cards i have been using, on a 2GB Samsung SD card the recording gets messed up. Yesterday I was trying to compare files.
Both recorders used 0.88 version software. I recorded exactly the same but recordings looked like they were a lot shorter. I tested by playing a counting voice that I sped up from 44 to 281khz. When I played back the recoderd file, there are parts missing but even things appeared to be in the wrong order...
Weird!

Well, better not use that card again.....

Edwin
 
pe1pwf said:
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 takes to display the files list on playback.

I did also discover a weird problem with one of the ould micro SD cards i have been using, on a 2GB Samsung SD card the recording gets messed up. Yesterday I was trying to compare files.
Both recorders used 0.88 version software. I recorded exactly the same but recordings looked like they were a lot shorter. I tested by playing a counting voice that I sped up from 44 to 281khz. When I played back the recoderd file, there are parts missing but even things appeared to be in the wrong order...
Weird!

Well, better not use that card again.....

Edwin
Click to expand...

Ride of 80k went fine, enough wind like always ;)

The delay is associated with the switch between the playing or recording mode. It now switches every time you start a recording whilst that can be done also once at the moment you switch to the recording mode.
I will wait until later today with the implementation, maybe other reports will still come in.

Cor
 
CorBee said:
Ride of 80k went fine, enough wind like always ;)

The delay is associated with the switch between the playing or recording mode. It now switches every time you start a recording whilst that can be done also once at the moment you switch to the recording mode.
I will wait until later today with the implementation, maybe other reports will still come in.

Cor
Click to expand...

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 I ran out of materials to repair the last pieces but my body dos not mind.... finally some rest.


The first time at playback I could not change the samplerate, I have no idea why, al times after that worked fine.

Once play is selected the unit switchhes to a low samplearte producing weird noises near my computer. Is it possible to turn of the detecting mode as soon as play is selected.
It now staus in the last detecting mode but at a low samplerate.

At the time we are actually playing, it would be nice if the left encoder has volume function. (it seems it is selecting files now)

Edwin
 
The temperatures of previous weeks were off course beyond specs nearly.

I need some time to get the recording/playing system working as before. For instance in the original mode the system would read the allready recorded filenames on the SDcard rather fast and now we literally have to wait several seconds. So this needs a good check, and I also have noticed (like you do) that during play you can actually hear sound coming in through the mic. That should not at all be possible since I unlink the mic from the system the moment we are switching to play. All in all, there is progress but this is not as it should be. In the mean time I will also think of a handier way to handle the play system (including volume).

Hope you find a bit of rest !

Cor
 
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V0.92 further improvement in the PLAY/RECORD setup

Hi,

I just uploaded some work I have done on the PLAY and RECORD section. On my detector this seems to work again as planned and it also has several improvements compared to previous versions.

This is the info I have also put on Github to summarize the changes:

v0.92 -further work on the setup to record/play files NEEDS TESTING
-filename display shortened so no overlap with other menu
-filename selection (when playing) is now cyclic.
To go to the latest recording just turn counterclockwise instead of stepping through all previous
-rightside menu allows setting of samplerate (in all modes)
-during playing of files microphones will be switched off
-maximum number of files to be stored 999 (BXXX_RRR.RAW) XXX=0..999 RRR=samplerate in Khz
Click to expand...

@pe1wf Edwin: You wanted to have direct access to volume when playing a file using the left-encoder. This is not impossible but could complicate things. I will try to explain this in a simple description of the steps a user needs to take to go from the detector to playing and back to detecting.
Currently:
When the user is in the detector mode (actively detecting) :
1) user changes the leftencoderMenu to Play,
2) presses the encoder, filenames are now visible
3) user selects the file to be used for replay
4) user presses the PLAY button (microPushLeft)
5) user either presses STOP (to stop playing) with the microPushLeft first or directly presses the LeftEncoder (stops all play and switches back to detection)

with additional functionality added to the left encoder:
1) user changes the leftencoderMenu to Play,
2) presses the encoder, filenames are now visible
3) user selects the file to be used for replay
4) user presses the PLAY button (microPushLeft), the leftencoder now directly switches to Volumemode and allows the volume to be controlled
5) user either presses STOP (to stop playing) with the microPushLeft, the leftencoder again displays the filename and allows the user to choose a file
6) user presses the leftEncoder once more to get back to detection

So it is possible but I think its easier - to simply change the function of the rightencoder during replay. Maybe you did not know but the rightencoder can be set to any of its normal functions during replay. By default this switches to SampleRate when you start replay but you can press that and set it to volume to allow volumecontrol.

I hope that again some people can test the whole setup as I have made quite a bit of changes in the setup/sourcecode. If things are stable we can again move forward

regards
Cor
 
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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.

Edwin
 
pe1pwf said:
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.

Edwin
Click to expand...

Well I think the way the menu is currently constructed is not yet the most logical setup. So we can do something about this when overhauling the menu structure once more.
One of the things that isnt logical is that for PLAY we can just choose from the main menu but for RECORD we first have to set the ButtonL function. The other way around would nearly be more logical as you want to switch to recording ASAP whilst going to play cannot be really urgent.

Hope you had a good night with the detector.

Cor
 
How to reduce the 23KHz noise peak

pe1pwf said:
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 the recordings, but the display noise seems to be a bit stronger. It also seems to be a bit quicker at picking up the bats, but to be sure about that I should build several detectors of both types.
Getting rid of the 23khz siignals and its harmonics was done by changing the biasing resistor to match just about the impedance of the microphone. In stead of the 2.2uF capacitor I later tried a 100uF low esr cap. That seemed to help improve a tiny little bit.

I also have been playing with a differential amplifier circuit. Unfortunately what I hoped did not really happen.
I hoped the display update noise would be canceled out but somehow it did not make a huge difference between the single ended setup and the differential amplifier.

So conclusions sofar:
All amps work almost eqally well.

Transistor amplifier, is a good working solution.
Single ended opamp, seems bit more sensitive on picking up bats but bit more noise from display updates.
Differential amplifier makes thins more complex but I was not able to cancel out the display noise.


Edwin
Click to expand...

Hi
I have built and am using the 1 transistor amplifier version and running 0.92 with no problems so far. I note that you can get rid of the annoying 23Khz noise peak by altering a resistor to match the microphone impedance more accurately. As far as I know I got the SPU microphone from you with the PCB. Which resistor do i change and what value doi I replace it with please. Help appreciated
 
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