TeensyBat diy batdetector


Welcome to my Teensybat page. I am Edwin Houwertjes an enthusiastic electronics hobbyist working with the TeensyBat, Teensy based d.i.y. bat detector for a few years now. (Teensy is a development board made by PJRC) It takes up a lot of my free time but this device is too much fun to keep just for myself.

I hope the help you build a detector like this TeensyBat using the information on this website.

Now Teensy 4.1 based!  (september 2021)

The first new teensy 4.1 based main boards are here. This PCB is not designed to be built completely by the home builder because there are too many tiny surface mount parts on it. I will have a bunch of these circuitboards assembled with all surface mount parts on it so you only need to solder the larger parts. The whole audioboard, microphone amplifier as wel as the whole battery charge and protection circuit is on the printed circuitboard.

This will mean there is a lot less to solder but the PCB will be more expensive but the whole project should be near the same price since you do not need an audioboard and other components as these are already mounted.


I did release the design and production files for the Teensy 3.6 based version, I'll keep these Teensy 4.1 based files for my self. 


Why Teensy 4.1? Well a huge advantage is the extra memory we can mount. It will give you a nice prerecord buffer that allows you to store about 4 seconds of sound that you just heard.


Bat detector that shows received sound. od a common pipistrelle.

Keywords: bat, detector, batdetector, vleermuis, vleermuisdetector, teensy, time expansion, heterodyne, frequency division, frequentiedeler, ultrasoon, spu0410lr5h, spu0410lr5h-qb, zelfbouw, diy, homebrew, spectrogram, waterval, waterfall, classify,

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Frank F
2 months ago

The seller was very kind and helpful regarding questions, extra parts, billing and shipping. I'm using the device every week since I bought it in December last year. Can definitely keep up with professional devices and never failed me before. I had some difficulties getting it to work because I am really bad at soldering but got it to work after a few hours.

Rob S
11 months ago

Edwin, I sit here with a freshly completed TeensyBat on my desk. It works fantastically and I'm very impressed by it. Bravo!

I am a bat worker in the UK and frequently use ~£900 bat detector units. This TeensyBat build is way cooler and has so many more features. I look forward to using it out in the field.

Thank you for creating this awesome project and making it publicly avaliable.

Edwin Houwertjes
a year ago

Normally I do not write here but answering Thomas gives some idea about the developments.

Teensy 4.1 version boards are ordered, but production takes some time.
The Audioboard is still used. It provides extra gain setting and is also usefull for playback (connecting headphones) we will be using the audio board but it is integrated on the main board.
We do uses extra memory that can be soldered directly to the Teensy it is not used to help reducing "writing sounds" I helps us store sounds that already passed a few seconds ago.

The noises of the SD card writing can be reduced by separating Vin(Teensy) and input of te 3.3V LDO(IC2), and give each their own RC filter (ad an extra R10/C10 circuit)

a year ago

I am quite happy with my teensyBat based on v0.2a. Would it be possible to come up with a new hardware version based on teensy 4.1 and without the need for the extra audio board (built-in ADCs only)? This would reduce the cost.
Would it also be possible to "record" the signal into a buffer for some time and save it later to the SD card? This would avoid noise coupling into the signal from SD card write operations.

Thank you so much for your effort to make this project available for a bat enthusiast like me.

Ap Bruinenberg
a year ago

Prachtig project dat zeer goede resultaten oplevert, dank voor de creators !

a year ago

In 2019 heb ik een compleet werkende detector van U gekocht. Ik ben daar zeer tevreden over. Ik kijk met belangstelling uit naar de 4.1 update. Ik zou graag een kit, pcb of onderdelen willen bestellen als het beschikbaar is.

Tom Kreyche
a year ago

Dear TeensyBat team - great work! I look forward to your new hardware release and will purchase a kit or circuit board or parts when it's available.

Tom Kreyche KF7NOP, Seattle Washington USA

pieter smit
a year ago

Just loaded the new 1.3 software, went flawless into the Teensy. Its fantastic that image now continues while recording. And the auto gain (plus downward expanded gain reach) will hopefully solve the problem that bats flying close by, overpowered the input channel. Thanks for all the good work!

Jan Thyregod
a year ago

Facinating project and I would like to build one for a friend. Please contact me as I cant mail you once the new PCBs are available. Br Jan

Bartle de Leeuw
a year ago

ik zounhier graag wat meer over willen weten