Review of The TeensyBat 4.1 DIY Bat Detector

The TeensyBat 4.1 DIY Bat Detector

 The TeensBat 4.1 kit - Main parts illustrated

(stock photo from teensybat.com)

The TeensyBat is a Do-It-Yourself (in this case, assemble-it-yourself) bat detector. It features a few different modes of detection. As well as a myriad of features and customization's.

The TeensyBat 4.1 As it arrives (to me in The US)

from The Netherlands

The TeensyBat is based on a development board made by PJRC. You may see more information about the board, by checking out the PJRC Site.

Size of the completed unit is 116x68x36mm (4.7x2.7x1.5in)

The TeensyBat 4.1 kit - Unboxing

The TeensyBat 4.1 kit - Main components

Building The TeensyBat 4.1 kit - 

The one "fiddly bit" is encountered in the beginning. It's the installation (soldering of) the 2 PSRAM chips. This is discussed/shown on page 4 of the construction manual. Once those two small ("optional") chips are soldered onto the Teensy board itself; the rest is pretty easy.

It is right about this point, where I usually touch on the price of the bat detector under review.

But, this Do-It-Yourself bat detector kit is a bit different...

To begin with, you purchase/order the kit from the teensybat.com site.

At the time of ordering, you should decide which options you'd like your bat detector to have (Temperature sensor? External microphone jack? GPS unit?).

Then, you'll need to purchase the following items: 

• 2 PSRAM 8MB Chips @   €3 each         ~   €6 (TeensyBat)

• Teensy 4.1 Board………………………………….~ $41.99 on Amazon.

• 3.7v 6500mAh LiPo………………………………~ $17.99 on Amazon.

• Pack of CR2032 Batteries…………………… ~   $5.99 on Amazon.

Total cost - As configured - Roughly $200 US Dollars (I opted for the temperature sensor, and 3.5mm jack (for use with ext. microphones). This is the jack located at the front of the unit; next to the (main) microphone.

Now this presumes the builder is familiar with soldering, and already owns the tools & materials needed for completion…If you don't:

Additional basic tools & materials needed to build kit: 

• Soldering iron 30w to 60w - Simple “pencil-type” is sufficient.

• Standard, Rosin-Core solder - “60/40” is fine.

• A fine, flush cutter - similar to a wire cutter.

• Screwdrivers.

• Files, Dremel-type tool is a “nice-to-have” but not necessary.

• Desoldering pump, or Desoldering wick.

• Tweezers would be useful, as well as a tip cleaner for iron.

Building The TeensyBat:

• The construction Manual is found under the ‘Build One’ tab on the site.

• One of the first steps, is to install/solder the 2 PSRAM chips onto the Teensy 4.1 board.

• The remaining soldering & assembly isn’t very difficult at all.

• The only other “fiddly bit” is the microphone.

• There may be some minor modifications needed to the enclosure openings.

The TeensyBat just so happens to have a lot of features. You can spend a bit of time just customizing it.

From left to right:

Temperature sensor, 3.5mm jack for external Mic, Main microphone

Features of The TeensyBat:

• 2.8inch color display that shows a live spectrogram and low,peak and high frequencies.

• Heterodyne, Auto-Heterodyne and Frequency division listening modes (using headphones).

• Recording up to 384kHz sample rate to micro SD card (maximum supported size 32GB, Class10 or better required).

• Playback on slow speed (1/5 to 1/20 ratio) or full speed (full speed only works up to 281kHz sample rate).

• Rechargeable lithium battery can easily last a whole summer night (standard USB (C) charger is needed).

• Internal LiPo battery charged by standard phone charger.

Using The TeensyBat resources:

• The ‘Using the TennsyBat’ Tab - Found on the TeensyBat.com site.

• There are 4 YouTube videos there: Basic Use, Settings, Playback & Record.

• At the bottom of the same page is The TeensyBat User Manual V1.4

 

• Rechargeable Li Po battery (standard USB (C) charger is needed).

The TeensyBat does take a bit of time to get used to. As with any bat detector, it comes down to navigating the buttons, knobs, and features (enabling/disabling). It becomes somewhat more difficult (frustrating?) when you're out in the field; and bats are flying about - You don't want to miss any!

Simply familiarize yourself with the 4 main controls - 2 red buttons, and 2 red-topped knobs. The knobs feature built-in detents - Here's a look:

2 Buttons, each on either side.

2 knobs bottom/middle.

(stock photo, courtesy of Edwin Houwertjes) 

Once you become familiar with the 4 main controls, it becomes very easy to use.

What I call my version of a short quick start guide:

• Power on The detector, select Mode (Het, Auto-Het, F_D, TE*). 
• Adjust volume to 50 or below. 
• Adjust gain to 15 or below. 

*Time Expansion is not likely to be available on The TeensyBats going forward.

I typically set my volume to ~ 40, and set my gain to somewhere around 12.

As you might expect, increasing the gain allows you to pick up bats from slightly greater distances. 

Keep in mind that these settings are relative - Since the TeensyBat doesn't come with a speaker as standard / or built in. Without an external speaker attached, the volume doesn't really have much effect on anything. With the rotary gain control, the difference as you raise or lower it, will affect the overall sensitivity of the unit. 

This TeensyBat bat detector is very sensitive, and has the ability to pick up bats at respectable distances. 

It also picks up bat calls loud and clear, from off axis. 

This was apparent, when comparing the TeensyBat side-by-side to the Echo Meter Touch 2 Pro, and The SSF3 bat detectors.

You get to put whichever bat sticker(s) you want on it!

If you'd like to listen to the bats you're picking up: You'll have to provide an external speaker, and a male-to-male 3.5mm audio cable (for connection to the detector's audio out jack).

There are also small, rechargeable, Bluetooth speakers available from several online stores. I used my trusty, adjustable, RadioShack external speaker (it runs on a single 9 volt battery).

This TeensyBat  picks up bat calls loud and clear off axis (bat calls coming in at angles to where the microphone is actually pointed).

Aside from this obvious advantage, I would compare it's general ability to be roughly similar to that of The Echo Meter Touch 2 Pro.

When you hear a good clean bat call, you can press the record button, and record the calls onto SD card.

When recording bat calls: It records ultrasonic sound to the Micro SD card in full spectrum, regardless of the listening mode used.

The calls are easy to listen to, using just about any standard audio player App you may have.

For beginners: Keep in mind, you'll be able to hear the (FS) recorded calls, using things as basic as Windows Media Player (in Windows) and QuickTime (in Mac).

The recorded calls may be analyzed in many different sound analysis programs. Playing the first batch of (FS) calls back, with these professional Apps produced mixed results.

What happened in my (first) examples, was: Kaleidoscope (from Wildlife Acoustics) did not play calls back in a pleasing manner. In my particular case: 

I had more electronic devices near the TeensyBat than I should have - causing interference, etc.

After more recent experimenting, this does appear to be what happened. When no other electronics are in it's vicinity, it produces recordings of bat calls which are more than adequate.

The other selections available are heterodyne, auto-heterodyne, and time expansion. We will need to omit time expansion for now, and just focus on the other modes.

The early renditions of The TeensyBat also allowed listening in time expansion mode, I have done it, but not very often. Going forward, TE will not be an option. 

This bat detector kit would be ideal for someone with electronic kit building experience; and an interest in bats!

The full spectrum recordings of bats were audibly pleasing, and of course, were also recognized by Kaleidoscope (Wildlife Acoustics). Bat calls heard while listening in heterodyne mode, were very pleasing as well.

Pros: 

• Very customizable in re: to options desired, at time of construction.

• Audio “ring” pre-buffer (records several seconds ahead).

• Sensitive microphone - Both detecting & recording.

• Records up to 384kHz sample rate, onto Micro SD card.

• Has several advanced features which may be adjusted: Filters, Gain, etc.

• Aesthetically customizable (display colours/themes).

• Constantly being improved upon via firmware, etc.

• Has proven itself able to withstand very cold temperature without incident.

Cons:

• Requires soldering skills to build.

• Does not feature a speaker - Must use external speaker, or headphones (for live listening)

• Battery life not comparable to some Pro-level detectors.

• Recording bat calls is not as easy/automated as pro level detectors.

I plan to create/post some videos, of the TeensyBat in use — on my YouTube channel.

I hope to include some videos on: Simple setup, on attaching an external speaker,

and on how to use the detector in general. Even more importantly, I'd like to

confirm that the noisy recordings I got, were due to electronic interference.

Review of the recently released book, 'A Miscellany of Bats' will be the next item up...

Until then,

Happy bat detecting!