Technical Data Horchbox 1.5

The Horchbox 1.5 is available since beginning of 2011. It is an improved version of the standard Horchbox with better sound quality, improved microphone amplifier and other small changes.

The Standard Horchbox 1_5


  • Samplerate up to 600 kHz/16 Bit
  • SD Card support for SDHC/SDXC
  • Temperature and light sensor included
  • Battery supply voltage from 6 to 16 Volt
  • Using standard 2400 mAh batterypacks it runs up to 10 days
  • PC Software system with extensive functionality included
  • Powerfull, but simple configuration using the PC Software
  • Price 750 Euro including 19% VAT


Microphone and Recording

The microphone supports a rather wide ultrasonic frequency band, starting from about 20 kHz up to 75 kHz. It even extends to more than 100 kHz, but with less sensitivity.

The analog data is preprocessed for the AD converter using a specially for this application designed amplifier circuit. The AD converter samples the data using 16 Bit and up to 600 kHz samples/seconds (the user can select from either 200 kHz, 300 kHz or 600 kHz). The digital data is stored on a SD Card - SDHC and SDXC are fully supported, the system has been tested with up to 32 GByte SD cards.

Even if no bat is detected the system records basic sensor data like temperature and light, also including battery voltage.

Recording trigger

The Horchbox checks the incoming acoustic data and starts recording if appropriate. The user can choose on of the following three trigger mechanisms:

  • Threshold: When no other sound is expected this trigger is usefull. It starts recording whenever a noise is detected.
  • Bat-Detect: This algorithm scans the audio input for bat like patterns, and starts recording if the input is close to a bat-call.
  • Combined: This is a mixture of both algorithms: Since the Bat-Detect algorithm needs some calls to start recording, the first calls might be lost. Using combined the box starts recording like selected in Threshold, but automatically deletes the record, if no bat was detected using Bat-Detect while recording. This algorithm uses more power and the livetime of the SD Card is reduced, since data is written much more often compared to Bat-Detect.

Each trigger uses a sensivity value, which the user can select. There are also some extended features like a rain exclusion filter or values to configure the expected noise level (like the noise close to a road).

Additionally the box include an time controlled sleeping mode, the user can select at what time the box sleeps. This reduces power consumption and also the number of records.

In parallel a light dependend sleep mode activation is possible.

Power supply

The box is designed to be powered by standard 7,2 Volt RC accus available in plenty online shops. The recommended accu size is 2400 mAh, the box will run up to 10 days using one of these accus. For longer runtime a maximum of two accus with 5000 mAh each can be put in the enclosure, which will result in a runtime of more than a month. Depending on the usage other batteries can be used, like lead acid car accus with 12 Volt.

Price and further options

The Horchbox 1.5 costs 750 Euro, already including 19% VAT in Germany. The box itself, one USB cable for communication and one 2 GByte SD Card is included.

Optionally a battery pack (2400 mAh/7,2 Volt) and charger can be ordered for 50 Euro.