Back by popular demand, our second year of offering the chance for everyone to build their own LOW cost, and HIGHLY capable bat detectors and ultrasound recorders. Do you fancy auto tuning Heterodyne AND Time expansion!
How to build your own
We are running workshops where you can build your own device from the Pipistrelle family of devices. It is free to come along to a workshop, to learn about the Pipistrelle detectors, and watch them being built.
However if you want to build a detector, no experience (of soldering or anything else) is needed. The materials cost between £8 and £22, depending on which model you would like, and in addition there may be a small venue hire fee.
To build a detector you will need to bring along:
- A steady pair of hands! Some of the components are only mm long. The leader will demonstrate methods to help with accurate placement.
- Good close to eyesight. If you use reading glasses, perhaps bring along an extra pair a bit stronger than usual.
- To test your Pipistrelle detector. Batteries and wired headphones, or speaker, with a standard 3.5mm jack.
A headtorch and magnifying glass may also be useful if you have them, but the leader will have some to borrow.
What does the Bat Group supply?
All the components, materials, tools and equipment needed to build the detectors or recorders.
A leader from the bat group will start with a briefing about the devices, and then walk you through, step by step, the instructions to safely build and test them.
How do I book?
All the future workshop details are on the events page of our website, and listed below.
To book, follow the link in the workshop you are interested in attending below, there you will be able to, either:
- For SWT events – Register and pay your materials/venue costs online , or
- For SBG events you can register via email. Then pay your materials & venue fee via BaCs donations. SBG Bank details are here, or in cash on the day.
What will you be building?
The Pipistrelle family of devices has been developed by Phil Atkins from Wiltshire using the RaspberryPi Pico. They offer advanced abilities at a truly market disrupting cost, with features previously only available on devices costing hundreds of pounds. They also have upgradable software on board, which means new features may be made available at a later date.
To achieve the low cost, they use a very simple construction, and hence the long term durability of these new devices is currently unknown, and may depend largely on use. Examples of the simple construction include:
- They do not have an in-built speaker. Instead they use a simple 3.5mm jack for connection to wired headphones or speaker.
- An open battery pack is glued to the back of the device.
- A small off/on switch
- The microphone may not be quite as sensitive as the expensive commercial devices.
There are several options in the Pipistrelle family of devices, and we build them “Bat Detector”, or “Advanced – Ultrasound Recorder” Workshops.
We are now using some cheaper clone components imported direct from China, to achieve the lowest cost. These seem to work absolutely fine.
Bat Detector building Workshops
In these 3 hour workshops we build very capable bat detectors. If this is the first time you have done something like this, we would recommend you build either of these.
For mobile phone/tablet users: Griff 384kHz USB mic.
This microphone is worn as a credit card sized badge, and connected via a cable, to allow you see, hear and record bats via your mobile device. There are two versions:
- Mini Griff – Small square mic, no back cover, hence cheap! Materials cost = £8
- Griff 384kHz USB microphone – Bat shaped, with back cover to reduce noise. Materials cost = £12
You will also need a “On The Go” adaptor cable (can be supplied for an extra £2-4), but no batteries.
- For Android (or newer iPhone): a USBc to Micro USB OTG cable (£2)
- For older iphone/pad: A USBc to Micro USB OTG cable (£2, as above), and a USBc to lightning OTG adaptor (+£2), OR a lightning OTG camera adaptor (£2) and your own standard USBa to MicroUSB cable (you probably have dozens of these already, please bring one along)
You can also download the relevant app for your device to allow you to see, hear and record ultrasound:
- iOS app. Produces auto tuned Heterodyne and Time Expanded sounds. Search “Bat Detector” in Apple app. store.
- Android app. (in development). Currently has two manually tuned Heterodyne frequencies. Search “Batgizmo” in Google Play store
mini PiPistrelle Materials cost = £16
A auto-tuning Heterodyne and Time Expansion detector, The auto-tuned frequency is announced via a synthetic voice, and LEDs provide frequency range information. It can also be used as a ultrasound mic with a OTG cable (£2) to a mobile device (i.e. exactly like a Griff).
- Bring along three AAA batteries (rechargeable are fine)
- mini PiPistrelle quick start guide
Advanced – Ultrasound recorder building Workshops
In these advanced workshops we build ultrasound recording devices that can be used to record the sounds of bats, mammals, birds… etc. Due to the more complex build, and much longer testing required, the Advanced Ultrasound Recorder workshops are usually 4 hours long.
If you have some experience of electronic component assembly, or have successfully completed a standard workshop, then these two devices are possible.
- π•pistrelle – The same features as the mini but adds recording. Materials cost = £22
Full-spectrum recording is to a mSD card, and the ability to set a GPS location is via the App. This can either be one off recording, or in overnight mode. It can also be used as a ultrasound mic (i.e. like a Griff).
The build has more components and the mSD card holder is a tricky placement, hence the “more experienced” recommendation. - PippyG – Is a full spectrum recorder, with no audio out. Materials cost = £20
Designed specifically for overnight bat recording or bird/mammal recording. It has fewer configuration options than the similar sized AudioMoth making deployment via the App. much easier. Slightly different in size to the AudioMoth means that no commercial cases are currently available. However the workshop leader can show DIY weatherproof options from £3.
These both take three AA batteries (rechargeable are fine), and also bring along a ExFat formatted mSD card. They both are configured via the Pipistrelle phone App (iOS or Android).
When can I build one?
The next workshops are:
28th Feb 2026 – Bat Detector Workshop
This is a private workshop for Norton and Chiselborough Nature Network. However depending on the numbers taking part from the group, there may be spaces available to Bat Group members. Email us to be added to the waiting list.
- Local village hall at 1:30 to 4:30PM
SPRING 2026 – Bat Detector Workshops
- We are planning more workshops at Somerset Wildlife Trust Offices in Taunton and Avalon Marshes in March/April 2026. Details will be published early in 2026
If you can’t make these dates, and there is more demand, we will book venues for workshops in locations nearer to you. Perhaps you can get a local group of you together? Simply drop us a email to register your interest, please say which model of detector you are interested in building, and what’s your nearest town – somersetbatgroup@gmail.com
All the future workshop dates will also be on the events page of our website.