The Swift Caller Project
The Swift Caller is a fully automated playback system designed to support conservation efforts by attracting Swifts to new nesting sites.
Born from a collaboration between Draco, the Sanquhar Men's Shed, and conservation expert Andrew Turney, this project aims to replace expensive commercial units with an accessible, community-driven solution.
The system features our custom "Click & Connect" modular design—a weather-resistant (PETG/ABS) enclosure that snaps together without complex wiring. This allows other Men's Sheds and conservation groups to utilize our Development Kits to build their own reliable, solar-powered units that can survive the harsh Scottish weather.
Sustainability Model: To ensure the project's longevity, i license the firmware for a nominal fee (approx £3-£5 per unit). This covers the server costs for updates and support, while 100% of the remaining proceeds go directly to funding the Sanquhar Men's Shed non-profit activities.
Project Gallery
The Prototype
Early bench testing of the ESP32-C3 and audio amplifier setup.
DEVKET-1 (Development Kit)
The modular electronics kit designed for other Sheds to experiment with safely.
Full Unit Assembly
Our custom weather-resistant PETG housing design, ready for outdoor deployment.
The Mission & The Story
The Spark: It all began when fellow Shedder Andy Williamson attended a talk by local conservation enthusiast Andrew Turney. Inspired by the plight of the Swift—a bird that travels an astonishing 7,000 miles from Africa only to find its UK nesting sites disappearing—Andy invited Andrew to our Shed. That meeting was the catalyst for me. We realized that while the Shed had the woodworking skills to build the nest boxes, we needed a way to actually attract the birds to them.
Intergenerational Innovation: This project became a perfect example of how our Shed works. While Andy led the construction of the wooden nesting boxes, the technical challenge fell to me. My goal was to design an electronic caller that could mimic the "screaming" calls of Swifts to encourage them to investigate new sites. But it couldn't just be a prototype; it had to be solar-powered, weather-resistant, and capable of surviving the Scottish summer without needing constant maintenance.
The Solution ("Click & Connect"): Drawing on the need for simplicity, I wanted to move away from fragile wiring and developed a modular "Click and Connect" system. At the heart of the unit is my custom SC-MPU (Swift Caller-Main Processing Unit), powered by an ESP32-C3. I’ve pre-programmed this "brain" to handle the audio schedules and power management, allowing other Sheds to assemble the kit using just a screwdriver—no soldering required.
Looking Ahead: With Swifts returning in May, the race is on. Our goal is to have the first batch of units and Developer Kits ready for our annual coffee morning. By making the technology accessible, I hope to empower Sheds across Scotland to start their own local "Swift Mapper" networks and help reverse the decline of these extraordinary birds. As I mentioned to the Scottish Men’s Sheds Association recently: "The caller can actually be adapted for use with other bird species too," making this a versatile tool for future conservation.
SC-MPU Tech Specs
Core MicroProcessor: ESP32-C3
Power Module: TP4056 5V
Audio AMP: MAX98357 Amp (Mono)
MPU Housing Material: PETG Plastic
Wiring: 20 AWG
Other Tech Specs
Power input: USB/5V Solar/18650 Li-Ion
Speaker: 2831 4ohm 3W Speaker
Full Unit Material: ABS Plastic
How to Order / Get Involved
Development Kit
£25
/Unit
Full Technical Support
Software Customization Support
Indoor tested only.
Full Unit
£35
/Unit
Limited Technical Support
No Software Customization
Tested outdoors
Interested in obtaining a unit?
As we are currently in the Alpha Phase of development, we are not yet accepting automated online orders. However, we are building units manually to order for local community groups and individuals.
You can place an order by visiting us in person or getting in touch via email.
Resources & Downloads
| Resource Name | Type | Version | Action |
|---|---|---|---|
Swift Audio Pack (High Quality) |
Audio (.mp3) | v0.0 | |
Assembly Manual & Guide |
Document (.pdf) | v0.0 | |
SwiftCaller Firmware |
Binary (.bin) | Alpha 0.0 | |
3D Print Files (STL) |
Zip Archive | v0.0 |
Development Roadmap (2025/2026)
Concept & Inception
Identified the need for a cost-effective, automated caller to support the swift conservation efforts. Initial sketches were created for a "modular" system designed to replace expensive units. The core requirements were established: the unit had to be
- Lightweight and durable
- Easy to install and maintain
- Has it's own file system (No SD card required)
- Doesn't need to be connected to a network for operation
- capable of fully powering itself via solar energy and battery
Aug 2025
Prototype V0 ("The Breadboard")
After several weeks of research, the initial electronic breadboard was completed.
We benchmarked multiple microcontrollers and selected the ESP32-C3 for its power efficiency and low cost.
Early bench testing paired the ESP32 with the MAX98357 I2S amplifier, successfully proving that high-fidelity digital audio could be played via a low-cost microcontroller.
Sep 2025
Prototype V1 - First Housing
Following the success of the electronics test, we began construction of the first "Version 1" physical prototype.
This was the first iteration of the weatherproof design, featuring a custom 3D-printed enclosure.
Side Note: The first case was printed in PLA on a friend's printer. This process actually sparked my own interest in additive manufacturing, leading me to acquire a Bambu Lab P1S to bring the production in-house.
Oct - Nov 2025
The Glenkens Meeting
Visited the Glenkens Men's Shed and met with "Swift Guy" Andrew Turney.
The project received a very positive response and was granted an official "Green Light" to proceed.
Based on Andrew's direct feedback, we committed to the "Click and Connect" modular design to make the Development units accessible for other Sheds to build.
Dec 2025
The "Soak Test" (Weather)
We deployed the V1 prototype for a field test during heavy winter rain.
The Failure: The PLA plastic casing degraded and warped under the elements, causing moisture ingress and loose wiring.
The Fix: Production was immediately shifted to PETG and ABS materials for superior weather resistance.
We also moved from breadboards to soldered connections for all final units.
Early Jan 2026
Sanquhar Committee Approval
Presented the updated plans to the Sanquhar Men's Shed Committee. Addressed concerns regarding WiFi interference (confirmed non-issue) and finalized the pricing model: £25 for Dev Kits and £30-£35 for full units.
Late Jan 2026
Alpha Build & Supply Chain
Sourcing components for the Alpha run while battling a 2-week shipping delay on Li-Ion cells.
Current Focus: Assembling the DEVKET-1 bags and preparing the final units for Andrew Turney's final review after Feb 14th.
Feb 2026
Production Run
Production run for the Sanquhar Men's Shed begins. 3D printing cases, soldering connections.
Mar 2026
Launch Deadline
The Birds Arrive. Get units ready for sale at the coffee morning before the Swifts return in late April.
Early April 2026
About Me
I'm Draco, a passionate developer focused on creating innovative and enjoyable projects. Let's connect and collaborate!
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