Overview & Our Mission
The Spark: The Nest Link (formerly 'Swift Caller') started as a rescue mission for the Common Swift. It was born from a collaboration between Draco, the Sanquhar Men's Shed, and local enthusiast Andrew Turney. After learning that swifts travel 7,000 miles from Africa only to find their UK nesting sites rapidly disappearing, we realized that building wooden nest boxes wasn't enough—we needed a way to actually attract the birds to them.
The Solution (Phase 1): Frustrated by ridiculously expensive commercial audio lures, we set out to build an accessible, autonomous alternative. The result is a highly effective, "Set and Forget" caller that survives Scottish weather and manages its own audio schedules via a custom ESP32-C3 brain. For the 2026 season, we are rolling out our Alpha Phase: deploying rugged, made-to-order Solar and USB-C units to gather rigorous field feedback before a wider rollout.
Looking Ahead (Phase 2): We refuse to release a product that isn't bulletproof. Once our audio callers are completely stabilized, our next major step will be integrating nest cameras to allow communities to visually monitor the wildlife that our callers successfully attract.
Hardware Specs
Core: ESP32-C3 Microprocessor
Power: USB / 5V Solar / 18650 Li-Ion
Audio: MAX98357 Amp (Mono) w/ 3W Speaker
Housing: Weather-resistant PETG / ABS Plastic
Big Thank You
- Will: For 3D printing the V1 prototype cases.
- Nitro: My partner & constant motivation.
- Neil: Battery donations & project support.
- Andy: For the original idea & nesting boxes.
- Andrew: Practical field experience & swift expertise.
- Sanquhar Men's Shed: Funding, tea, and support.
How to Order / Get Involved
The Off-Grid Caller
Solar Edition
£35
/Unit
Fully autonomous solar power
Includes 18650 Li-Ion cell
Mount anywhere (no plugs needed)
Weatherproof & outdoor tested
30-Day Shed Warranty
Available from March 2026
Made to order
The Window Caller
Early Alpha Phase
USB-C Edition
£25
/Unit
Continuous USB-C power
No internal batteries to fail
Perfect for near-socket mounting
Standard firmware pre-loaded
Full technical support
Available Late 2026
Delayed so we can focus on the solar unit this year!
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.
Visit Us
Sanquhar & District Men's Shed
St Brides Church Hall,
St. Mary's Street
Sanquhar
DG4 6BW
Shed Opening Hours
| Day | Time |
|---|---|
| Monday | 10:00am - 12:00pm |
| Wednesday | 10:00am - 12:00pm & 7pm - 9pm |
| Friday | 10:00am - 12:00pm |
Resources & Downloads
The Market Comparison
We believe in radical transparency. Here is a totally honest look at how our non-profit Shed units stack up against everything else currently on the market—from £8 DIY hacks to £200+ ecological equipment.
| Feature | Swift Caller (Solar) | Swift Caller (USB-C) | Basic MP3 Module | Typical Commercial Lure | Pro Conservation Lure | DIY 12V Car Amp Setup | DIY Bluetooth Speaker |
|---|---|---|---|---|---|---|---|
| Average Retail Price (2026) | £35 | £25 | £30 | £60 - £120+ | £120 - £250+ | £40 - £60 | £15 - £30 |
| Estimated Parts Cost | ~£15 - £25 (High-Quality) | ~£12 - £20 (High-Quality) | ~£8 (SV5W chip) | ~£10 - £15 (Mass-Produced) | ~£30 - £50 (Ruggedized) | ~£40 (eBay Parts) | N/A (Retail Item) |
| Markup / Profit Margin | £0 Profit (Shed Buffer) | £0 Profit (Shed Buffer) | ~275% Private Profit | 300% - 800% Corporate | High Ecology Markup | N/A (You build it) | N/A |
| Automation | Smart Set & Forget | Smart Set & Forget | Basic Continuous Loop | Usually Automated | Advanced Scheduling | Needs plug-in timer | Requires Manual Pairing |
| Configuration UI | DIP + Wi-Fi Portal | DIP + Wi-Fi Portal | USB / SD Card Swapping | Fiddly DIP Switches | PC Software via USB | None | Phone App Required |
| Audio Hardware | I2S Digital Amplifier | I2S Digital Amplifier | Low-end SV5W chip | Basic Analog Amp | High-End Audio | Loud but noisy car amp | Compressed Bluetooth |
| Power Management | Deep Sleep / Solar | Mains USB-C | Always On (Battery drain) | Basic Light Sensor | Expensive D-Cell Batteries | Needs heavy 12V Leisure Battery | Needs Daily Charging |
| Repairability | 100% Modular | 100% Modular | Usually DIY Friendly | Sealed Unit (Disposable) | Factory Service Required | 100% DIY Parts | Sealed Unit (Disposable) |
| Profits To Charity | Yes (Men's Shed) | Yes (Men's Shed) | Private Profit | Corporate Profit | Corporate Profit | N/A | Corporate Profit |
| Availability / Lead Time | Built to Order (Slower) | Built to Order (Slower) | Usually Built to Order | Next-Day Delivery | Usually In Stock | Instant (If you have parts) | Instant In-Store |
| Initial Setup Complexity | Connect to Wi-Fi portal | Connect to Wi-Fi portal | Load MP3s onto SD card | Plug & Play / Physical switch | Advanced PC Setup | Extreme (Wiring nightmare) | Standard Bluetooth pairing |
| Aesthetic Finish | Visible 3D Print Lines | Visible 3D Print Lines | Basic DIY Junction Box | Smooth Injection Molded | Heavy Duty Factory Casing | Loose messy wires | Factory Finish |
The Verdict |
Best if: You want an autonomous, off-grid solution and don't mind a slightly bulkier 3D-printed unit. |
Best if: You have a nearby plug socket, want zero battery maintenance, and prefer a lighter unit. |
Best if: You want a budget, dedicated physical unit but don't mind lower audio quality or a lack of smart scheduling. |
Best if: You want next-day delivery, a sleek factory finish, and don't care about extreme price markups. |
Best if: You are a well-funded ecology department that requires industrial-grade ruggedness. |
Best if: You love tinkering with 12V car audio and don't mind having messy wires trailing out a window. |
Best if: You just want to test if swifts are around for an afternoon using gear you already own. |
Fact-Check Us (Reference Links)
Curious to see exactly what we are comparing the Swift Caller against? Here are real-world examples of the other methods used across the conservation community:
Transparency: Where does the money go?
We hate it when people are ripped off by commercial wildlife gear. Some "branded" bird callers cost upwards of £60 despite containing barely £15 worth of parts. Here is the exact, honest breakdown of what it costs us to build the Swift Caller:
| Electronics
Main Processing Unit (MPU)
|
~£12.19 |
| 3D Housing (Weather-resistant ABS) | £7.29 |
| Consumables (Solder, Sealant, Screws) | ~£0.60 |
| Draco's Service Fee (Software, 3D Printer Upkeep) | £5.00 |
| Shed Buffer / Donation | ~£9.92 |
| Total Price | £35.00 |
Project FAQ & Insights
Development Roadmap
Inception & Early Prototypes
Sparked by a conversation with Andy Williamson, the goal was set to build a solar-powered Swift Caller to pair with the Shed's nesting boxes. We benchmarked microcontrollers, settling on the highly efficient ESP32-C3 paired with a MAX98357 I2S amplifier. By Autumn, the first V1 physical prototypes were being 3D-printed in PLA.
Summer & Autumn 2025
The "Soak Test" & The Glenkens Meeting
Met with swift enthusiast Andrew Turney, who gave the project an enthusiastic green light, cementing our decision to design a "Click & Connect" system.
However, winter field testing revealed a major flaw: the PLA plastic casing degraded and warped under heavy Scottish rain.
The Pivot: Production was immediately shifted to weather-resistant PETG and ABS materials, and the Sanquhar Committee officially approved the £35 pricing model.
Winter 2025 / 2026
Alpha Production Run
Overcoming a two-week shipping delay on Li-Ion cells, the initial production run for the Sanquhar Men's Shed began. Cases were printed, components were soldered, and the first batch of fully sealed units was assembled.
March 2026
Deployment & Firmware V002
A massive month for the project! We successfully delivered a batch of black A1 units to Andrew Turney for specialized conservation field testing. Simultaneously, the green Shed unit was mounted on the stone walls of St. Brides Church Hall.
Firmware V002: a major firmware update introducing Light Sleep overnight hibernation, drastically improving battery life, alongside a massive overhaul of the Web UI with uptime tracking, volume sliders, and dynamic CPU scaling.
April 2026
Active Field Testing Season
The Birds Return. The callers will run autonomously throughout the summer. This season is strictly dedicated to gathering data on unit stability, solar efficiency, and bird interaction rates across the Sanquhar and other testing sites.
May - August 2026 (Current)
DEVKET-1 Public Launch
Using the data and firmware stability achieved during the 2026 test season, the modular "Click & Connect" Development Kits are targeted to officially launch, allowing other Men's Sheds across Scotland to easily build their own callers.
Early 2027
About Me
I'm Draco, a passionate developer focused on creating innovative and enjoyable projects. Let's connect and collaborate!
Get in touch
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