Problem Statement

Procuring electronic components, precision sensors, solar cells, and lab test instruments from global suppliers is frequently hamstrung by punitive international bank wire charges, SWIFT fees, and credit card gateways that devour 30% to 50% of small donations (€1 to €10). Furthermore, traditional crowdfunding platforms pool money into opaque, non-itemized buckets with zero visibility into how donations translate into actual parts. This sprout builds a sovereign, self-hosted micro-donation infrastructure dedicated to direct line-item sponsorship from open Bill of Materials (BOM) specs.

Open Hardware Bill of Materials (BOM Hints)

  • Host Server Hardware: Low-power single-board computer (ODROID-C4 or Raspberry Pi 4 with 4GB RAM) equipped with an external 500GB NVMe SSD over USB 3.0 for sustained node operations.
  • Software Stack: Self-hosted BTCPay Server instance orchestrating Dockerized daemons; Core Lightning (CLN) / LND node with local liquidity management; pruned Monero node for donor privacy.
  • Interactive Lab Terminal: Espressif ESP32 with a 3.5-inch SPI capacitive touch display (ILI9488) rendering instant on-counter QR payment invoices and triggering addressable LEDs on the matching physical parts drawers.
  • Cryptographic Cold Storage: SeedSigner or Coldcard hardware wallet for air-gapped signing of liquidity rebalances; zero private treasury keys reside on the internet-facing server.

Schematics & Experiment Notes

  1. Zero-Fee Lightning Micropayments: Leveraging the Bitcoin Lightning Network to process payments under €1.00 with sub-2-second settlement and network routing fees below €0.001. A supporter can directly sponsor a single €0.50 connector or €6 transceiver without bank fees eroding the contribution.
  2. Itemized BOM Sponsorship Targets: Each component from our open KiCad schematics is mapped to an interactive sponsorship target:
  3. Connectors, TVS diodes, and passives: €0.50 – €2.00
  4. Semtech SX1262 LoRa module: ~€6.00
  5. Synchronous MPPT controller IC: ~€12.00
  6. 3.2V 100Ah LiFePO4 battery cell: ~€38.00
  7. 1kg UV-resistant PETG/ASA filament spool: ~€18.00
  8. Automated Public Accounting (Git-backed Ledger): BTCPay Server webhooks automatically push cryptographically signed commits to a public Git repository (ledger.git), updating inventory levels in real time and publishing scanned supplier receipts immediately after procurement.
  9. Zero Intermediary Dependency: No commercial merchant accounts, zero commission cuts to Stripe or PayPal, and zero risk of arbitrary financial freezes during international solidarity campaigns.

Call for Contribution (How to Join)

  • Frontend Developers: Help us build a zero-dependency, ultra-lightweight JavaScript widget to render dynamic BOM items and invoice QR codes without external bloat.
  • Lightning Node Operators: Open direct liquidity channels with our lab node to enhance routing connectivity across the South-Eastern European mesh.
  • Open Hardware Makers: Connect your local open-source hardware projects to our platform to enable itemized component micro-funding for your prototypes.