Attagram Technical Architecture
Published April 14, 2026
Attagram is a small Wi-Fi thermal printer that brings the kitchen-counter note across any distance. Adults write a note from anywhere; it prints on paper at home; the kid keeps it.
This page describes the product’s hardware design and the standard technologies it is built from. We believe in building in the open, and we publish this so other engineers and product designers can understand what we built and what we built it with.
Product description
Attagram is a compact consumer appliance containing a 58mm thermal printer and a Wi-Fi microcontroller inside a 3D-printed enclosure. An adult sends a message from a companion mobile app; the message is delivered via a cloud service to the device, which prints it on phenol-free thermal paper (no BPA or BPS). The recipient reads the printed note without using any screen or electronic device.
Hardware components
| Component | Specification |
|---|---|
| Microcontroller | ESP32-C3 SuperMini |
| Thermal Printer | 58mm ESC/POS-compatible module |
| Power Supply | 5V 3A UL-listed USB-C wall adapter + USB-C cable |
| Enclosure | 3D-printed body with magnetic front panel (neodymium magnets) |
Standard technologies used
Attagram is assembled entirely from standard, well-documented technologies and engineering patterns. The following table lists each technology area, what standard or existing implementation it follows, and representative references.
| Technology Area | Standard / Pattern | References |
|---|---|---|
| Thermal printing protocol | ESC/POS (Epson Standard Code for Point of Sale) | Epson ESC/POS Command Reference (publicly available since 1980s); implemented by Star Micronics, Bixolon, HPRT, and hundreds of third-party manufacturers |
| Wi-Fi microcontroller | ESP32-C3 (Espressif Systems) | Espressif ESP-IDF framework; Arduino-ESP32 open-source project |
| WiFi provisioning | SoftAP captive portal | Espressif ESP-IDF provisioning examples; tzapu/WiFiManager library (40k+ GitHub stars); used by virtually every consumer WiFi IoT device |
| Device-to-cloud communication | WebSocket (RFC 6455, 2011) | IETF standard; used by AWS IoT Core, Azure IoT Hub, Google Cloud IoT |
| Transport encryption | TLS 1.2+ (RFC 5246) | Industry standard; implemented via mbedTLS (bundled with ESP-IDF) |
| Device authentication | HMAC-SHA256 challenge-response (RFC 2104, 1997) | Foundational network security pattern; used by AWS Signature V4, MQTT brokers, most IoT platforms |
| Device pairing | “Display code, enter elsewhere” pattern | Used by Google Chromecast (2013), Apple TV, Amazon Echo, Bluetooth PIN pairing; our variation prints the code on paper instead of displaying on a screen |
| Firmware updates | Signed OTA with hash verification | Espressif ESP-IDF OTA documentation; AWS IoT Device Management; NIST SP 800-147; OWASP IoT Security guidelines |
| Factory reset | Rapid power-cycle detection | Standard consumer IoT pattern; used by TP-Link Kasa, Philips Hue, Tuya-based devices, and many smart home products |
| Power distribution | Single 5V rail with bulk capacitor for line smoothing | Standard electrical engineering practice; described in Horowitz & Hill, The Art of Electronics; recommended in thermal printer application notes |
| Raster image handling | 1-bit bitmap manipulation | Standard computer graphics; ESC/POS raster commands documented in Epson’s public command reference |
| Build configurations | Conditional compilation (#ifdef) | Standard embedded development practice; supported by PlatformIO, ESP-IDF, Arduino, GCC, and every major toolchain |
Enclosure design
The enclosure is a compact housing containing the thermal printer, microcontroller, capacitor, and a paper roll compartment. The front panel attaches via magnets for tool-free paper replacement. A panel-mount USB-C passthrough is mounted on the rear. The paper exits through a slot at the front.
This is a straightforward enclosure design using off-the-shelf hardware (M3 standoffs, panel-mount USB-C jack, cylinder magnets).
Published by Halfcorp, LLC on April 14, 2026. The engineering approaches described here are standard, well-documented techniques available to anyone. Attagram trademarks and branding remain the property of the author.