Posts Tagged ‘raspberrypi’
[NDCOslo2024] Building a Robot Arm with .NET 8, Raspberry Pi, Blazor and SignalR – Peter Gallagher
Amid the mesmerizing merger of microcontrollers and modern markup, Peter Gallagher, a prolific .NET pioneer and podcast personality, prototypes a pivotal plaything: a prehensile prosthesis powered by Pi, .NET 8, Blazor’s bounty, and SignalR’s synergy. As the mind behind “The .NET Core Podcast” and a maestro of minimal viable marvels, Peter parades the panoply—from GPIO gymnastics to VR vistas—proving platform potency in playful pursuits. His hands-on homage, humming with hardware harmony, heralds hobbyists to harness high-level harmony for haptic happenings.
Peter polls the populace: Raspberry aficionados abound, yet arm artisans are scarce—his spur to share schematics, sans soldering sermons. .NET 8’s native nod to ARM architectures animates accessibility, eclipsing esoteric embeds.
Wiring the Wonder: GPIO and Servo Symphonies
Genesis germinates in GPIO groundwork: Pi’s pins, PWM-proficient, pulse servos to swivel shoulders, elbows, wrists. Peter parades the paraphernalia: SG90 servos, jumper joys, breadboard bastions—budget below 50 quid.
Code commandeers: Iot.Device.Bindings beckon, Servo class summoning sweeps—angle aspirations from 0 to 180. Peter’s prototype: console commands calibrating claws, clutching candies in cinematic clips.
Blazor’s Bridge: Browser-Borne Brawn
Blazor bridges the breach: WebAssembly wielding webcams, SignalR streaming signals—real-time relays routing remote reaches. Peter’s portal: Razor renders ranges, sliders summoning servo shifts; hubs herald hubbub, harmonizing host and handler.
He highlights hitches: CORS courtesies, container conundrums—Pi’s paucity of ports prompting proxies. Yet, yields yield yawns: yawns of yawp, where web wielders wrench wrenches wirelessly.
VR’s Vanguard: Questing for Quarters
Quest 3 quests quaternary: Unity unleashes OpenXR, hand-tracking hailing haptics—gestures grasping grippers. Peter’s phantasm: VR viewport voyaging Pi’s panorama, passthrough peering at prehensile prowess.
Integration ignites: SignalR surges selections, servos saluting salutes—synthetic senses simulating seizures. Peter’s plea: print, procure, partake—his GitHub grotto granting guides.
Horizons of Hardware: Harmonizing Hopes
Peter’s panegyric: .NET’s ubiquity unlocks universes—embedded epics, VR ventures—vitalizing visions. His valediction: venture ventures, validate validations—birthday bonuses beckon bold builders.
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[DevoxxFR2015] Reactive Applications on Raspberry Pi: A Microservices Adventure
Alexandre Delègue and Mathieu Ancelin, both engineers at SERLI, captivated attendees at Devoxx France 2015 with a deep dive into building reactive applications on a Raspberry Pi cluster. Leveraging their expertise in Java, Java EE, and open-source projects, they demonstrated a microservices-based system using Play, Akka, Cassandra, and Elasticsearch, testing the Reactive Manifesto’s promises on constrained hardware.
Embracing the Reactive Manifesto
Alexandre opened by contrasting monolithic enterprise stacks with the modular, scalable approach of the Reactive Manifesto. He introduced their application, built with microservices and event sourcing, designed to be responsive, resilient, and elastic. Running this on Raspberry Pi’s limited resources tested the architecture’s ability to deliver under constraints, proving its adaptability.
This philosophy, Alexandre noted, prioritizes agility and resilience.
Microservices and Event Sourcing
Mathieu detailed the application’s architecture, using Play for the web framework and Akka for actor-based concurrency. Cassandra handled data persistence, while Elasticsearch enabled fast search capabilities. Event sourcing ensured a reliable audit trail, capturing state changes as events. The duo’s live demo showcased these components interacting seamlessly, even on low-powered Raspberry Pi hardware.
This setup, Mathieu emphasized, ensures robust performance.
Challenges of Clustering on Raspberry Pi
The session highlighted configuration pitfalls encountered during clustering. Alexandre shared how initial deployments overwhelmed the Raspberry Pi’s CPU, causing nodes to disconnect and form sub-clusters. Proper configuration, tested pre-production, resolved these issues, ensuring stable heartbeats across the cluster. Their experience underscored the importance of thorough setup validation.
These lessons, Alexandre noted, are critical for constrained environments.
Alternative Reactive Approaches
Mathieu explored other reactive libraries, such as Spring Boot with reactive Java 8 features and async servlets, demonstrating versatility beyond Akka. Their demo included Gatling for load testing, though an outdated plugin caused challenges, since resolved natively. The session concluded with a nod to the fun of building such systems, encouraging experimentation.
This flexibility, Mathieu concluded, broadens reactive development options.
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[DevoxxBE2012] Home Automation for Geeks
Thomas Eichstädt-Engelen and Kai Kreuzer, both prominent figures in the open-source home automation scene, presented an engaging exploration of openHAB. Thomas, a senior consultant at innoQ with expertise in Eclipse technologies and OSGi, teamed up with Kai, a software architect at Deutsche Telekom specializing in IoT and smart homes, to demonstrate how openHAB transcends basic home control systems. Their session highlighted the project’s capabilities for geeks, running on affordable devices like the Raspberry Pi while offering advanced features such as presence simulation, sensor data visualization, and integration with calendars.
They began by challenging common perceptions of home automation, often limited to remote light switching or shutter control via smartphones. Kai and Thomas emphasized openHAB’s open-source ethos, allowing extensive customization beyond commercial offerings. The framework’s modular architecture, built on OSGi, enables easy extension to connect with diverse protocols and devices.
A live demo showcased openHAB’s runtime on embedded hardware, illustrating rule-based automation. For instance, they configured scenarios where motion sensors trigger lights or simulate occupancy during absences. Integration with Google Calendar for irrigation scheduling demonstrated practical, intelligent applications.
Thomas and Kai stressed the project’s appeal to Java and OSGi enthusiasts, featuring an Xbase-derived scripting language for defining complex logic. This allows developers to craft rules reacting to events like temperature changes or user inputs.
Core Concepts and Architecture
Kai outlined openHAB’s structure: a core runtime managing bindings to hardware protocols (e.g., Z-Wave, KNX), persistence services for data storage, and user interfaces. Bindings abstract device interactions, making the system protocol-agnostic. Persistence handles logging sensor data to databases like MySQL or InfluxDB for historical analysis.
Thomas highlighted the OSGi foundation, where bundles dynamically add functionality. This modularity supports community-contributed extensions, fostering a vibrant ecosystem.
Advanced Automation and Integration
The duo delved into rule engines, where scripts automate responses. Examples included voice commands via integrations or mobile apps notifying users of anomalies. They showcased charts displaying energy consumption or environmental metrics, aiding in optimization.
Integration with external services, like weather APIs for proactive heating adjustments, illustrated openHAB’s extensibility.
User Interfaces and Accessibility
Kai demonstrated multiple UIs: web-based dashboards, mobile apps, and even voice assistants. The sitemap concept organizes controls intuitively, while HABPanel offers customizable widgets.
Thomas addressed security, recommending VPNs for remote access and encrypted communications.
Community and Future Developments
They noted the growing community, with over 500 installations and active contributors. Future plans include simplified binding creation guides, archetypes for new developers, and enhanced UIs like MGWT.
In Q&A, they discussed hardware support and integration challenges, encouraging participation.
Thomas and Kai’s presentation positioned openHAB as a powerful, developer-friendly platform for innovative home automation, blending Java prowess with real-world utility.