Challenging Hardware Contests with Zephyr and Lessons Learned 

About Me Handle name：　misoji @misoji_engineer Occupation: Hardware Engineer. I am a Hardware and Hobbyist Engineer This presentation is about My Hobby. (Not work-related!) 

Agenda • My Initial Experience with Zephyr • Zephyr in Recent Hardware Contests • Lessons Learned from the Contests • Presenting at the Zephyr Project Meetup in Japan • Summary An Introduction to Hardware Contests with Zephyr 

My Initial Experience with Zephyr 

Zephyr Beginner I'm a "Beginner" who just started this year. How I Got Started with Zephyr? + + I had no experience with Zephyr(RTOS). 

Hardware Contests introduced me Recently, seeing more contests involving Zephyr. Through Hardware contests + + Custom PCBs 

Zephyr in Recent Hardware Contests 

2025　Hardware Contest Board Designer Competition https://www.hackster.io/contests/board-designer Restraint to Reinvention https://www.hackster.io/contests/Restraint2Reinvention The Power Hop Challenge https://www.hackster.io/contests/ribbithop BLE Audio Design Challenge https://www.hackster.io/contests/SonicSprint Edge AI Earth Guardians https://www.hackster.io/contests/earthguardians 2025 Pet Hacks Challenge https://hackaday.io/contest/202866-2025-pet-hacks-challenge One Hertz Challenge https://hackaday.io/contest/203248-one-hertz-challenge 　　　　　2025 Configurable Logic Design Challenge　 https://www.microchip.com/en-us/campaigns/clb-design-challenge STM32 Edge AI Contest https://www.elektormagazine.com/stm32ai Hardware Development Contests There are many hardware contests around the world. These are just a few examples. 

Contests involving Zephyr Contest Sponsors and themes are involved with Zephyr https://www.hackster.io/contest s/board-designer 　　　　　　 https://www.hackster.io/contests/earthgu ardians https://www.hackster.io/conte sts/ribbithop 　　　　　　 https://www.hackster.io/contests/ SonicSprint　 https://www.hackster.io/contes ts/Restraint2Reinvention https://www.elektormagazine.c om/stm32ai https://www.allaboutcircuits.com/giveaways/2025-n xp-design-contest-using-nxps-frdm-i-mx-93-board/ https://www.hackster.io/contests /InfineonMLModel Nordic is a key sponsor. Infineon is a key sponsor. STMicroelectronics is a key sponsor. NXP is a key sponsor. Low power is one of the theme. Big Contributors with Zephyr. 

If possible, I'd like to join all of them... I participated in three contests in 2025 https://www.hackster.io/contest s/board-designer 　　　　　　 https://www.hackster.io/contests/earthgu ardians https://www.hackster.io/conte sts/ribbithop 　　　　　　 https://www.hackster.io/contests/ SonicSprint　 https://www.hackster.io/contes ts/Restraint2Reinvention https://www.elektormagazine.c om/stm32ai https://www.allaboutcircuits.com/giveaways/2025-n xp-design-contest-using-nxps-frdm-i-mx-93-board/ https://www.hackster.io/contests /InfineonMLModel Nordic is a key sponsor. Infineon is a key sponsor. STMicroelectronics is a key sponsor. NXP is a key sponsor. Low power is one of the theme. Timeline: Jan-May 2025 Timeline: Mar-Jun 2025 Timeline: Jul-Sep 2025 

Implement Zephyr I’ll explain my contest projects in detail... Maker's nRF54L15 Debug Board https://www.hackster.io/iotengineer22/maker-s- nrf54l15-debug-board-1a6a88 Adaptive Directional BLE Audio Speaker https://www.hackster.io/iotengineer22/adaptive- directional-ble-audio-speaker-2d892d Edge AI on Zephyr: ULP Acoustic Monitoring for Wildlife https://www.hackster.io/iotengineer22/ed ge-ai-on-zephyr-ulp-acoustic-monitoring-f or-wildlife-e31cdd + + + Zephyr on All projects 

Hardware Contest_1 Board Designer Competition 

Board Designer Competition ■Contest Overview ・Good proposals received $200 for PCB fabrication. ・Using sponsor-designated theme ICs and tools earned more points 　　→ "Nordic nRF54L15 SoC" was one of themes. Nordic's Wireless SoC was one of the themes (Complete the project) Not Win... Jan-May 2025 Board Designer Competition https://www.hackster.io/contests/board-designer Maker's nRF54L15 Debug Board 

nRF54L15 + Zephyr ■Nordic Wireless SoC nRF54L15 High-Performance, Low-Power IoT Applications with Zephyr https://www.nordicsemi.com/Products/nRF54L15 https://www.zephyrproject.org/ ■Open-Source Zephyr(RTOS) + ・Cortex-M33_128MHz ・256KB_RAM / 1.5MB_Flash My first experience 

Maker's nRF54L15 Debug Board Benchmarked an evaluation board featuring the nRF54L15. Official board: nRF54L15-DK Project URL: https://www.hackster.io/iotengineer22/maker-s-nrf54l15-debug-board-1a6a88 My Development Board 

Demo Video https://youtu.be/hCGmB4HsRTw 

Good Point About Zephyr_① Plenty of interface samples for custom board. ■ The official samples from Zephyr and Nordic https://github.com/zephyrproject-rtos/zephyr/tree/main/samples https://github.com/nrfconnect/sdk-nrf/tree/main/samples I just modified 

Good Point About Zephyr_② Easy Wireless Communication (e.g., Bluetooth Low Energy). ■We could easily achieve microsecond-level synchronization using the Bluetooth LE sample. Less than 1us 

Good Point About Zephyr_③ Zephyr(RTOS) runs perfectly fine, even on RISC-V ■Zephyr supports many architectures(ARM, RISC-V, x86…). 

Hardware Contest_2 BLE Audio Design Challenge 

BLE Audio Design Challenge ■Contest Overview ・A call for project proposals using Bluetooth LE Audio. ・Projects had to include "Nordic nRF5340　SoC" + "Nordic PMIC". ・Proposers with good designs received full funding for PCB fabrication. The contest theme was "Bluetooth LE Audio". Won! 1st Prize I did it! Mar-Jun 2025 BLE Audio Design Challenge https://www.hackster.io/contests/SonicSprint Adaptive Directional BLE Audio Speaker 

Adaptive Directional BLE Audio Speaker Transmitter and Speaker System for Bluetooth LE Audio Project URL: https://www.hackster.io/iotengineer22/adaptive-directional-ble-audio-speaker-2d892d SOC (nRF5340) PMIC (nPM1300) *BLE…Bluetooth Low energy Audio IC (CS47L63) My Development Board 

Demo Video https://youtu.be/sZ_NohyZeC0 

Good Thing About Zephyr ④ ■Like Unicast and Broadcast, simultaneous transmission of audio to multiple devices. 　 "BLE Audio" requires high sync → Match for Zephyr. 

Good Thing About Zephyr ⑤ Easily implemented on both Official and Custom Boards. nRF5340 評価ボード Official boards: nRF5340 Audio DK Samples: ・CMakeLists ・Kconfig ・devicetree Custom Boards: Implemented on nRF5340 I just modified 

Good Thing About Zephyr ⑥ Zephyr supports a huge number of boards. Nordic nRF54L15 DK Nordic nRF5340 Audio DK Raspberry Pi Pico2W NXP FRDM-RW612 Seeed nRF54L15 (nRF52840) Sense I tested Many boards this year. Raspberry Pi Pico 

Hardware Contest_3 Edge AI Earth Guardians 

Edge AI Earth Guardians ■Contest Overview ・Looking for projects featuring “Low-power consumption” and “Edge AI”. ・Any environmental theme is okay, such as "preventing wildlife poaching". Hosted by the Edge AI Foundation. Theme is ’Environment’. Aug-Sep 2025 Edge AI Earth Guardians https://www.hackster.io/contests/earthguardians Edge AI on Zephyr: ULP Acoustic Monitoring for Wildlife (Complete the project) Not Win... 

ULP Acoustic Monitoring for Wildlife Audio recognition using Zephyr + Edge AI Project URL: https://www.hackster.io/iotengineer22/edge-ai-on-zephyr-ulp-acoustic-monitoring-for-wildlife-e31cdd Japan has faced a growing conflict between humans and wildlife. Especially Bears.. *ULP…Ultra Low Power 

Demo Video https://youtu.be/C1XkCEpDAo8 

Good Thing About Zephyr ⑦ Low-Power Ecosystem using Zephyr, even with Edge AI. ■Zephyr can achieve Low(uA) current consumption. 

Good Thing About Zephyr ⑧ ■My example project(GitHub) zephyr-ei-xiao-nrf-demo: https://github.com/iotengineer22/zephyr-ei-xiao-nrf-demo pico2-ei-zephyr-demo: https://github.com/iotengineer22/pico2-ei-zephyr-demo Major AI frameworks(TFLite-Micro, Edge Impulse…) support. SDK, Parameter, Model for Edge AI Zephyr Project https://edgeimpulse.com/ https://www.zephyrproject.org/ Just Build it all together. 

XIAO nRF54L15 Sense ・Cortex-M33_128MHz ・256KB_RAM / 1.5MB_Flash XIAO nRF52840 Sense ・Cortex-M4F_64MHz ・256KB_RAM /1MB_Flash + Good Thing About Zephyr ⑨ Zephyr fits in small RAM and ROM. ■Including the AI model, fits into kilobytes of RAM and ROM.　 Low-end SoCs/CPUs 

Presenting at the Zephyr Project Meetup in Japan 

Zephyr community in Japan I want to learn more, and also share what I know. Zephyr is still early stages in Japan. But... Hey, let me in! 

Zephyr Project meetup: Sapporo ■Zephyr Recap Blog: https://www.zephyrproject.org/recap-blog-zephyr-project-meetup-sapporo-japan/ Japan's first official meetup took place in Sapporo. ・July 4, 2025 ・Venue provided by Space Cubics Thank you! “Space Cubics” 

Zephyr Project meetup: Osaka ■Zephyr event: https://zephyrproject.org/event/zephyr-project-meetup-osaka-japan/ The second meetup was also held in Osaka recently. ・October 20, 2025 ・Honda Software Studio Osaka Zephyr Project Thank you! “HONDA” 

Zephyr RTOS User Group - Japan Discord (#Japanese channel) Good Thing About Zephyr ⑩ There are strong local communities everywhere. https://zephyr-rtos.connpass.com/ https://chat.zephyrproject.org/ Thank you! Good Community 

Summary 

・Match for embedded & IoT devices. 　(It works great with Bluetooth, Audio, and Edge AI.) ・An easy RTOS to implement on Hardware(Contest). 　(It's open-source and supports a wide range of boards.) ・Why not become my rival in a Hardware contest? (Hardware contests are tough, but also a lot of fun.) Summary Through a hardware contest, I experienced how great Zephyr！ 

In Closing Thank you for your attention. I'm also presenting at 17:30～. Check it out if you can! Lightning Talk: Debugging Edge AI on Zephyr and Lessons Learned 

Q&A Example:1 Question Answer What was the most difficult part? Contest: The tight deadlines were hard because I have limited time as a hobbyist. Zephyr: Understanding the configuration system (CMakeLists, prj.conf, Device Tree) was tricky at first. But once I learned the basic West commands, I could write C/C++ code normally. What are the benefits of using Zephyr? 1. Small Size: Zephyr fits on small SoC easily (low RAM/ROM usage). 2. Hardware support: It supports many boards, giving lots of choices. 3. Rich libraries: Libraries for interfaces and wireless make creating hardware demos very easy. Advice for beginners implementing Zephyr? 1. Copy and modify: Copy the reference board's schematic, config, and Device Tree from the IC maker, then modify them. 2. Use recommended tools: Use the manufacturer's recommended IDE (e.g., "nRF Connect for VS Code" for Nordic). What Zephyr feature do you want to try next? I want to test inter-core communication (IPC, OpenAMP). Many recent SoCs, like the nRF54L15 and Pico 2, have multiple cores. Is building for RISC-V difficult? It is not difficult. You just need to specify the target core in the west build command (e.g., select "cpuapp" for Arm or "cpuflpr" for RISC-V). “west build -p always -b xiao_nrf54l15/nrf54l15/cpuapp(cpuflpr) samples/hello_world” 

Q&A Example:2 Question Answer How was the Edge AI accuracy? Simple words or motions worked well with minimal data(About 1 minutes). However, bear sounds had many false positives due to a lack of samples. I recommend starting with large open datasets (like TensorFlow Lite Micro speech examples). https://github.com/tensorflow/tflite-micro/tree/main/tensorflow/lite/micro/examples/micro_speech How do you find these contests? I usually find them on technical websites, like Hackster.io. When did Zephyr contests become popular? I think about 1 or 2 years ago. Sponsors like Nordic are hosting more contests where Zephyr is featured