
I Just Wanted a Button. It Escalated.
I was tired of smart bulbs needing complicated apps or voice assistants, so I decided to build my own DIY smart button from scratch. What started as a simple idea quickly spiraled out of control into designing custom PCBs! In this video, I bypass bloated stacks like ESP32, WiFi, Zigbee, and Bluetooth entirely to create a custom wireless solution. By using an nRF52 microcontroller and a standard CR2032 coin cell battery, I managed to optimize the power consumption down to 1.4 microamps. This gives the button a theoretical battery life of 9 years! But I didn't stop at just a button. By keeping the low-power "button-like" architecture, I accidentally built an entire smart home sensor kit! You'll see how I adapted this core board to work with: - An accelerometer for a laundry machine motion sensor. - A hall effect sensor for a magnetic door switch. - A PIR motion sensor. - A quadrature encoder knob for dimming and volume. - A temperature and humidity sensor. - An e-ink display for weather and reminders. Open Source Links: - Documentation / Code / Electronics: https://github.com/dennisss/dacha/tree/master/pkg/things/button/index.md - 3D Printing Files: https://www.printables.com/model/1672648-wireless-smart-buttons-sensors Chapters: 0:00 Intro 1:20 Plan 1:43 Microcontroller 6:12 Waking Up 9:39 Wireless Protocol 11:53 Encryption 16:25 Battery 19:50 Battery Life 20:42 Putting Everything Together 23:59 I can’t believe it's not button! 28:41 Bonus Features 30:28 Conclusion Corrections: 26:46 You can get normally closed (NC) reed switches that avoid this problem so only consume power when a door is open. Links: - Microcontroller I Am Using (in the final board): https://www.digikey.com/en/products/detail/u-blox/bmd-380-a-r/12759179 - USB Dongle I use for development: https://www.mouser.com/ProductDetail/Nordic-Semiconductor/nRF52840-Dongle - Other beginner friendly NRF board I recommend: https://www.adafruit.com/product/4481 (try out the "Learn" pages) - Microcontroller Datasheet: https://docs.nordicsemi.com/bundle/ps_nrf52840/page/keyfeatures_html5.html - Power Profiler: https://www.nordicsemi.com/Products/Development-hardware/Power-Profiler-Kit-2




















