$30 Homebrew Automated Blinds Opener (2024)

Original Article ↗ Hacker News Discussion ↗

Motor torque sensing: current vs direct measurement

  • Several comments debate whether motor current is a good proxy for torque.
  • One side: current sensing is “good enough” and widely used in industry; with motor constants, resistance, voltage, and gear ratio you can derive torque, at least relatively.
  • Other side: with high gear ratios and cheap gearboxes, current–torque correlation becomes poor; friction, temperature, and mechanical slop dominate, so you only get a vague “effort” signal, not accurate torque.
  • Series-elastic mechanisms and direct torque sensing are presented as more reliable but more complex/expensive.

Child and general safety with blinds

  • Key risks called out: pulling the unit off the wall, strangulation on cords, fingers caught in mechanisms, and electrical hazards for powered systems.
  • Standards such as UL 325 are mentioned as important; commenters stress that safety comes from process and adherence to standards, not intuition.
  • One person describes an intentionally “overbuilt” but toddler-safe mechanical opener using a weight and solenoid, with all moving parts out of reach.

Value of automated blinds and home automation philosophy

  • Many describe bedroom blinds automation as unusually high “quality of life” for the price: consistent wake times, no daily cognitive load, and strong effect on mood vs artificial light.
  • Others note it’s not useful if they sleep with masks or pillows over their heads.
  • Repeated advice: good automation should augment, not replace, manual controls. Smart switches that still work offline and automations that don’t break basic usability are praised.
  • Some argue most “control-by-app” setups are regressions; real automation is schedules, occupancy, and state-based rules that usually require no interaction.

Blackout vs light management

  • Strong interest in full blackout for kids or shift workers; basic vinyl blinds are considered inadequate.
  • Suggested solutions: blackout curtains (often double-rod with “pretty” outer curtains), internal blackout roller/honeycomb shades with side channels, “blockout” or “blackout thermal” blinds, European rolling shutters, and sleep masks.
  • Sleep masks receive detailed endorsements from people extremely sensitive to light; others prefer to wake with sunlight and see darkness + alarms as worse.
  • Temporary hacks include aluminum foil and painter’s tape, especially for travel.

Home automation stacks and tooling

  • Home Assistant (including the dedicated hardware box) is repeatedly recommended as the central platform.
  • Common integrations: Zigbee/Z-Wave smart plugs and switches, Hue/ IKEA lighting, ESPHome DIY sensors, MQTT, and external tools like PyScript, AppDaemon, and Node-RED for more complex logic.
  • Example automations: air-quality-triggered fans, porch lights on schedules, circadian lighting, low-level night lights, temperature-controlled window A/C, and alerts when appliances (e.g., humidifiers) stop drawing power.

Commercial and alternative blind/shutter solutions

  • Multiple off-the-shelf retrofits are mentioned:
    • Clip-on blind tilters (e.g., SwitchBot Blind Tilt) with solar charging and optional hubs.
    • Motor units like Ryse SmartShade for roller shades, integrated with Home Assistant.
    • 3D-printed gearboxes that sit inline with the blind shaft, using servos and ESPHome.
  • For European-style exterior rolling shutters, commenters reference motorized versions (“tapparella motorizzata”) plus in-wall Wi-Fi relays (e.g., Shelly) to integrate with automation.

Thermal control and building design

  • Automated blinds are also valued for passive temperature control: closing during hot sunny periods, especially on south-facing windows.
  • Some argue interior blinds only partly help; exterior shading (awnings, overhangs, external shades, climbing plants) can be much more effective.
  • German-style rolladen and well-designed roof overhangs are cited as powerful combined solutions for seasonal sun management.

DIY mains work and safety concerns

  • One commenter harshly criticizes the article’s mains-side design (relay doubling, resistor from mains to logic, questionable connectors), calling it dangerous and likely to cause fire or insurance problems.
  • Others push back that DIY learning is important, but agree high-voltage work demands more than trial-and-error and should start from solid understanding of creepage/clearance, isolation, and code.
  • There’s broad agreement that mistakes with mains pose risks not just to the builder but to others and future occupants, and that low-voltage experimentation is the safer entry path.