Pre-Renovation Profile
A two-storey detached house in Bangkok’s Thonburi side, building age 22 years. Ground floor elderly bedroom: 4×4.5 metres (18 sqm), 2.6m ceiling height, laminate flooring with 8-year aging showing cracking and surface peeling. Ensuite bathroom 2×2 metres, 70cm door, no grab rails, no Smart systems. Resident: grandmother, age 78, with hypertension and knee degeneration — alone during daytime while her child works.
Phase 1: Universal Design Retrofit — 28,500 THB (3 Weeks)
Bedroom floor replaced from laminate to matte SPC Flooring COF 0.65, light grey, 18 sqm: materials 9,500 + labour 4,500 THB, 2 days. Bathroom door changed from 70cm hinged to 90cm sliding door (better waterproofing, easier to open with limited strength): materials + labour 8,500 THB. Stainless 304 grab rails installed in bathroom — horizontal beside the toilet at 460mm height, diagonal in the shower: materials + labour 4,500 THB. Bathroom walls repainted from plain white to white-grey contrast to clearly define floor-wall edges: 1,500 THB.
Phase 2: Smart Sensor Suite — 21,000 THB (1 Week)
mmWave 60GHz mounted on bedroom ceiling centre at 2.6m, covering the full 4×4.5m area: device 5,500 + wiring 1,500 THB. mmWave mounted in bathroom upper corner covering the 2×2m area: device 4,500 + wiring 800 THB. SHT31 Temperature + Humidity Sensor on bedroom wall at 1.5m height: 450 THB. NDIR CO₂ Sensor on bedside table: 2,800 THB. IP67 Panic Buttons in bathroom and bedside plus bathroom Pull Cord: 2,500 THB total. Raspberry Pi 4 Home Assistant Hub with 32GB SD Card: 3,200 THB.
Phase 3: Smart Lighting — 6,800 THB (2 Days)
All bulbs replaced in bedroom (4) and bathroom (2) with Zigbee Smart Bulbs supporting 2700K–6500K Color Temperature and 1–100% Dimming: 3,600 THB. Smart Night Light Motion Sensors along bedroom-to-bathroom corridor (2 points): 2,000 THB. Home Assistant Automation programming and labour: 1,200 THB.
Phase 4: Communication and Emergency — 9,500 THB (3 Days)
Smart Lock on ground floor bedroom door with PIN + RFID + App: device + labour 7,000 THB. Bedside Smart Speaker for Voice Control and reminders: 1,500 THB. Full LINE Notify Alert configuration and scenario testing: 1,000 THB.
Total Project Budget
Phase 1: 28,500 + Phase 2: 21,000 + Phase 3: 6,800 + Phase 4: 9,500 = 65,800 THB total. Duration: 5 weeks.
90-Day Outcomes
The grandmother reported feeling significantly more at ease when alone. Her daughter noted a clear reduction in anxiety about her mother. Over 90 days, the mmWave system sent 2 real alerts: Alert 1 — grandmother slipped mildly in the bathroom, recovered independently, but the system alerted her daughter who called back immediately and visited. Alert 2 — CO₂ exceeded 1,000 ppm in the bedroom from an overly sealed room; the system notified her to open the window. Both events were managed before escalating.