Fazley RabbiA device that works on a desk can fail within weeks on a factory roof, beside a pond or in a poultry shed. In Bangladesh, the usual causes are not software bugs but the environment: strong sun, dust, constant humidity, monsoon rain, flooding, lightning and an unstable power supply. The good news is that most of these failures are predictable. The right enclosure, power design, mounting and maintenance routine prevent the majority of them.
Heat
What goes wrong. Electronics have an operating temperature range. A sealed plastic box in direct sun can get much hotter than the air around it. Batteries age faster in heat, and some lose capacity or swell. A temperature sensor inside a hot box reports the box, not the room.
What helps.
- Mount devices in shade, or add a sun shield with an air gap behind it.
- Choose light-coloured, UV-resistant enclosures; cheap plastic can turn brittle in the sun.
- Pick components and batteries rated for the conditions, and check the datasheets rather than assuming.
- Place external sensors away from the electronics and from heat sources such as motors or tin roofs.
Dust
What goes wrong. Fine dust from roads, rice mills, brick kilns, textile mills and feed factories gets into connectors, fans and openings. It blocks sensor vents, holds moisture, and can cause short circuits over time.
What helps.
- Use enclosures with a suitable IP rating. The IP code has two digits: the first describes protection against dust and solid objects, the second against water. Ask your supplier what the rating means for your particular site.
- Seal cable entries with proper cable glands instead of drilled holes and tape.
- Avoid fans where possible. If a sensor needs airflow, use a protective cover or filter that can be cleaned.
Humidity and condensation
What goes wrong. Humid air enters a box, cools at night, and condenses into droplets on the circuit board. Over weeks this corrodes connections. Sealed boxes are not immune: moisture gets in through cables and small gaps, and then cannot get out.
What helps.
- Fit a breathable vent made for enclosures, which lets air pressure equalise without letting water in.
- Add desiccant packs, and replace them during maintenance.
- Ask for conformal coating, a thin protective layer, on circuit boards used in damp sites.
- Leave a drip loop in every cable, so water runs off before it reaches the entry point.
Monsoon, flooding and lightning
What goes wrong. Heavy rain finds every weak seal. Floodwater reaches devices mounted low. Lightning and grid surges travel along power lines and long sensor cables.
What helps.
- Mount devices above the highest water level you have seen, with a margin.
- Point cable entries downwards.
- Use surge protection on power lines and, where cables run long distances outdoors, on signal lines too. Earthing and surge protection should be designed and installed by a qualified electrician.
- Prefer wireless links for long outdoor runs where practical, to avoid long cables that pick up surges.
Power cuts and unstable voltage
What goes wrong. Load-shedding, voltage drops and spikes when a generator starts can reset devices, corrupt memory or damage power supplies. A device that does not restart cleanly after a power cut may stay offline until someone visits.
What helps. A good power supply with protection, a battery or supercapacitor for a clean shutdown, and firmware that recovers on its own. The IoT power and backup design article goes into this in detail.
Installation habits that prevent trouble
- Label each device and cable, and note its location and installation date.
- Fix devices firmly; vibration loosens connectors over time.
- Keep devices out of reach of animals and curious hands, and protect cables from rats.
- Set up an "offline" alert, so a dead device is noticed within hours, not weeks.
A simple maintenance calendar
- Monthly: check the dashboard for gaps, drifting readings and devices that restart often.
- Before the monsoon: inspect seals, glands and vents; replace desiccant; check mounting heights.
- After storms: visit outdoor devices and check for water inside and surge damage.
- Before summer: clean dust from vents and sensors, and check the sun shields.
- On a fixed schedule: check sensors against a reference instrument; see sensor accuracy and calibration.
Before rolling out many devices, run a small trial through at least one hard season, as described in starting with an IoT pilot. If you want devices designed for your site, see the IoT development service.