Noise and dust
sensor

Continuous noise and dust measurement at urban works sites. Off-grid, pole-mounted, moved from site to site.

What it measures

Why it is built this way

Round pole · 2 brackets · 2 clamps. Solar panel toward the sun.

1. 

   Check the kit: two brackets, four screws and four hex nuts.

2. 

   Place one bracket across the two top feet and one across the two bottom feet, open side away from the sensor.

3. 

   Push each screw through the bracket slot and the foot, then fit a hex nut on the front of the foot. Tighten the four nuts. Do not overtighten: the feet are plastic.

4. 

   Thread a clamp through a slot in each bracket. Pick the slot that lines up with the pole.

5. 

   Wrap both clamps around the pole and thread each one back through its bracket.

6. 

   Turn the solar panel toward the sun. Hold the sensor against the pole and tighten both clamps with the 8 mm nut driver.

Shipping mode

Leaves shipping mode at first power: supplied power supply, or solar panel in daylight.

Power supply

When it sends data

Sending times, local time. Daylight only, to match the solar panel's energy.

Bluetooth

Use central.semitronica.pt on site, next to the sensor, to check it works.

1. Phone or laptop with Bluetooth and a supported browser (table below). An Android phone with Chrome is easiest on site.
2. Sensor charging. Bluetooth is on only while it charges: plug in the power supply, or check the solar panel is in daylight.
3. Stand next to the sensor. Bluetooth reaches a few metres.

1. 1

   1Open central.semitronica.pt. Click the Bluetooth icon next to SENSORS.

2. 2 3

   2Select ESENSE-… in the list.
   3Click Pair, then enter PIN 555555.
   No ESENSE in the list? Check the sensor is charging and you are next to it, then wait: on some devices this takes a few minutes.

3. 4 5

   4Connected shown: the sensor works.
   5Serial Number matches the label (ASENSE21S00004).

1. 1 2

   1Paste your API key in ACCESS KEY.
   2Click Access Dashboard.

   3

   3Browser asks to save it: click Save. Next time the key is filled in.

2. 4

   4Select Environmental Monitoring.

Now: latest record

A B C D E

A

System status Time since the last data packet. Daytime: under 2 h.

B

Particulate matter PM1, PM2.5, PM10 in µg/m³ and particles/cm³, with air-quality band.

C

Noise level Average and peak of one 10 s capture per record.

D

Battery State of charge, last 72 h.

E

Dust sensor obstruction Warning if the optical window is blocked.

Navigation

1 2 3 4

1

Target device 00001 = sensor ASENSE21S00001.

2

Core Now: latest record. Month: data availability.

3

Environmental Particulate Matter, Noise Level: charts and tables.

4

Time range Month shown on every page. This month = current.

Month: data availability

▦

Rows = days, columns = hours (UTC). Green = records received; darker = more (6 per hour = complete). Hover a cell for its times.

Particulate Matter

A B C D E F

A

Unit µg/m³ (mass) or n/cm³ (particle count).

B

Series Click to show or hide PM1, PM2.5, PM10.

C

Obstruction Readings with a blocked window are left out, shaded red.

D

Zoom Drag the handles to pick a time window.

E

Export Month data as JSON or CSV.

F

Readings One row per 10 min record, newest first.

Noise Level

A B C D E F

A

Weighting dB(Z): unweighted, all frequencies. dB(A): weighted like human hearing.

B

Average · Peak Green: average level. Red dashed: peak level. Both from one 10 s capture.

C

Values Hover the chart: time and both levels of that record.

D

Zoom Drag the handles to pick a time window.

E

Export Month data as JSON or CSV.

F

Readings One row per 10 min record: average and peak in dB(Z) and dB(A).

Gaps in the chart = no records for that time.

Find the symptom. Try the fixes in order, top to bottom.

Query parameters

Request

curl -sG "https://api.semitronica.pt/asense/v2/" \
  -d "table_name=env" \
  -d "id=ASENSE21S00002" \
  -d "start_time=1791364200873" \
  -d "end_time=2000000000000" \
  -H "x-api-key: YOUR_API_KEY"

{
  "data": [
    {
      "id": "ASENSE21S00001",
      "time": 1791364200873,
      "datetime": "2026-10-07T09:10:00.873000Z",
      "pm1_ug/m3": 8.0,   "pm1_/cm3": 64.0,
      "pm2_5_ug/m3": 8.0, "pm2_5_/cm3": 66.0,
      "pm10_ug/m3": 8.0,  "pm10_/cm3": 66.0,
      "spl_avg_db": 60.0,
      "spl_pk_db": 69.0,
      "is_ob_ov": 0,
      …
    },
    …
  ],
  "next_timestamp": 1791620399612
}

Measurements

Hardware

Power and communication