Sheet 01 · Wireless Signal Range Mapper
Sketch the walls. Place the access point. Read the heat.
WSRM is a small, honest instrument for home and small-office network tinkerers. Draw a floor plan, set down up to three access points, and see an approximate Wi-Fi signal heat map in dBm before you drill a hole or buy a second box.
Figure 1 · Live demo
Move over the plan, or focus it and use the arrow keys, to read the signal.
Example flat, 20 × 12 m, drawn with the same engine as the mapper. Drag the numbered disc to move the access point. With the keyboard: arrow keys move the cursor (hold Shift for bigger steps), Enter moves the access point to the cursor. The rings are a pulse, which stops if your system asks for reduced motion.
Bench procedure
Three moves, in the order a lab notebook would list them. Each one has a pointer way and a keyboard way, so nothing here needs a mouse.
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Sketch
Pick a wall material, then drag across the plan. Prefer the keyboard? Arrow keys move a cursor, Enter drops the first end, Enter again finishes the wall and carries on from there.
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Place
Drop up to three access points and drag them around. Each placement sends a ripple of new heat across the plan, so you can see what the move changed.
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Read
Hover or arrow-key anywhere. The readout panel gives the dBm, a named quality band, the serving access point, the distance and the walls crossed. Export the lot as a PNG.
Instrument specification
What the tool does, stated plainly so you can judge how far to trust it.
- Model
- Log-distance path loss from each access point, plus a fixed loss for every wall that the straight line to the point crosses.
- Bands
- 2.4, 5 and 6 GHz, modelled at centre frequencies of 2437, 5500 and 6500 MHz.
- Walls
- Six materials: glass, drywall, wood, brick, concrete and metal. Each loss value is editable.
- Access points
- One to three. Every point on the map shows the strongest of them.
- Plan sizes
- 12 × 8 m, 20 × 12 m or 30 × 18 m. Drawing snaps to 0.5 m; the heat is sampled every 0.25 m.
- Output
- A dBm readout, coverage percentages at three thresholds, and a PNG export with legend and caveat.
- Privacy
- Your plan stays in this browser, saved only if the browser allows it. Nothing is uploaded.
Who it is for
People who like to understand the thing before they move the thing: home networkers, small-office admins, and anyone whose router lives behind the television for reasons nobody remembers.
- Where should the router go?Try the hallway, the living room and the cupboard on the same plan and compare the coverage percentages.
- Is a second access point worth it?Add one in the far bedroom and watch the weak patch shrink, or fail to.
- Which wall is the villain?Change one material’s loss and see how much of the map hangs on that single wall.
- 2.4, 5 or 6 GHz?Flip the band and see the trade between reach and speed-friendly bands, wall by wall.
Honest limits
This is an approximation, not a survey. The map shows the likely shape of coverage under a simple model. It does not measure your building, and it cannot promise a speed or a signal level in any room.
Use it to compare options and to decide where to test first. Then walk the space with a real signal meter or your own devices before you commit to cable runs or a purchase.
What the model leaves out
- Reflections, diffraction around corners and doorways, and other multipath effects.
- Furniture, appliances and people, beyond the single clutter setting.
- Floors and ceilings: the plan is one flat level.
- Antenna patterns and orientation; every access point radiates equally in all directions.
- Interference from neighbours, microwave ovens and other radios.
- Client devices, which differ in sensitivity and in how they choose an access point.
- Local transmit-power rules; you set the number, WSRM does not check it.
Put the instrument on the bench
The example flat is already loaded, so you can start by moving one access point and watching what happens. Clear the walls when you are ready to draw your own.