Laser detector: when it is essential, where to get one

What exactly is a detector for?

The detector travels along a staff or a rule and reports, by arrows and a tone, whether it sits above, below or exactly on the line. It turns a line you can no longer see into a reading you can follow.

It is the only way to work with a laser outdoors in daylight, and the quickest way to work in a large space.

Where to get one from us

We do not sell the detector separately: you tick it in the box, on the laser’s own page. Only our two lasers with green 360° planes offer it, because a detector makes sense only with an instrument that has pulse mode. It is added as an option, and the order ships as one parcel:

• Laser level, 12 green lines at 360° — three complete planes;
• Laser level, 16 green lines at 360° — four planes, two of them horizontal.

On both pages, the “Make up your box” block offers the 50 m detector as an option. The price shown updates, and the order stays one line, one reference, one parcel.

The reason is simple: a detector is only worth the pair it makes with its laser. Sold in the same box, that pair is backed by the manufacturer — there is no compatibility left to check.

Why is pulse mode compulsory?

A detector is not looking for “light”: it is looking for light that flickers at a set frequency, which is how it tells it apart from the sun and from the room lighting. The laser level must therefore emit in pulse mode, and both our 360° instruments state that they do.

With pulse mode switched off the detector picks up nothing — and that is not a fault.

What range should you expect?

A stated range is always given “in good conditions”. On site it depends on the sun, on the power of the laser and on how steady the mounting is. A line that reads perfectly in a corridor can vanish in full sun, with nothing about the instrument having changed.

On both our 360° lasers the manufacturer states 20 m by eye and up to 50 m with the detector. That is the order of magnitude to remember: the detector does not double the range, it multiplies it by two and a half — and above all it makes the range usable in full sun, where the figure by eye falls to almost nothing.

What counts in use?

The mounting first: a solid clamp and a standard thread let the detector go on a staff or a rod. Then the display: a reading visible from several sides saves walking round the mounting. Last the audible alarm, essential in a noisy place — and the automatic cut-off, which stops you finding a flat battery the next day.

And if you already have a laser

We no longer offer the detector on its own. If your current instrument has a pulse mode and you are after the detector alone, the question to put to your supplier is the stated instrument-and-detector pair: it is the only assurance worth having, since beam colour and modulation frequency have to match.

To set the instrument at the right height, look at tripods and poles, and for choosing the laser itself, our guide.