Ultrasonic Measuring Devices

[tpaul]

I got the Fein version of an Ultrasonic tape measure and find it useless. It is consistantly inconsistant. Even at 8ft height across an open plan office its results vary. Measurements from one side of the room differ from the other side.

Its not a question of pointing it right as it comes with a laser spot.

What width is the sonic cone or what sort of angle does it subtend ?

Have I got a duff one or are they all the same ?

Bosch make one that utilises the laser to take the measurement, but £280 ? How good are these ?

Or Leica at about £750 ? I suppose given its parentage this would be the dogs proverbials.

Paul Mc Cann

[MrCheerful]

I had a stanley us measure which I returned, I now have a cheapy maplin one which is better but only good for a quick estimate, the results are reasonably reliable but not really accurate.

MrCheerful

[Harry Bloomfield]

[e-mail] explained :

I have an old (very) Plasplugs one. It works quite well providing the measuring path is unimpeded. Accuracy seems to be quite good.

[nightjar]

They are intended as estimating devices, good for people like estate agents, but you should not expect to get very accurate measurements from the ones in general use. They also need to work off a hard, vertical surface on the other side of the room. Avoid aiming them near anything, curtains, soft furnishings, sound absorbing office partitions, that might interfere with a clean return of the sound.

Colin Bignell

[Peter Taylor]

Harry Bloomfield wrote

Speaking as someone who spends a lot of time measuring buildings, you would think these gadgets would be very useful for me. We gave them a good trial in the 80's and came to the conclusion they are far too unreliable for anything requiring a moderate amount of accuracy. The main problem is the inconsistent results. You can never have any faith in the thing and you are never exactly sure what you are really measuring. Maybe a laser spot might get over that but I still wouldn't trust it. There are also severe limitations - e.g. how do you measure between two external corners, like the width of a chimney breast for example, or the width/height of a door leaf?

The only people I know who find them useful (who certainly don't seem to mind too much about accuracy), are estate agents :o)

Peter

[Wanderer]

I used to carry one for measuring the height of overhead conductors. That had a very small beam spread, and was accurate, in relative terms, to within a couple of centimetres at anything up to 10 to 15 metres. I occasionally checked it's accuracy with glass fibre measuring rods.

[nightjar]

That sounds about right and it was no doubt perfectly acceptable for the purpose. However, I wouldn't class an error that is worse than one part in

1,000 as more than moderately accurate.

Colin Bignell

[tpaul]

sorry about the double post. Ive ben trying out Gravity newsreader and it didn't appear to be posting my meassages. Switching back to Agent for a peek it now appears it was posting them.

Doh !

Paul Mc Cann