SmartAngle® projects

Important note:

The presence of a project on this page does not imply that it will be manufactured and sold by QUS or any other company.

We are always interested in ways in which SmartAngle can be used so please contact us if you have found a new use for SmartAngle - photos of your application would be appreciated.

On this page

The drawings on this page were produced using the free SketchUp CAD software which may be downloaded as "SketchUp Make" from

SmartAngle family

The image above shows SmartAngle at the heart of a family of products:

  1. The SmartAngle app on an iPhone.
  2. Digital levels: 600mm, 400mm, 300mm - other lengths could be available.
  3. SmartAngle CLL - Cross Line Laser - more details on the SmartAngle page.
  4. SmartAngle itself.
  5. Clamp for holding SmartAngle to edges.
  6. Angle of incidence meter for radio controlled aircraft.
  7. Control throws meter for radio controlled aircraft.
  8. Engine downthurst and sidethrust meter for radio controlled aircraft.
  9. Protective metal case with foam insert.

Our technology in other products

SmartAngle is an example of the way angle measurement may be integrated into a product.

We can develop prototypes for other types of implementation very quickly including:

  • Electronics design and development up to fully working PCBs.
  • Various sensors and communications methods including: angle measurement, Bluetooth, WiFi, etc.
  • Processor selection and firmware.
  • App development for Apple iOS and Android - as well as software for Windows and Apple PCs.

Please contact us with a brief outline of what you would like and we will respond by return.

Note: we are happy to work under non-disclosure terms if requested.

SmartAngle with power tools

SmartAngle's small size and light weigh make it ideal for temporary fitting to power tools to ensure accurate angles for drilling, sawing, cutting etc. In most cases a simple adapter, or a glued-on steel strip, is all that is necessary to enable SmartAngle to fit magnetically.

On a cordless drill

In this case an adapter containing a 45mm x 12mm x 1mm metal strip fits to the back of the battery pack. The adapter means that SmartAngle can be fitted and removed in a second while the drill will still stand upright on the battery as a base if required.

On this cordless drill the back of the battery pack is is not perpendicular to the drill axis but SmartAngle can be zeroed at the true vertical position.

From then on the SmartAngle app displays the angular offset of the drill - ideal for drilling vertical or horizontal holes - or any angle in between.

The adapter fits the space occupied by the label on the back of the battery. The steel strip allows SmartAngle to fit magnetically.

The side walls ensure that SmartAngle is aligned properly.

Free download

An alternative mounting system puts SmartAngle flat against the base of the battery pack.

For those with access to a 3d printer the two adapters shown here are available as STL (stereolithography) files for free download. You will need to fit (with glue or double-sided tape) a steel strip to the slot provided in the adapter.

Perfect vertical holes - every time!

On a table saw

SmartAngle has been fitted to the saw blade to adjust the angle of cut.

The photograph below was taken by the app while connected to SmartAngle. The current angle, along with a date and time stamp, are automatically superimposed on the image.

Adding SmartAngle to other projects or products

SmartAngle is very small (approx. 67mm wide x 41mm tall x 17mm deep) and very light (less than 30g) making it ideal for integrating into projects and products that require accurate angle measurement.

You can make a project "SmartAngle compatible" in at least three ways.


The SmartAngle enclosure includes two 12mm OD x 1mm circular rare earth magnets along with a 45mm x 12mm x 1mm steel strip to "amplify" their effect.

SmartAngle will "stick" to any steel surface.

For non steel surfaces it is recommended to glue a 45mm x 12mm x 1mm steel strip in a suitable place as is done with levels and the Incidence Meter.

With a pocket

A pocket may be machined to hold the SmartAngle enclosure which is 17mm deep.

The drawing procedure is:

  1. Draw an isoceles right angled triangle with 60mm short sides.
  2. Create parallel lines 8mm in from all three sides. They will cross at the locations of the 3mm screw holes.
  3. Draw a line 2mm below and parallel with the long side of the triangle - this allows for the space taken by the internal magnets.
  4. Use this line to create a slightly larger isoceles right angled triangle.
  5. Add 6mm fillets to the corners of this larger triangle.

Using screws

See the drawing above for the locations of the 3mm screw holes.

Use screws which reach into the nylon threads but ensure that they are not too long. Do not over tighten them or the nylon threads will be damaged.

Example: radio controlled model aircraft

A set of adapters contains all the elements for setting up a remote controlled model aircraft.

SmartAngle's small size and light weight (under 30g) makes it ideal for this job.

Important note

QUS does not manufacture or sell these parts. We may consider injection moulding the parts if there is sufficient demand to justify the cost of tooling.

Please contact us if you fancy manufacturing these parts and selling them commercially as an aero modelling aid alongside SmartAngle.

The drawings below were produced using the free SketchUp CAD software.

An extension for .STL export is available from the SketchUp Extension Warehouse which may be reached from one of the menu lists in the software.

  • Click here to download the free "SketchUp Make" software for PC or Apple Mac.
  • Click here to download the SketchUp drawing for these adapters.
  • Click here to download the .STL 3d printing file for these adapters.

SmartAngle fits magnetically using a strip of 45mm x 12mm x 1mm sheet steel glued in place. This is the same size as the steel strip inside SmartAngle itself. See the photo above.

Measuring angle of incidence

The "angle of incidence" (sometimes incorrectly called the "angle of attack") is the angle at which a wing is mounted relative to the horizontal axis of an aircraft's fuselage. This angle is critical to give the maximum amount of lift with the minimum amount of drag.

The "arms" slide to accomodate wings of different widths and the jaws rotate to allow for wing taper. This version is 300mm long but uses standard 3/4" x 3/4" x 1/16" aluminium "T" profile so any length can be created.

Click here for the 3/4" x 3/4" x 1/16" aluminium T profile.

Click here for M5 knurled thumb screws.

Click here for M5 threaded inserts to take the thumb screw. These can be pressed in place using a soldering iron.

Click here for M4 x 20mm machine screws and nuts.

Other sources for T profile, thumb screws, threaded inserts, screws and nuts may be found on ebay or Aliexpress.

The photo below shows SmartAngle being used with a newly assembled Chris Foss WOT 4 radio controlled model aircraft.

This model has a symmetrical wing (the curved shape on top is the same as that underneath) so the angle of incidence should be zero. The wing is not yet bolted down which accounts for the one degree reading. An aircraft with a symmetrical wing is as happy flying upside down as the right way up - assuming the operator does not confuse "up" with "down"!

Measuring control surface throws

Just as with full size aircraft it is important that the control surfaces (ailerons, elevator, rudder etc.) move by the correct amount in each direction - and this is usually measured in degrees.

We designed a clip to hold SmartAngle to control surfaces - a strip of steel is embedded into the top surface of the clip - but it can also be held in place by putting a magnet under the surface. For this we recommend using a strong Neodymium rare earth magnetic such as those available from eMagnets.

The clip requires a thin metal rod through the centre and a suitable spring such the ones on these bulldog clips on ebay

The images below show the clip attached to the elevator of the same Chris Foss WOT 4 radio controlled model aircraft.

The procedure is simple:

  • Fit the clip to the control surface and place SmartAngle on top
  • Set the surface to the neutral position (no up or down.)
  • Connect SmartAngle to the app.
  • Click the "Zero" button in the app to set this as the zero angle for reference.
  • Use the transmitter to move the surface up or down - the SmartAngle app shows the movement in degrees.
  • Set the limits on the transmitter to the angles you want.

SmartAngle measures angles in degrees, ratios or slopes (millimetres per metre or inches per foot). Control surface throws are sometimes expressed as the amount of movement of the trailing edge (Xmm up, Ymm down etc.) This is not directly measured by SmartAngle because it doesn't know the width of the control surface.

The angle of movement, "A", can be calculated by taking the atangent of the up or down movement, "M", divided by the control surface width, "W". So, A = atan ( M / W ).

The free "RealCalc" calculator for Android and Apple iOS is excellent for this type of calculation. Calculate M/W then use "Shift" "Tan" to calculate the angle as an atangent.

The rudder is left/right rather than up/down so the model will need to be held at 90 degrees to set the rudder throws.

Measuring engine down thrust and side thrust

Engines for Radio Controlled aircraft are fitted with a small amount of down and side thrust - this is measured in degrees.

Down thrust (pointing the engine slightly downwards when mounted in the model) ensures that the aircraft does not climb when power (thrust) is increased.

Side thrust (pointing the engine slightly in the opposite direction to the rotation of the propellor) compensates for the fact that the whole aircarft wants to rotate (turn) in the direction of rotation.

We have made an adapter that bolts to the propellor shaft of an engine. The main part contains a steel strip to hold SmartAngle in place magnetically. The smaller part is an insert that can be drilled out to the diameter of the propellor shaft - 1/4" UNC in the case of this Irvine 39 ABC two stroke engine.

The photos below show the principle of use - in this case the engine is in an engine mount rather that being installed in a model aircraft.

Obviously, to measure side thrust, the model, with the engine installed, would be held at 90 degrees.

Example: suspension setup

A simple adapter with an embedded steel strip makes SmartAngle ideal for setting up the different angles involved in suspension setup for cars, Go-karts etc.

The slot through the centre allows a strip of double-sided Velcro to be passed through to hold SmartAngle to non-magnetic tubing.