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Arduino gps speedometer


New Member
Hello, I would like to build a battery powered arduino gps speedometer.

In this arduino based project I would like to include a few features.

-I would like it to turn on some lights when It detects that the speed is going down (if the speedometer is going at 10km per hour and slowing down I want it to turn on two led panels)

-I also would like it to consume as minimum power as possible while still lighting up the led panels at least at 80%

-And finally I want it to always have some led panels always turned on while the arduino is getting power

If you think you can help me please contacts me via my email : [email protected]

Further details such as the power needed for the led panels will be sent via email to you.


Well-Known Member
Most Helpful Member
GPS Module with Ceramic Antenna for DIY Handheld Positioning System for $7.86


This is the data, info & an Arduino sketch that works out of the box.


UNO R3 ATmega328P Development Board With Boot Loader For Arduino UNO $6.67

Just 3 pins / wires to solder.

This is the NEMA ascii sentence that it works with


225446 Time of fix 22:54:46 UTC

A Navigation receiver warning A = OK, V = warning

4916.45,N Latitude 49 deg. 16.45 min North

12311.12,W Longitude 123 deg. 11.12 min West

000.5 Speed over ground, Knots

054.7 Course Made Good, True

191194 Date of fix 19 November 1994

020.3,E Magnetic variation 20.3 deg East

*68 mandatory checksum

The speed variable in knots is lndSpeed.
It is an ascii string but you can make it an integer with this instruction: int value = my_string.toInt();

You can convert with 1 knot = 1.151 or 62 MPH = 54 knots & 42 MPH = 36.5 knots.

You can tweak the program to do what you want


New Member
Hello, I would like to build a battery powered arduino gps speedometer.
I doubt if arduino can pull this off. Measuring speed with GPS data itself is a complex task I have seen how the android applications does this and they either use differential or doppler dhift technique but even then they are accurate only to an extent. Some applications also make use of the gyroscope and accel data along with GPS data to do this.

I have worked with GPS modules previously with arduino and their update interval is very bad. It is hard to calculate speed in such a set-up i believe.


Well-Known Member
Most Helpful Member
I doubt if arduino can pull this off. Measuring speed with GPS data itself is a complex task
The Arduino doesn't have to do this. The speed is in the NEMA sentence and all the Arduino has to do is read the sentence.



New Member
Ohh yes you are correct, I remember using a NEO-6M GPS module with speed data being thrown out through serial ready to be phrased. Thanks mike for correcting me, I happened to forget that . would someday try to build something with it


New Member
Many thanks to all for above info. Me & team are trying to develop a product / prototype where Family / Employer can be alerted if a vehicle goes beyond a threshold which can be set by the Family / Employer. Mobile app & Web App too for driving history also...A battery powered Ardunio * GPS connected to ThingWorx (PTC) is the top level approach...Wish me Luck!

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