Version 1.1 is here !

A project log for GNSS bluetooth module with u-blox NEO8N

Here I build a external GNSS module for mobile devices without or unsatisfactory navigation GNSS option.

dechemistdechemist 08/04/2020 at 19:460 Comments


- Over 27.5 h continous run time with one 18650 (tested while hiking)
- USB-port for u-center programming and as USB-GPS device
- GPS, Glonass and Galileo configured
- relative small form factor
- Typical error between the tracks of the way to a destination and back 2-3 m (hills / mountains, forrest)
- On/Off switch !
- Dimensions: 8.8 x 8.8 x 5.4 cm
- Propper 7 x 7 cm groundplate as recommanded by the antenna manufacturer (MOLEX)

Changes from v1.0 to 1.1
- Mini USB-port for programming via u-center (also works in linux with wine without further configuration)
- Only one 18650 battery is needed (LP3981 LDO voltage regulator for battery applications)
- No debug serial connections anymore
- Better (but still wooden) case
- Added an charging option for rechargeable coin cells
- PCB groundplate

I mainly used the module for tracking my hikes. So I ased my girlfriend to sew me a holding strap to put it on the backpack (Thanks !).

The GNSS-module also works fine while driving in a car for < 100 km/h. Above that it looses the GPS signal. I assume this is because I set the navigation setting to 'pedestrian' and not 'automotive'. Unfortunally right now I have no chance to test it with the automotive setting.

All in all I am very pleased with the project. The u-blox M8N chip preformes extraordinary well in my opinion.

Here are some pictures from the new module. The case is again lasercut from 4. 5 mm plywood. On one side we have a on/off switch and a power and GPS-fix LED.

The antenna is held on the groundplate (PCB with copperlayer) with double sided tape and is exactly centered. The USB interface for know is only accessible by opening the case. I may change that in a upcomming version. Except for that, nothing has changed mutch from the first version 1.0. The PCB has the same dimentions and fits nicely on top of the groundplate. To hold the PCBs in place I used typical standoffs for PCBs so that the case can be opend with only three screws.

In over 27 h I only had one malfunction where my mobile phone lost the bluetooth signal while hiking and therefore could not record my position. I am not sure whether it was the phone's fault or the HC-06 module's. Nevertheless I am very pleased with this statistic for a hobbiest project (Not to mention that is also could happen with a commercial device). I was a steap learning curve for me, and shurely a lot of fun testing and playing around with my module.