Low cost motorcycle GPS for Bluetooth helmets

Posted: Wed Mar 13, 2019 4:00 pm

I am always forgetting to set up my iPhone to record rides and having a Sena bluetooth helmet set I prefer to have turn by turn directions -- even when cellular service was not available or is too pricy (O Canada!). Not wishing to pay the $$$ for a motorcycle GPS like a Garmin Zumo (I need multiples to cover all the bikes), I set out to make my own using an inexpensive car GPS.

I chose the Garmin Drive 50 with a 5" display for the GPS since I wanted a device with ample internal memory for storing multiple maps and that could take an SD card if more was needed. Cheap enough, just $70 with tax and shipping for a refurnished device with all the bits needed to mount it. The downside of a car GPS is they lack the ability to pair with a helmet communicator like the Sena SMH-10R I have been using, so to solve this I added a $20 bluetooth transmitter to take the audio from the speaker and route it to my helmet.

Parts required
Garmin Drive 50 (or similar)
Taotronix TT-BA01BT Bluetooth Transmitter
USB mini/micro dual cable
17mm ball mount
T4 driver and plastic opening tool (to split open the Garmin case)

First make sure you can pair the helmet with the TT-BA01, on the Sena I used the media channel pairing so I can have both my phone and the Garmin connected at the same time.

The Garmin is modified by removing the four T4 screws and using the case splitting tool to separate the cases. The cases are connected with a ribbon cable so open carefully and lay the cases on the workbench for the surgery.

The speaker plugs into the logic board so I removed it and used the wires and connector to attach to the stereo audio connector that comes with the TT-BA01, connecting the black lead wire to the left and right audio channels and the blue lead to the two grounds. Soldered the wires together. insulated with some shrink tubing, and after adding some cable ties to secure the wiring to the back case the assembly was complete. I clipped the wires together and tested the Bluetooth before soldering, the sound was muted so I changed them around and it worked correctly so check this if aren't using the Garmin Drive 50 as the GPS. It should look something like this with red oval showing the wiring connector *since everything is black at this point):

The back side showing the TT-BA01 and the 17mm mount, I used some command strips to attach in case I need to remove the TT-BA01 but I doubt I will.

After testing the connection the cases were snapped together and I started the waterproofing process. This I learned from gpsKeven and involves applying some silicone sealant around seam between the display and the case. To protect the screen from errant silicone, use post-it notes or painters tape to mask off the display.

Then apply the silicone and force it under the edge, watch the gpsKevin video here for all the details: https://youtu.be/s2UvIoL78Cg

Power is supplied using a goofy cable since the Garmin uses a mini USB connector and the TT-BA01 uses a micro USB. Turns out Amazon has a solution for this:

Here the final result, ready to mount on a bike:

Posted: Wed Mar 13, 2019 4:52 pm

A free alternative is to download the maps "OFFLINE" while you have coverage or wifi. Then you can use Google maps without using cellular.

Posted: Wed Mar 13, 2019 5:42 pm

Google Maps happens to be too primitive for the range of riding I might encounter, some of which might not include roads, so simple mapping products are not an option. With the dedicated GPS I can just ride and leave my phone in my pocket. The Garmin also allows me to load OSM (Open Street Maps), which provide a large number of routable maps including USGS terrain maps. I don't think Google can provide that level of detail when the terrain view is used.

Finally I don't use any Google (or Facebook) products since I don't want them to know where I happen to be. Twisted Evil

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