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Using Reyax GPS sensor

Posted: Sun Apr 07, 2019 9:36 am
by Engenia
I've connected a HC-06 bluetooth to serial bridge to a Reyax RY8253F to create a cheap and cheerful 10Hz GPS sensor. The RY8253F arrived as a RY825CF, which is an RS232 to BT bridge with Flash memory, but I removed the RS232 driver chip and linked the 3.3V serial Rx & Tx lines direct, to be compatible with the HC-06.
The phone is a Samsung Galaxy Note II, GT N7105 running Android 4.4.2. It successfully paired with the HC06.
I then used a previously downloaded app, "10Hz", to change the GPS read rate to 10 Hz. This took a couple of tries but it was ultimately successful. A subsequent try showed that the rate was already set to 10 Hz.

I then downloaded "Bluetooth GPS" by GG MobLab from the AppStore and it successfully read the Reyax sensor and updated as I moved about the back yard. I also left the sensor in a fixed position and moved about again to prove that the fix wasn't coming from the phone sensor.

I then started HLT and added the HC-06 to the sensor list. It came up "Disabled".
Clicking on it came up with the suggestion to select Refresh, which I did, but to no avail.

What else must I do to enable the HC-06/Reyax GPS sensor?

Re: Using Reyax GPS sensor

Posted: Sun Apr 07, 2019 11:37 am
by Harry
Which connection type is used to connect smartphone and your accessory? BT SPP or BT LE?

- Harry

Re: Using Reyax GPS sensor

Posted: Sun Apr 07, 2019 2:13 pm
by Engenia
Pretty sure the HC-06 is not BT-LE. It's been around for a very long time.
https://core-electronics.com.au/bluetoo ... hc-06.html
It can be picked up on ebay for a dollar.

Re: Using Reyax GPS sensor

Posted: Sun Apr 07, 2019 2:40 pm
by Harry
O.k. There are several potential reasons a sensor entry is going to "Disabled" for BT SPP accessories:

1) A specific sensor filter has been set in LapTimer's Expert Settings (Settings ‣ Expert Settings ‣ Accessory Tweaks ‣ Use Sensors Containing Name).
2) The search for the sensor has gone on too long (need to check, but several minutes). LapTimer will disable sensor discovery after some time to save battery. Send LapTimer to background and pull it forward again. This will restart sensor discovery.
3) You have another BT sensor connected already and you are driving. Stop and wait for the sensor to connect before driving again.

Some smartphones have problems connecting to older BT devices. You can try "Force Insecure BT Connection" in Expert Settings to work around this issue.

- Harry

Re: Using Reyax GPS sensor

Posted: Sun Apr 07, 2019 2:51 pm
by Engenia
The completed BT GPS sensor:-
Image
The sensor measures 6 x 4 x 2.5 cm and cost under AUD30 in parts
Image
Left to right: 12V - 5V supply (my design shown, but they are on ebay for a couple of dollars); Reyax GPS sensor (RY825CF with the RS232 buffer removed) $21 on ebay; BT to 3.3V serial bridge (HC-06 - a couple of dollars on ebay)

Re: Using Reyax GPS sensor

Posted: Sun Apr 07, 2019 3:05 pm
by Engenia
Harry wrote: Sun Apr 07, 2019 2:40 pm1) A specific sensor filter has been set in LapTimer's Expert Settings (Settings ‣ Expert Settings ‣ Accessory Tweaks ‣ Use Sensors Containing Name).
I set this to "HC-06" to make sure that this BT device was the only one that HLT connected to.
2) The search for the sensor has gone on too long (need to check, but several minutes). LapTimer will disable sensor discovery after some time to save battery. Send LapTimer to background and pull it forward again. This will restart sensor discovery.
HLT had only been running for less than a minute. It comes up immediately as "disabled"
3) You have another BT sensor connected already and you are driving. Stop and wait for the sensor to connect before driving again.
I tested this in the front yard. I've only paired this phone to one BT device, the HC-06
Some smartphones have problems connecting to older BT devices. You can try "Force Insecure BT Connection" in Expert Settings to work around this issue.
I had set it to force insecure BT connection, just in case.

(Heading to bed now. It's after midnight here)

Re: Using Reyax GPS sensor

Posted: Sun Apr 07, 2019 3:07 pm
by Harry
Remove the filter please.

Harry

Re: Using Reyax GPS sensor

Posted: Sun Apr 07, 2019 11:27 pm
by Engenia
Removing "HC-06" from the filter list solved the problem. It's running at 10Hz.
Thanks Harry.

Now to permanently attach it to the bike and head for Wakefield Park :D