Hi All,

While waiting for my EM-406A to drain it's batteries. (Seems that it's on binary mode...)

Already done with the Xbee connections. I managed to get a remote serial connection via the wireless link so... that's okay...

I was playing around with the ArduPilot board, and looking at the different features and functions.

Was wondering... is the attached 'screenshot' of my serial dump normal? Especially the line after "next_WP:#0" and I get a "no GPS, last 10s" in between the "+++ASP:0,THH:0,RLL:60,PCH:0,***
" lines, even on the debug/simulator mode...

As I have a EM-406A... once my GPS is thawed out... would I set it to NMEA (0) or SIRF (1)? And what's the cause of the EM-406A mysteriously going into 'binary mode'?

Many thanks in advance.


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You want the 406 in Binary mode. It's much more efficient that way and easier to parse. In fact we only parse Sirf Binary for the 406.
The output looks normal to me. Can you try the 406 tester file on your Ardupilot? It should get lock and output lat and long *10,000,000 (You can't print floats from Arduino, only integers, so we leave off the ".")
Hi Jason,

Thanks for the quick reply. Well... I'm not really sure on which mode I should be running this. I just got all the parts in fairly recently.

Once I upload the ArduPilot code to the board. It was all good. I get good results like in the screenshot. Then I attached the 406 on the board. Then powered up the board. And there's no light on the 406's LED. Chris was mentioning that the GPS was on 'binary mode' (dim red LED). I spent time looking at the different suggestions from the forum... from tapping the FTDI board to the GPS to trying out Ken's "Putting your EM-406 GPS back in to NMEA mode without waiting." trick. Which when trying to unlock it showed that the GPS is still alive (faint red LED flashes) when receiving data (tried all the baud rates). Seems the sure fire solution is to keep it in storage for 10 days... til' the battery runs out.

Oh, yes I did try the 406 test file. And put it out on the patio for a couple of minutes, but only got a rapidly flashing blue (GPS) light. And I was also getting the "no GPS, last 10s" error too.

Too bad, I've got everything ready... all I need is to get the GPS working.

Hi All,

Now that the Easter festivities are done. I opened up my ArduPilot kit. And wired everything up together.

I have the blue shield board. And an EM 406 GPS.

Now... I left my ArduPilot rig (uploaded with the EM406_Tester file... and it's on the roof and linking up with it via the 900 datalink. And watching the progress via PuTTY

I am currently waiting for my GPS to get a lock. And getting a "no GPS, last 10s" for the last 5 minutes. Will leave the rig for a couple of more minutes to see if I get a good enough lock.

I don't know if my GPS is whacked or something. When I power up the board, there's a few seconds that the LED light on the GPS flash... so that must mean that the GPS is drawing power...

Really stumped... :(

You've got the config file set to SiRF, yes?

Just to repeat the obvious: If you don't read and follow the manual to the letter, you won't get this working.
Yup... did the HOWTO to the letter. As you can see from the screeshot. It's set on EM-406/SiRF.

Also getting output from the "Raw GPS Tester", I'm only getting a 'Begin GPS Test' message.

Everything else checks out... Xbee, airspeed sensors, thermopiles... just this darn GPS.
Excellent. RTFM is my usual answer, but glad that's not the case here ;-)

Okay, let's focus on the EM406. When it's on, can you see the red LED on the module is on, but super dim? (You need to cup your hands around it to see the tiny glow). If so, that means it's in binary mode.

We haven't use the EM406 for a while, but I don't remember the red LED on the module ever coming on after it's in binary mode, not even for a flash while it's booting. That suggests a problem to me. Can you check the pins in the connectors, too? They can sometimes get bent.

If you look at the string in raw format from the test app you will see this bit change from 0 to 1.
It's easy to see since it's at the beginning of the string
No Lock = A0,A2,0,5B,29,0,0, ....
Lock = A0,A2,0,5B,29,0,1, ....

You can see what the values mean here
No   YES
A0     A0      Start Sequence
A2 A2 Start Sequence cont.
0 0 Payload Length
5B 5B Payload Length cont.
29 29 Message ID
0 0 Nav Valid
0 1 Nav Valid cont.
Yeah, I usually do the RTFM bit on our old campus IRC *NIX channel. :)

Well... I'm in front of the PC now, with the ArduPilot relatively complete... everything from thermopiles, TX/RX and the Sparkfun FTDI adapter attached. And a fresh upload of the 2.5.04 firmware...


home: 0 0 0
prev_WP: 0 0 0
next_WP:#0 0 0 0
Startup: Ground
prev_WP: 0 0 0
next_WP:#1 145487760 1210521320 6100

Ready to FLY.


Powering up the ArduPilot... once the battery is connected... the red light on the main board switches on... then the GPS LED light faintly blinks and then off... after that the GPS blue LED blinks constantly...

And yes, the GPS led is sort of on very faint... at times flashing a little brighter randomly... I've checked the connectors too, and used different GPS wires.

Same setup as in my previous posts... I even had this rig out in the roof for 15-20 minutes and I never had a solid GPS lock. I might have to put it out longer... I dunno... and I'll try now.. at least it's not 35C/95F outside... (as it's the evening in my part of the world...)

Nope. I don't get HEX values on the raw GPS tester... all I get is a 'Begin GPS Test' and then nothing else. This is on 57600 baud.

On the EM406 tester. I'm getting "no GPS, last 10s".

I left the ArduPilot rig outside to try and get a GPS lock (quite dark outside). And I do indeed see a faint rapid blink GPS LED, a little faster in tempo than the GPS blue light...
I give up. I think I have a lemon here... *sigh*. Left out the ArduPilot rig out under the sky for 45 minutes hoping for a lock. No response from any of the test suite apps. And the GPS isn't even warm...

At least I know the autopilot and shield is working perfectly. And the X-Bee telemetry is happily TX/RX'ing.
That GPS does sound funky. Can you afford to replace it with a uBlox? You'll be a lot happier ;-)
Hey Chris, hope so... ;)

But yeah, all in all... the ArduPilot with the blue shield, including the X-bee adapter from Adafruit works well... Great documentation... followed every step. And it came together well...


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