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Tips and questions relating to the GPS modules from SFE
By NleahciM
#8981
Now to start my 3rd topic on this module... Hopefully my last, but that's doubtful.

I am trying to figure out the power supply for this little bugger. The manual calls for 4.5-6.5VDC, but does not elaborate any more on power supply requirements. On my board I have a very noisy 6V supply. It has 18 motors connected to it that are constantly pulsing on and off. Is this suitable?

I thought about the possibility of running the 6V through something like a 5V LDO and then filtering the 5V signal. Would that be an improvement, or will the EM-406 module care about the noisy supply line?

Thanks!
User avatar
By sparky
#9272
Hi,

My two cents : GPS receivers need as clean a power supply as you can give them. Motors flipping direction can put so really nasty power spikes on the power system. I'd recommend isolation the logic from the drive train if possible.

-Nathan
By Guest
#9290
HI,

Can I ask how to collect the data from the EM-406, or just give power and the dta will automatically output. Can I connect it with RS232 or I need to convert it. Please advise
By brianhomer
#9291
Dear sparky,

I am starting use the recent ordered EM-406, However, I need some example to connect it and get the data. where can I get this from?
I assumed use the MAX232 IC to convert the TTL to RS232 level, am I correct. then I can use RS232 collect the data. any important points I ignored?

Please comment! thank you!

Brian ho
By NleahciM
#9297
sparky wrote:Hi,

My two cents : GPS receivers need as clean a power supply as you can give them. Motors flipping direction can put so really nasty power spikes on the power system. I'd recommend isolation the logic from the drive train if possible.

-Nathan
Hi Nathan - I ended up using a 1mh super low resistance inductor in series with the +6V line as well as two ultra low resistance caps, a 10uf tantalum and a .1uf ceramic, going from EM-406 supply to EM-406 ground. I got a message back from tech support at usglobalsat where they said:

"No problems are found if you utilized a 6V line within 100mV noise. If noise exceeds 100mV, it may affect EM406 performance. Adding a bypass capacitor and using 5V LDO on the 6V line are both feasible. An alternative to this, is adding a bead on the 6V line."

so I think my solution should be more than adequate.
Anonymous wrote:HI,

Can I ask how to collect the data from the EM-406, or just give power and the dta will automatically output. Can I connect it with RS232 or I need to convert it. Please advise
Give it power and it will start spitting out NMEA 0183 data over the uart. this is all outlined in the datasheet, which you have obviously not read.
brianhomer wrote:Dear sparky,

I am starting use the recent ordered EM-406, However, I need some example to connect it and get the data. where can I get this from?
I assumed use the MAX232 IC to convert the TTL to RS232 level, am I correct. then I can use RS232 collect the data. any important points I ignored?

Please comment! thank you!

Brian ho
A max232 circuit is indeed all you need to connect the EM-406 to a RS-232 line.
By brianhohk
#9307
Understood and much appreciated!
By mericas
#9313
I was hoping I could power the GPS directly from a battery since all the other components on the board were 3.3V. I tried using 4 AA batteries and it worked, sort of. Not very reliable. I finally added a 5V LDO for the GPS and now it is very happy.

Now I want to redesign my board with a 5V LDO feeding the GPS and the 3.3V LDO (instead of both LDO's running off the supply voltage). I was thinking about switching regulators but LDOs are so easy, and cheap.
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