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Testing the Dealextreme ET411 GPS module

Started by Jan Panteltje May 11, 2012
Ordered the Dealextreme GPS module about a week?? ago,
came really fast, made a small test board:
 http://panteltje.com/pub/testing_dealextreme_E411_GPS_module_IMG_3501.png
That little pink thing with the red LED is the module.
It says RS232, but really is only 3V logic level in and out,
so I added a 7805 for its 5V supply, and a MAX232 (on the back):
 http://panteltje.com/pub/GPS_test_board_backside_with_MAX232_IMG_3502.png
In a free moment of anticipation I scribbled some software parser
for the messages it was supposed to send,
and INDEED, it works!
 http://panteltje.com/pub/GPS_module_working_IMG_3510.png

Took some time to get a first fix, probably thought it was still in China,
but now it locks in a few seconds, and that is indoors! Very good and sensitive chipset.
No need to even send commands to it, by default its sends all possible
data every seconds, your PC needs to be able to keep up though.
Its position and UTC time seem OK too.
Came very fast directly from Nanshan District Shenzhen China, had to sign for it.
Seems Dealextreme is indeed just a frontend?

Anyways I am happy with it.
The parser I wrote in C, and is just a quick hack,
needs some work, if anybody wants it I can put the source code (Linux)
on the website.
I am sure there are plenty of better programs, but hey this is more fun.

I measure about 30mA (inclusive MAX232), the MAX runs on 5V, and to match the logic
level I added a divider 2k2 / 3k3 to make the 5V signal into 3V signal.
Reverse the 3V is accepted by the MAX on 5V.
RS232 USB adaptor to laptop, there you go.

On 5/11/2012 10:54 AM, Jan Panteltje wrote:
> Ordered the Dealextreme GPS module about a week?? ago, > came really fast, made a small test board: > http://panteltje.com/pub/testing_dealextreme_E411_GPS_module_IMG_3501.png > That little pink thing with the red LED is the module. > It says RS232, but really is only 3V logic level in and out, > so I added a 7805 for its 5V supply, and a MAX232 (on the back): > http://panteltje.com/pub/GPS_test_board_backside_with_MAX232_IMG_3502.png > In a free moment of anticipation I scribbled some software parser > for the messages it was supposed to send, > and INDEED, it works! > http://panteltje.com/pub/GPS_module_working_IMG_3510.png > > Took some time to get a first fix, probably thought it was still in China, > but now it locks in a few seconds, and that is indoors! Very good and sensitive chipset. > No need to even send commands to it, by default its sends all possible > data every seconds, your PC needs to be able to keep up though. > Its position and UTC time seem OK too. > Came very fast directly from Nanshan District Shenzhen China, had to sign for it. > Seems Dealextreme is indeed just a frontend? > > Anyways I am happy with it. > The parser I wrote in C, and is just a quick hack, > needs some work, if anybody wants it I can put the source code (Linux) > on the website. > I am sure there are plenty of better programs, but hey this is more fun. > > I measure about 30mA (inclusive MAX232), the MAX runs on 5V, and to match the logic > level I added a divider 2k2 / 3k3 to make the 5V signal into 3V signal. > Reverse the 3V is accepted by the MAX on 5V. > RS232 USB adaptor to laptop, there you go. >
Nice work Jan, looks like a fun project! I'm glad you've had good luck with DealExtreme. I ordered several items from them in early January, and it took about 3 months for any of them to be shipped, and then another 2 months for some of the items to dribble in. The Chinese New Year might have been part of the problem. Several items I ordered never shipped at all, and I needed to cancel them. One of the items I ordered arrived DOA, and at first their customer service people didn't want to honor their return policy and wanted me to get it "repaired" somehow locally. Yeah, sure. They eventually allowed me to send it back to their return address in the US. Maybe I'll get a replacement in a few months, maybe not. I'm not super-upset over it; given the nature of the company I knew going in it was a case of caveat emptor and that I might be disappointed with their service. I'm pretty sure most of the items available aren't kept in any kind of stock and are either just-in-time ordered from the manufacturers or drop-shipped, so anything you buy is pretty much at the mercy of what the suppliers are up to. There are a lot of cool parts like the one you used for your project available; it's just unfortunate that, at least for me, the fulfillment aspect was so shoddy.
Jan Panteltje wrote:
> Ordered the Dealextreme GPS module about a week?? ago, > came really fast, made a small test board: > http://panteltje.com/pub/testing_dealextreme_E411_GPS_module_IMG_3501.png > That little pink thing with the red LED is the module. > It says RS232, but really is only 3V logic level in and out, > so I added a 7805 for its 5V supply, and a MAX232 (on the back): > http://panteltje.com/pub/GPS_test_board_backside_with_MAX232_IMG_3502.png > In a free moment of anticipation I scribbled some software parser > for the messages it was supposed to send, > and INDEED, it works! > http://panteltje.com/pub/GPS_module_working_IMG_3510.png > > Took some time to get a first fix, probably thought it was still in China, > but now it locks in a few seconds, and that is indoors! Very good and sensitive chipset. > No need to even send commands to it, by default its sends all possible > data every seconds, your PC needs to be able to keep up though. > Its position and UTC time seem OK too. > Came very fast directly from Nanshan District Shenzhen China, had to sign for it. > Seems Dealextreme is indeed just a frontend? > > Anyways I am happy with it. > The parser I wrote in C, and is just a quick hack, > needs some work, if anybody wants it I can put the source code (Linux) > on the website. > I am sure there are plenty of better programs, but hey this is more fun. > > I measure about 30mA (inclusive MAX232), the MAX runs on 5V, and to match the logic > level I added a divider 2k2 / 3k3 to make the 5V signal into 3V signal. > Reverse the 3V is accepted by the MAX on 5V. > RS232 USB adaptor to laptop, there you go. >
Nice! Ed
[This followup was posted to sci.electronics.design and a copy was sent 
to the cited author.]

In article <joj96k$8re$1@news.albasani.net>, pNaonStpealmtje@yahoo.com 
says...
> > It says RS232, but really is only 3V logic level in and out, > so I added a 7805 for its 5V supply, and a MAX232 (on the back): > http://panteltje.com/pub/GPS_test_board_backside_with_MAX232_IMG_3502.png > > I measure about 30mA (inclusive MAX232), the MAX runs on 5V, and to match the logic > level I added a divider 2k2 / 3k3 to make the 5V signal into 3V signal. > Reverse the 3V is accepted by the MAX on 5V. > RS232 USB adaptor to laptop, there you go.
Very nice work there getting it going. May I recommend that next time you have to interface to a "TTL serial" device like this that you pickup one of these cables... http://www.mouser.com/ProductDetail/FTDI/TTL-232R-3V3/? qs=Xb8IjHhkxj7SwwJJ1ZsBK3yD%252b8s8BiR1 I keep several on hand just because they are so darned useful and time saving. -- Michael Karas Carousel Design Solutions http://www.carousel-design.com
On Fri, 11 May 2012 22:29:34 -0700, Michael Karas
<mkaras@carousel-design.com> wrote:

>[This followup was posted to sci.electronics.design and a copy was sent >to the cited author.] > >In article <joj96k$8re$1@news.albasani.net>, pNaonStpealmtje@yahoo.com >says... >> >> It says RS232, but really is only 3V logic level in and out, >> so I added a 7805 for its 5V supply, and a MAX232 (on the back): >> http://panteltje.com/pub/GPS_test_board_backside_with_MAX232_IMG_3502.png >> >> I measure about 30mA (inclusive MAX232), the MAX runs on 5V, and to match the logic >> level I added a divider 2k2 / 3k3 to make the 5V signal into 3V signal. >> Reverse the 3V is accepted by the MAX on 5V. >> RS232 USB adaptor to laptop, there you go. > >Very nice work there getting it going. > >May I recommend that next time you have to interface to a "TTL serial" >device like this that you pickup one of these cables... > >http://www.mouser.com/ProductDetail/FTDI/TTL-232R-3V3/? >qs=Xb8IjHhkxj7SwwJJ1ZsBK3yD%252b8s8BiR1 > >I keep several on hand just because they are so darned useful and time >saving.
For those trying this at home, don't forget to configure the FTDI cable's EEPROM to invert the TXD and RXD signals. "TTL serial" will mark low, just like RS-232, but the FTDI chip defaults to talking to a UART's output, which will mark high. -- Rich Webb Norfolk, VA
On 12 Maj, 15:44, Rich Webb <bbew...@mapson.nozirev.ten> wrote:
> On Fri, 11 May 2012 22:29:34 -0700, Michael Karas > > > > > > > > > > <mka...@carousel-design.com> wrote: > >[This followup was posted to sci.electronics.design and a copy was sent > >to the cited author.] > > >In article <joj96k$8r...@news.albasani.net>, pNaonStpealm...@yahoo.com > >says... > > >> It says RS232, but really is only 3V logic level in and out, > >> so I added a 7805 for its 5V supply, and a MAX232 (on the back): > >> =A0http://panteltje.com/pub/GPS_test_board_backside_with_MAX232_IMG_35=
02...
> > >> I measure about 30mA (inclusive MAX232), the MAX runs on 5V, and to ma=
tch the logic
> >> level I added a divider 2k2 / 3k3 to make the 5V signal into 3V signal=
.
> >> Reverse the 3V is accepted by the MAX on 5V. > >> RS232 USB adaptor to laptop, there you go. > > >Very nice work there getting it going. > > >May I recommend that next time you have to interface to a "TTL serial" > >device like this that you pickup one of these cables... > > >http://www.mouser.com/ProductDetail/FTDI/TTL-232R-3V3/? > >qs=3DXb8IjHhkxj7SwwJJ1ZsBK3yD%252b8s8BiR1 > > >I keep several on hand just because they are so darned useful and time > >saving. > > For those trying this at home, don't forget to configure the FTDI > cable's EEPROM to invert the TXD and RXD signals. "TTL serial" will mark > low, just like RS-232, but the FTDI chip defaults to talking to a UART's > output, which will mark high. >
where have you seen "TTL serial" be same polarity as rs232? I've only ever seen the inversion in drivers like max232 -Lasse
I have searched high and low on the Dealextreme web site, but could not 
find the "ET411 GPS module".

Does any one have a direct link ?

Thanks
On a sunny day (Sat, 12 May 2012 09:23:24 -0600) it happened hamilton
<hamilton@nothere.com> wrote in <jolv9f$ec7$1@dont-email.me>:

> >I have searched high and low on the Dealextreme web site, but could not >find the "ET411 GPS module". > >Does any one have a direct link ? > >Thanks
The link is on the same page you referred to: http://www.dealextreme.com/p/em-411-gps-engine-board-module-with-sirf-star-iii-chipset-80037 from http://diydrones.com/profiles/blogs/cheap-gps-modules-at
On a sunny day (Fri, 11 May 2012 21:33:47 -0400) it happened ehsjr
<ehsjr@nospamverizon.net> wrote in <jokelt$e2c$1@news.eternal-september.org>:

>Jan Panteltje wrote: >> Ordered the Dealextreme GPS module about a week?? ago, >> came really fast, made a small test board: >> http://panteltje.com/pub/testing_dealextreme_E411_GPS_module_IMG_3501.png >> That little pink thing with the red LED is the module. >> It says RS232, but really is only 3V logic level in and out, >> so I added a 7805 for its 5V supply, and a MAX232 (on the back): >> http://panteltje.com/pub/GPS_test_board_backside_with_MAX232_IMG_3502.png >> In a free moment of anticipation I scribbled some software parser >> for the messages it was supposed to send, >> and INDEED, it works! >> http://panteltje.com/pub/GPS_module_working_IMG_3510.png >> >> Took some time to get a first fix, probably thought it was still in China, >> but now it locks in a few seconds, and that is indoors! Very good and sensitive chipset. >> No need to even send commands to it, by default its sends all possible >> data every seconds, your PC needs to be able to keep up though. >> Its position and UTC time seem OK too. >> Came very fast directly from Nanshan District Shenzhen China, had to sign for it. >> Seems Dealextreme is indeed just a frontend? >> >> Anyways I am happy with it. >> The parser I wrote in C, and is just a quick hack, >> needs some work, if anybody wants it I can put the source code (Linux) >> on the website. >> I am sure there are plenty of better programs, but hey this is more fun. >> >> I measure about 30mA (inclusive MAX232), the MAX runs on 5V, and to match the logic >> level I added a divider 2k2 / 3k3 to make the 5V signal into 3V signal. >> Reverse the 3V is accepted by the MAX on 5V. >> RS232 USB adaptor to laptop, there you go. >> > >Nice! > >Ed
Thanks!
On a sunny day (Fri, 11 May 2012 22:29:34 -0700) it happened Michael Karas
<mkaras@carousel-design.com> wrote in
<MPG.2a17951cfe4ffbe59896d7@news.eternal-september.org>:

>[This followup was posted to sci.electronics.design and a copy was sent >to the cited author.] > >In article <joj96k$8re$1@news.albasani.net>, pNaonStpealmtje@yahoo.com >says... >> >> It says RS232, but really is only 3V logic level in and out, >> so I added a 7805 for its 5V supply, and a MAX232 (on the back): >> http://panteltje.com/pub/GPS_test_board_backside_with_MAX232_IMG_3502.png >> >> I measure about 30mA (inclusive MAX232), the MAX runs on 5V, and to match the logic >> level I added a divider 2k2 / 3k3 to make the 5V signal into 3V signal. >> Reverse the 3V is accepted by the MAX on 5V. >> RS232 USB adaptor to laptop, there you go. > >Very nice work there getting it going. > >May I recommend that next time you have to interface to a "TTL serial" >device like this that you pickup one of these cables... > >http://www.mouser.com/ProductDetail/FTDI/TTL-232R-3V3/?qs=Xb8IjHhkxj7SwwJJ1ZsBK3yD%252b8s8BiR1 > >I keep several on hand just because they are so darned useful and time >saving.
That is a nice solution, but at 16Euro59 (about 21$) it is more expensive than my module, and that is ex shipping!