$39.99 GPS for UAV's

[Medve]

Hey All,
was over at Fry's electronics last night. They are having a sale on the Geco 101, factory reconditioned, for $39.99. This is one of the smallest and lightest GPS's I've found, and can be made more so if you take off the plastic housing, and make the LCD screen removable with a plug in jack.
Just thought I'd let you all know.
Medve

[radiohound]

Interesting. I thought the 101 did not have a serial port? You can access the pins and they are active for nmea out?

[Medve]

Sorry, I was going off what I saw on my 301. not sure if you can access them inside. hoping someone who has one can check. I just saw them on sale, so thought I'd mention it.

[Mr.RC-CAM]

That would be very handy if there was a serial port buried inside. We need to find a hacker that is willing to open up the 101.

Edit: Google came up with this hack for the eXplorist GPS: http://rhamphorinkx.newmail.ru/connect.htm

[joelhaasnoot]

I'm pretty sure that device has no serial port. The Geco 101 unit is meant as a 'hiking' unit with no PC access. The Weblink mentioned, is for eXplorists units, which are not the same it looks like as the Geco.

[Mr.RC-CAM]

I would like to try a serial port hack on the Geko 101. Does anyone have one in good condition that they wish to sell? Or, I could trade a new Vizion OSD Board (http://www.rcgroups.com/forums/showthread.php?t=494379) for one.

I'm looking for a good deal (read: cheap) so that I don't waste too much on a failed attempt to hack the little fellow. Please PM me if you can help out.

[pilotandy]

Before you guys go hacking handheld gps units apart, take a look at this:

http://www.futurlec.com/GPS.shtml

http://www.crownhill.co.uk/product.php?prod=1474

The second link has a nice interface diagram. This unit will use far less power than a hacked apart handheld unit, and it will most likely weigh less and take up less space.

[kd7ost]

Cool,

Thanks for the info pilotandy,

Some of the devices we are using to guide a plane using a GPS unit require that the GPS do the navigating. Items like the RCAP connect up to a GPS following a "route" or "goto". The GPS is being the waypoint management device. This is why there is interest in handheld navigation type GPS units.

Dan

[pilotandy]

It looks like you guys have got some awesome stuff going here. I can't wait to read through this forum and check out all of the pictures. I just made a post about a project I'm working on.

The GPS module I linked above is approximately 26mm x 26mm x 3mm. So about an inch square and an eighth of an inch thick. It requires very few components to hook up power and the backup battery. It outputs standard serial NMEA signals, just like many handheld units.

The downside to using the board from a handheld unit is all of the extra components used to process and display the gps data, as well as any other functions the unit provides. Not only will these add weight, but they also drain more power.

With a 6' UAV airplane the weight/powerdrain might be negligible. With smaller craft it could be more of a burden.

Edit:

I just checkat out the RCAP site. I guess RCAP requires selectable waypoints. You'd probably have to modify the RCAP firmware to get something like this to work :mad:

Edit again:

After reading the RCAP website over a few times I completely understand what you're saying Dan. I didn't realize the system relied so heavily on the GPS unit for navigation. I plan incorporating the navigation math into the firmware for the project I'm working on.

[Mr.RC-CAM]

I have used several OEM GPS modules. None that I have come across have waypoint engines in them.

Adding waypoint navigation to the host microcontroller would not be trivial. Especially the user interface. So, for now, I am interested in working on my more immediate needs. Anyways, anyone have a 101 they need to unload?

[ALtitudeap]

subscribe

[Mr.RC-CAM]

Update: I have yet to find a cheap enough Geko 101 on eBay (going rate is $55-$70 shipped). FWIW, I'm still interested in trading a Vizion OSD for one. But, as a last resort, I'll try Fry's tomorrow night (would be sweet to find one of those $39.99 deals). After that, I'll just forgot my urge to hack and simply stick with the 201. :(

[Medve]

RC-CAM, you can't forget your urge to hack. It what we live for. the smell of flux, solder, melting plastic, skin.....ouch, he he. I have the Geco 301, and got it because it had the barometric altimeter built in. Hence the altitude it would report down to the ground station would be much more accurate. But I think the 101 should be hackable. Now if you could just figure out a way to have the GPS trigger one of your camera firing circuits when it's over a specific way point, that would be way cool.

[Mr.RC-CAM]

I made the 60 mile round trip and visited Fry's (I would have just called, but for those that know Fry's ...). They had a half dozen of the refurbished 101's in a locked display case, but they were marked at $59.95.

Funny thing, I had them look up the Geko 201's price. Their inventory system reported that they had been closed out some time ago at $29.95. Now that would have been a very sweet deal indeed.

The hunt for a cheap hackable 101 is over. I'm calling uncle and will just interface with a 201 instead. The hack would have been interesting to try since I don't believe the 101 has the smart routing feature.

[Mr.RC-CAM]

Over the weekend Fry's had the refurbished 101's on sale for $39.95 again. Looks like I visited them a couple days too early.

[kd7ost]

The hunt for a cheap hackable 101 is over. I'm calling uncle and will just interface with a 201 instead. The hack would have been interesting to try since I don't believe the 101 has the smart routing feature.

This sounds interesting. I didn't catch it when you first posted it. What makes you think the 101 doesn't have smart route finding if I may ask? That would be cool.

Dan

[lvspark]

Subscribe.

I hate the smart routing! Hate, Hate, HATE!!!!!

[Mr.RC-CAM]

What makes you think the 101 doesn't have smart route finding if I may ask? It's a hunch. The 101 has many features that are crippled, including the waypoint engine. The bad thing is that the receiver does not support WAAS.

The 101 vs 201 feature summary:

[radiohound]

Over the weekend Fry's had the refurbished 101's on sale for $39.95 again. Looks like I visited them a couple days too early.

My ebay Geko 101 gets here on Friday, then it will be headed your way. :) Let us know what you discover, and thanks for the trade.

Walter

[Mr.RC-CAM]

Let us know what you discover, and thanks for the trade.I'll admit it is a huge leap of faith that I can tap the NMEA sentence data, especially at a point that includes the tracking fields. Worse case is that I end up with a fancy paper weight. But, that is the nature of hacking.

Please contact me when the 101 arrives so that we can arrange for the Vizion board trade.

[kd7ost]

I'm hanging on this thread too. Lret me know if you need me to trace back the chassis plug wires to the source in a 201.

Dan

[Mr.RC-CAM]

Thanks for the offer. I actually have a Geko 201, which may be of some use in the reverse engineering of the 101. But, if things go badly, I may have two fancy paper weights.

[Mr.RC-CAM]

The 101 arrived today. I am sorry to report that despite the hardware essentially being a 201, the Garmin folks do not send the NMEA sentences to the internal RS-232 factory test header. It does seem like it could be reflashed as a 201 using the loader code from the Garmin site. I'll skip that.

Over the last couple of weeks I've observed some quirky things with the NMEA sentences on the Geko 201. (1) I've seen that heading/course data values have a min of 0 and a max of 360. How is that possible? (2) The $GPRMB steering data field sometimes does not point in the direction that is the most efficient. Once in a blue moon it suggests a direction that would require >180 turn. Very weird. (3) I hate the smart routing. Unless I am careful, it really dorks up my tests!

[Medve]

Mr. RC, does the 301 suffer from the same issues? I've not had a chance to mess with mine. Other than the Garmins, what options do we have for good, small, gps's?

[Mr.RC-CAM]

The issues I have seen are not serious problems. Just observations. Value wise, the Geko is a nice little package.