The Eggfinder - A Low-Cost GPS/RF Tracking System

[matthew]

LOL...

I have not had a chance to get my hands around the Australian regulations yet, other than to find out that they are similar to Canada but with some tighter frequency allocations because you have cell phones on the lower 900 MHz band up to 915 MHz. Assuming that there are no import issues, I will providing them on frequencies that are in compliance with Australian regulations, but it will probably be at least a month.

I can wait a month. Add another to your batch count, please.

 

[Zeroignite]

So, from the sounds of it the GPS module will just be spitting out NMEA, not arbitrary telemetry? I was kinda hoping it could hook up to an Eggtimer so you could get realtime notifications of events and apogee altitude.

 

[cerving]

Well, it's a tracker, not a telemetry device. There is one important difference: You need to have your telemetry connection stay solid all the way through the flight, whereas with a tracker it's OK to lose it at boost (or even high altitudes) as long as you can pick it up somewhere on the way down, close to your landing spot. I think Derek has the right idea about using the 250 mW XBee module for telemetry purposes, it's very robust... and a lot more expensive.

I do like the idea about having the Eggtimer's telemetry routine give you event notifications, right now it only gives you elapsed time from liftoff and altitude. I'll add that to my list for the next build... it's gonna be awhile, I've been way too busy with the Eggfinder. Maybe I'll throw together a board set based on the 250 mW Xbee's so you can interface them to an Eggtimer, but quite frankly it would probably not be terribly cost-effective; the Xbee Pro900HP's are about $40 each.

So, from the sounds of it the GPS module will just be spitting out NMEA, not arbitrary telemetry? I was kinda hoping it could hook up to an Eggtimer so you could get realtime notifications of events and apogee altitude.

 

[Derek]

Yeah, the price is the downside to the digi radios and the primary reason my tracker costs as much as it does.

I keep toying with the idea to make an arduino based, license free altus metrum like clone. My idea is to make an add on board for an arduino pro micro (or teensy, can't decide) that has a baro, gps, xbee socket, 3 axis accel and maybe a gyro and compass. I actually have all the parts to try this out but I have't gotten off my butt to write the code. I know the accel on the board I have won't handle rockets very well, but it is a start.

One of these days...

 

[Pyropetepete]

Send me one to the UK! Need it
For my L1 & L2 build I'm doing on here.


Sent from my iPhone using Rocketry Forum

 

[cerving]

I'd love to, but 900 mHz isn't an unlicensed band in the UK/EU. They use 433 MHz and/or 868 MHz. Also, I need to get educated on what I need to do to be able to sell these internationally, it's not as easy as you might think it would be. So, for now I'm confining my sales to the US.

Send me one to the UK! Need it
For my L1 & L2 build I'm doing on here.


Sent from my iPhone using Rocketry Forum

 

[BLKKROW]

Any time frame for a different frequency? I know a lot of people around my area will be using this product and I would by one right now but I am waiting for a different frequency.

Or will you take a pre-order for one?

 

[chris m]

Cris heads up when the guy from the Midwest order there's ( IN,IL,WI ) we all fly at lest two big launches together .

 

[cerving]

Understood. If there's a delay getting out Eggfinders on frequencies other than 915 MHz, it won't be more than a few days tops. If you're in the queue already and given me a frequency request, you're not gonna lose your place in line.

BTW, my PCB vendor says I should have the boards on Monday (March 10). That's really the only hangup at this point...

 

[Pyropetepete]

I'd love to, but 900 mHz isn't an unlicensed band in the UK/EU. They use 433 MHz and/or 868 MHz. Also, I need to get educated on what I need to do to be able to sell these internationally, it's not as easy as you might think it would be. So, for now I'm confining my sales to the US.

868 MHz is the safest one to use, less people on it.

 

[Derek]

868 MHz is the safest one to use, less people on it.

Except you can't use that frequency in the us.

 

[cerving]

And not necessarily the entire EU as well. It's not yet a "harmonized" frequency like 433 MHz...

This is why I'm not ready to ship internationally yet, although theoretically I could. The EU has some very open regulations regarding the license-free bands, you can self-certify and not go through the rigamorole and expense that you have to for the US and Canada. You don't even need to submit anything, you just mark it CE and have the documentation handy in case somebody complains and they want it. The chance of that happening with a rocketry tracker is probably less than zero...

Except you can't use that frequency in the us.

 

[cerving]

For those of you who have pending orders on hold, I got the PC boards today (way ahead of schedule!) I'm waiting on the USB-serial cables but they should be here tomorrow or Monday. I'll put a set together tonight to make sure it's OK, and you'll start seeing PayPal invoices tomorrow or Saturday.

 

[Wayco]

Got my Paypal invoice and paid it this morning. Warming up my soldering skills today by starting the second Eggtimer. Bring it on Cris!

 

[cavecentral]

Holding off for now. Many projects in the works. I'll lose the parts by the time I get to releasing the magic smoke.

 

[Area66]

Paid for 2

 

[chuck5395]

Paid for 2

I thought that these were only for use in the United States.

 

[Derek]

I thought that these were only for use in the United States.

902 - 928 mhz is unlicensed in itu region 2 (the americas, greenland and some pacific islands)

https://en.wikipedia.org/wiki/ITU_region

 

[chuck5395]

902 - 928 mhz is unlicensed in itu region 2 (the americas, greenland and some pacific islands)

https://en.wikipedia.org/wiki/ITU_region

Quoting from the Eggfinder assembly guide:
"The Eggfinder uses RF modules in the 902-928 MHz IS M band manufactured by Hope RF, model HM-TRP-915. They are intended to be used only in the United States. These modules have been tested by Hope RF to be compliant with the FCC Part 15 regulations for non-licensed intentional emitters, and as such have been permitted to be imported into the US. "

 

[cerving]

Right now I only have regulatory clearance for the US. I spent some time conversing with Industrie Canada, and what came out of that was that I can sell the kit without the RF modules there but the end-user has to obtain the "component part" RF modules themselves. That's what I'm doing for Canada, and Canada only at this point. I would prefer to sell the kit complete so the end user doesn't have to go chasing around looking for parts, but the Canadian customers that I've spoken with are OK with it.

Australia and New Zealand also use pieces of the 900 MHz band, but not the entire 902-928 MHz because they have cell phones that go up to 915 MHz. New Zealand only allows 918 MHz-926 MHz. Any units I sell down under would have to be reprogrammed for their frequencies.

Interestingly enough, it looks like the UK/EU is not going to be a problem, I'll just have to switch to the 868 MHz version of the Hope RF modules. Hope RF has provided the proper ETSI testing data, and you can self-certify and mark the devices CE as long as you have the proper backup documentation in case they ask for it.

 

[Area66]

I ordered the RF module yesterday, and also the instructions, with the HM-TRP Config GUI , it seems you can adjust the frequencies

 

[cerving]

You can program the frequencies on them, of course, Hope RF has a Windows GUI utility to do it. You need to feed it 3.3v and use a serial-TTL (3.3v) interface of some sort, so you're going to have to futz around with it. Unless you really need to do it, I'd just leave it at 915 MHz for now.

I ordered the RF module yesterday, and also the instructions, with the HM-TRP Config GUI , it seems you can adjust the frequencies

 

[Area66]

You can program the frequencies on them, of course, Hope RF has a Windows GUI utility to do it. You need to feed it 3.3v and use a serial-TTL (3.3v) interface of some sort, so you're going to have to futz around with it. Unless you really need to do it, I'd just leave it at 915 MHz for now.

Since I will have 2 of them I'm gone leave default the first one and see if I need to change the second one, I don't plan to launch 2 rockets at same time.

 

[chris m]

Everyone that has ordered one of the egg finders will be very happy with them . Both units is very small . I was going to run one today but still sick in bed . And didn't feel like looking for a rocket on a big J and have it land a mile or so away even with a dual deployment set . So will have to wait till thunder struck in a few weeks

 

[ksaves2]

I really think the E.F. is a cost effective way to go for a newcomer. I still like my Beeline GPS units and like getting the KML file out to Google Earth. Now folks, if you have a USB GPS receiver, you can plug it into your laptop and futz around with MapSphere in advance, learn the software and download the maps and aerial photos you want to store on your drive. You then
will be ready to go out in the middle of no where to track. When you get the EggFinder receiver built, just plug it in and you're ready to go. Kurt

 

[jus_rockets]

I just finished putting together the Bluetooth box. It works great and now all I need in my hands is my Android phone. Cris will be doing a write up soon and it will be posted on his website.

 

[troj]

Kit received today; time to fire up the soldering iron!

Cris, I don't know what kind of magic pixie dust you sprinkle on your boxes, but you are able to get me shipments from California faster than anyone I've ever bought from!

-Kevin

 

[michigander]

Got my Kit today


really looks like fun thanks

 

[conman13]

don't forget to post some pictures after you are done with it.

 

[Wayco]

Got my tracking data today, priority mail should get it here Wednesday or Thursday. I might get it built and ready for the launch at the end of the month.
Hey Juan, I want to build a bluetooth adapter also. Link it to my Iphone. Let's get together and compare notes.