what would YOU pay for a NEW tiny Alt + GPS + telemetry unit?

[denverdoc]

sign me up!

 

[ghost]

I'd love to beta test it, but how would you feel about me using it in MPR (like G64 powered) rockets?

 

[FROB]

I'd love to beta test it, but how would you feel about me using it in MPR (like G64 powered) rockets?

That's cool with me - you can conver a lot of ground in MPR or even LPR flights; but to validate dual deploy, staging,etc. and carry the weight of batteries, i expect it will need to be mostly MPR & HPR.

What's most important during beta testing is test coverage; it's easy for me to test the range of sensors and radio link.
What's hard to do alone is check all possible combinations and permutations of software configurations, with 'realistic' sensor input signals.
So i'll be asking Beta testers to fly as many different setups as possible, for as many flights as they can manage.
The beta units will be setup to log all 'raw' sensor data, which i will ask beta testers to download and email me (along with flight reports) so i can build up a library of test signals to do simulation testing with later. Over time this will make it a lot easier to validate new firmware versions without as much 'live' testing needed each time, and reduce the likelyhood of rocket carnage from it! :tomato:

I'm not taking names for Beta testers just yet - a lot can happen in the next few months before we're ready for first trials. But anyone who expresses interst now, of course, will get extra points for having faith and answering the call so quicky! :call2:

 

[ghost]

Cool!

I'd be able to do a bunch of MPR and a couple of HPR launches...

Also, I don't have access to BP, so I use Pyrodex instead. So I could test your system's ability to fire higher current e-matches (like the N3rd canisters)

anyways, I know you're not taking names just yet... but good luck and have fun developing it!

 

[snowman2]

I would prefer not having another "does everything" device. There is already an amazing number of recovery controllers available for such a small market. Several record data. Nearly all report altitude. Tiny altimeters that only report altitude are also available.

What I want is a GPS locator that's not tied to a recovery controller. All it has to do is transmit the last known coordinates. Some local people have built their own. I think the transmitter costs about $150.

I'd also like a more sophisticated, multiple event controller. It would be nice to have a controller that understands "up" so that events would only be initiated if a rocket is upright, such as airstarts and staging.

 

[FROB]

I would prefer not having another "does everything" device...
What I want is a GPS locator that's not tied to a recovery controller...
...I'd also like a more sophisticated, multiple event controller.
It would be nice to have a controller that understands "up" ...

Ok - so just to make sure i inderstand, you want:
1- A simple small GPS locator.
2- A more sophiticated controller that knows which way is up for staging etc.

It sounds like you want to keep the functions seperate - ok i get that - you may have some existing gear you want to use only function 1 or 2 with.

So what would you expect either (1) or (2) above should cost, each on their own?

 

[jderimig]

I would prefer not having another "does everything" device. There is already an amazing number of recovery controllers available for such a small market. Several record data. Nearly all report altitude. Tiny altimeters that only report altitude are also available.

What I want is a GPS locator that's not tied to a recovery controller. All it has to do is transmit the last known coordinates. Some local people have built their own. I think the transmitter costs about $150.

You can use APRS now (Ham license required). Beeline or Byonics
https://www.byonics.com/microtrak/mt300.php

I prefer BigRedBee because its 430 Mhz versus 144 for most of the APRS gear.

 

[rdh8]

Thats REALLY cool!

Has it flown yet?

Nope.
Maybe in the spring.

 

[ghost]

Ok - so just to make sure i inderstand, you want:
1- A simple small GPS locator.
2- A more sophiticated controller that knows which way is up for staging etc.

It sounds like you want to keep the functions seperate - ok i get that - you may have some existing gear you want to use only function 1 or 2 with.

So what would you expect either (1) or (2) above should cost, each on their own?

For the GPS locator (the part that goes in the rocket), I'd want to spend around $100 (so you can compete with the Rocket Hunter people). I don't know if this is possible, but if so, then that would be great.
For the GPS base station (plugs into your computer), I'd want to spend $100 or less. I think this is possible because all you would need is a RF receiver, a PIC, and a USB/Serial port.

For the sophisticated controller, here's an idea:
Create a basic board that holds your microcontroller and A/D converters and 3 PYRO outputs (sell it at around $100). There would be absolutely no sensors on this board. Then, you can sell sensor add-ons (tilt sensors, pressure sensors, gyros, accelerometers, etc). These can then easily plug into the microcontroller board (see each one around $20-50). Then, the board can be fully programmable (but you would have to make an EZ programming interface). To program, a program could pop up where you select the plugged in chips, tell the program what input they are in on the motherboard, and ask how many events per sensor, and have the user enter the event at the user defined point.

This is my dream complex flight computer/GPS setup

 

[denverdoc]

Status update: i've started the design work;
To make life easier for devellopment the inital boards (beta units) will be a little bigger; roughly 28mm wide and 3" long.
Thats because it saves time in layout to spread things apart a little,
and the same board with a few different parts loaded will serve as both "basic" ground unit, as well as flight unit.
Also for the Betas only 3 or 4 of AAA or AA alkaline cells (or 1 6V lithium camera cell) will be supported, no rechargeables, no 9V , but if you want more voltage for the e-matches, you can hook up a second battery for those.
Chances are, there will also be an additional option for a 2-axis rate gyro and 3-axis low-G accelerometer. This is primarily for use in staging, for the purpose of preventing upper-stage ignition in unsafe 'attitudes' ( a requirement in Canada) It might also be usable to detect apogee, but this is highly experimental, and will not be included in the first round of beta units.
I'm also working on a seperate 'add-on' module that does only this safety function. If anyone's interested in that, i can start a seperate thread to discuss it.

I've also decided to mount the pressure sensor on its own little remote mini-board, along with a safety-arm pushbutton, 2 led's, and a tiny buzzer.
You drill a 1/8" hole on the side of the BT, and mount this little board behind it on the inside, with the button in the hole.
This little board will be about 1"x1/2"; the (very small) pressure sensor will have a small piece of black felt glued to it to damp the 'noize' from the rushing air, and block daylight which can actually cause erroneous readings.
The reccomended mounting method will likely be like this:
- cut a piece of masking tape 2"x1" or larger;
- center it on the back side of the board;
- place it inside the tube, over the pre-drilled hole;
- smooth down the tape around all sides;
- cut a piece of 6oz fiberglass 3"x2" and epoxy it over the board (use 5-15 min. epoxy) making sure to work epoxy between and behind ribbon cable and bosy tube;
- hold it with the 4-wire ribbon cable pointing down while epoxy gels.
- voila!

The benefits are this:
- very rapid /accurate response for altitude measurement and instantaneous apogee detection.
- no more guesstimating the appropriate size and number of vent holes
- vent holes AND arm switch can be anywhere convenient, even in chute bays or low in the tail of the rocket
- allows flight unit to be mounted inside nose cone, with barometer holes at the base of the NC or in a chute bay below it for example
- no more worries about ejection pressure leaking into altimeter bay and messing up altimeter readings or damaging the pressure sensor
- there is always clear audible AND visual confirmation of recovery system armed/disarmed/operating, and continuity of the outputs.
- arm switch is easily acessible for someone finding the rocket - instructions can be printed on a sticker to be placed near it such as:

DANGER!
DISARM RECOVERY SYSTEM BEFORE MOVING OR HANDLING ROCKET
TO DISARM, PRESS THIS BUTTON FOR 2 SECONDS ==>(O)
SOUNDER WILL STOP BEEPING AND LED WILL BLINK GREEN WHEN DISARMED


If you want to be able to use the flight unit with several different rockets, you can buy additional "mini-boards" for somewhere around $25.


The telemetry antenna will be a wire extending from the top edge of the board.
The GPS antenna is centered on a 29mm dia PCB disk (ground plane), mounted at the bottom edge of the board, at right angles to it, with the main board attached so the center of the bottom edge is at the center of the disk.
The GPS ant. ground plane will have 6 holes along its edges, which can be used to scew it to a protective canister, or nose cone base, as well as a notch to allow mini-board and/or e-match leads to get past it and to the output teminal block, which is right behind it.

The flight unit should be mounted such that when under chute, the telemetry antenna points down and the GPS antenna points up.
I will probably make the GPS antenna "disk" detachable, so it can be mounted remotely if it is more convenient, for example for larger, or carbon fiber airframes that attenuate the signal too much. A simple 4-wire ribbon cable several feet long can be used for this purpose.
If it turns out most people will want to remote-mount the GPS, i will include that cable with the flight unit. In that case, how long would it need to be?

If anyone has any thoughts on these 'configuration' detials, i'd love to hear it.

I plan to make four beta units available in the spring.
He're is how i'm thinking or running the beta test program:
Beta units will be given on loan for 12 months for free.
Beta testers will be required to log at least 15 flights with it over the next 6 months.
Beta testers that complete 15 or more documented flights receive a 50% discount on one production 'set' of their choice.
Beta testers that complete 30 or more documented flights are entitled to a free flight unit and 50% discount on the ground unit of their choice.
If a beta unit is damaged or destroyed in flight for reason beyond your control (Cato or recovery malfunction for example), it will be replaced for free, as long as it (or its remains) are returned for forensic analysis; A beta tester who's rocket suffers $200 or more of damage to a rocket as a result of obvious beta unit malfunction, will be entitled to receive a 'deluxe' production set at no charge, if they first complete the beta program (15 or more documented flights)

Does that sound fair?

Now that I have some time, here are some random thoughts:

If i understand the remore feature correctly, the idea is to essentially pot the sensor to the side of the AF so that it is completely isolated from any ejection gasses while providing an unrestricted look at the ambient pressure. Therefore as planned one needs a new sensor board for every rocket or at the very least every AF size. Also because of the ribbon cable, ejection always needs to be in the direction away from that of the cable and motherboard. 25 bucks per sensor board.

The proposd benefits include elimination of any additional air vents since the baro sensor is now essentially on the outside of the rocket, rapid response time as it eliminates the RC type filtering, and a built in arming switch assembly, thus precluding the need for other switch arrangements.

The disadvantages I see are:

1) extra cost--I certainly don't have the wherewithal to have a dedicated altimeter for every rocket nor know too many that do, but at $25 its a relatively small cost compared to the main board/rocket.
2) For complex rockets where one may choose to use redundant electronics, many of the advantages are lost as the conventional electronics will require all the usual fuss. This also applies to the beta phase--I for one would not fly it initially w/o some backup, others may be braver. Also if one chooses to use say nosecone mounting for the GPS, it then means on account of the cable, that the antenna is still confined within the airframe. Here you mention having a second cable--maybe you can diagram the two cables in use together so I can better understand the options.


Now having said this it would be the answer to my prayers for at least one project I am working on--comparing nose cone shapes in high performance rockets. These will be 29, 38, and 54 and hence the need to use non rechargeable batteries. I've come to prefer using small "flight packs" of baby NiCads that carry a bit less voltage per cell, but whose high output obviates the need for extra cells to prevent brown-out.

Finally, I would hope that as configured one can elect to use gee based apo deploy. This IMO is better than having mach delays.

 

[snowman2]

1- A simple small GPS locator.
2- A more sophiticated controller that knows which way is up for staging etc.

So what would you expect either (1) or (2) above should cost, each on their own?

I hope you realize that asking what I think something should cost is not the same as asking what price I am willing to pay.

I think a transmitter should cost about $100 and have a battery life > 4 hours. I think a receiver should not cost more than $200.

What standalone systems are on the market that do not require a HAM license? Eage Tree Systems has a $600 system. Garmin has a $600 dog (or rocket) tracking system. The Garmin transmitter has a long battery life but the unit is larger than desired. The price seems to be $600 at this time. The R-DAS and ARTS GPS accessories are in that price range, too.

If the transmitter price is low enough a club could buy a receiver and individuals buy the transmitters.

 

[denverdoc]

thats a very good idea re the club/individuals sharing cost--may even make the xmitters rentable as our club does now for motor hardware.

Can you give a link to the Garmin? If its the rhino system, it is way less than practical last time I looked into it.

 

[jderimig]

thats a very good idea re the club/individuals sharing cost--may even make the xmitters rentable as our club does now for motor hardware.

Can you give a link to the Garmin? If its the rhino system, it is way less than practical last time I looked into it.

Also you don't have to be a HAM to own a receiver, and if you have a club HAM, you could put HIS transmitter in your rocket as long he is on site to control the unit.

The HAM issue is not that big of a hurdle.

 

[sylvie369]

The HAM issue is not that big of a hurdle.

It's very inexpensive to get the Tech license, and if you're technically adept enough to properly handle a GPS tracker/receiver, you should certainly be able to pass the Tech exam. I know only half of what you guys know about this stuff, and I managed it without too much trouble.

 

[FROB]

The disadvantages I see are:
1) extra cost--I certainly don't have the wherewithal to have a dedicated altimeter for every rocket nor know too many that do, but at $25 its a relatively small cost compared to the main board/rocket.
2) For complex rockets where one may choose to use redundant electronics, many of the advantages are lost as the conventional electronics will require all the usual fuss.

Good points.
On the extra cost, it doesnt have to be so, if you make the "mini-board" removable, but then that means moving it from rocket to rocket becomes more trouble so admittedly less attractive. What i could do is make the "mini-board" a snap-off section of the main board - if you dont want to remote mount it, leave it 'whole', and wire the controller in the traditional way.
This way you have the choice.

Also if one chooses to use say nosecone mounting for the GPS, it then means on account of the cable, that the antenna is still confined within the airframe. Here you mention having a second cable--maybe you can diagram the two cables in use together so I can better understand the options.

Remember the board is quite small;
all of it, antenna included, is expected to fit inside a 29mm nose cone- worst case, with the GPS antenna end extending slightly into the body tube past the shoulder.
In this case, the GPS cable isnt needed, and the mini-board can be mounted anywhere convenient if not using Baro apogee detection, or near the base of the N/C (assuming it is made with a 'straight' section to allow the appropriate airflow needed for a baro sensor) you can shorten the cable to just allow easy access to the controller as needed.
In such a case as well, if the body tube is conductive, you might not get GPS lock until deployment (apogee?) but you will have telemetry data all the way up and down.
In any large nose cone, this wouldnt be a problem.
You could mount the GPS 'module' deep inside the N/C, then mount the board on the base of the it for example, for easy access, or in an e-bay just below it for a more conventional arrangement.

When remote mounting the sensor or GPS unit, (or telemetry antenna, if you wish) all 'remotes' connect directly to the controller 'main' board.

Is that a little easier to picture?

 

[denverdoc]

yea that makes sense--I was getting tied up thinking the baro sensor would necessarily be potted say 12 inches (4" diameter rocket) down the top section of tubing and communicating with the main board in the cone, so you couldn't pop the cone and the antenna then would be stuck inside on the way down. But I like idea of the snap off option--then as you suggest, the GPS and baro sensor can be in close proximity if one chose not to use the remote sensing option.

 

[FROB]

I thought i should post a quick update -
The schematic and over 50% of the layout is complete.
As usual, i couldn't resist the temptation to squeeze it down as small as i could make it.

So right now, the main board is 3.2" long by 0.78" wide, or 82x20mm, 1mm thick. The highest point is the shield for the radio, ~ 4mm
This contains the CPU, 50G linear accelerometer, a 3D, 2-8G accelerometer, serial eeprom, some power management, and the radio transceiver.
I'm not quite done layout the power management bits, so it may yet grow in length 1/4" to 1/2". I was hoping to keep it to 2 layers, but its too dense for that, though i might still be able to get away with 2 layers for the prototypes with a few well placed bits of wire- crude and ugly, but sometimes much cheaper (and quicker) for 1 or 2 test boards. Final boards will be 4 layers.

A new twist: this board does not contain terminals or high-current output circuitry. Those will be on a smaller card, shorter and slightly wider, which connects to the main board via a card-edge connector.
The 'connector-interface board' is about 2" long and just under 29mm wide.
the main board will snap into the this one, which will be available seperately at low cost. This is to allow quick and easy tranfer of the "main board" from one airframe to another, without having to mess with the wiring. One screw will hold it in place.
If anyone *really* needs to make it fit in a rocket smaller than 29mm, and use it for deployment too, it would be possible to make a smaller 'ematch driver' board to connect on the same cable as the baro board, but i'm not planning to make one yet unless someone speaks up about it. otherwise if you just want to use it as a GPS tracker you can wire battery leads directly to the main board and not use the wider 'connector' base-board.

Future versions of the 'connector-interface board' will contain various exerimental sensors such as rate gyros, which can be used to detect rocket orientation, and serve to insure safe staging in multistage rockets. I am also considering adding servo outputs to experiment with active spin-reduction etc for aerial videos... later.

The 'remote' board with the baro sensor, switch, speaker etc. is 0.6" wide and 1.2" long. i may make it a tad longer to add screw holes. It turns out this can't be a snap-off option, but i will make it possible to snap it directly onto the 'main' board stack without a cable for those that perfer it together.

The GPS board is a disk 29mm dia, with the antenna on one side (plastic 'pill' about 16mm dia and 8mm high) and the circuitry on the bottom. This can be connected directly on the short edge of the 'main' board opposite the telemetry radio end (perpendicular) of with a ribbon cable.
If needed, the board can be 'trimmed' to fit in a 24mm rocket, but its possible the reduced ground plane will have some detrimental effect on GPS sensitivity - this needs to be tested later to see if this is negligible or not.

There will be 2 power source options: 5-12V, for example from USB port or 9V battery, or a 1.5-3V battery. if both are connected at the same time, power is drawn from the higher voltage source only. So if you don't need power for ematches, you should be able to run it off a single AAA alkaline cell. If you have low current ematches, you can use a small 3V '123' camera battery for everything, so its usable with smaller low power rockets too. Or go the usual route and run everything off a 9V or larger battery, or my preference for larger HPR rockets, use 1 or 2 2AA cells for the electronics and a seperate battery pack for the ematches. Once prototypes are built and tested, i will be able to tell how long you can expect different batterie choices to last in typical use.

The 'main' board contains everything necessary to act as the ground receiver of a tracking system, so the typical 'set' includes 2 of these boards, though one would not have the accelerometer or extra memory installed. by having the edge-connetor, you will be able to "upgrade" the basic receiver
to a "deluxe" version with an add-on card with the LCD and other fancy features on it ( and a nice enclosure to go with it)

The same board will also form the heart of a wireless launch system i've also been tasked to build for my club. As you can see, i'm a big fan of 'design reuse' That way i get a lot more mileage from the effort put into it, and hopefully, all these 'add-on' uses for the board will eventually make it a better value for everyone.

The plan is to hopefully have the design ready to send out to fab between xmass & new year's, and that means i could have boards assembled and working sometime in February,( of course i will post pictures) for a couple of months of code devellopment over the worst of the winter- though it seems we're already in it now, in these parts anyway!

Have a safe and happy holidays !:santaclaus:
:beer: arty: :marchmellow: :ciao: :tee: :dancing2:

 

[FROB]

90% done with layout, and counting....
I may be able to sqeeze in some terminals and 4-5A ematch drive circuits on the main board after all - not all the features of the 2-card option, but simpler and more economical if that's your priority.
Last call for comments & feature request....

 

[Rockstone]

isn't it illegal to have gps trackers?
Doesnt that make it a missle?

 

[ghost]

:surprised: tracker as in a person on the ground tracks it............

 

[Rockstone]

ahh, so you can track it, but you cant change its direction!