New Flight Computer - would you be interested?

Here is the link to the relevant LIPD Class Licence in Australia if you are interested. 868MHz is a no-show in it I'm afraid :
https://www.legislation.gov.au/Details/F2016C00432
A lot of trackers operate under items 54 and 58 of Schedule 1.

watheyak said:

It has nothing to do with the GPS being "crummy". Please refrain from talking about things you don't know about.

In a minimum diameter rocket with limited space I want anything but a wire antenna that needs to be kept straight. Ducky all day long...

Besides, the antenna on the featherweight is not integrated, it's attached by an SMA connector.

Click to expand...

One thing I did with a Wildman Jr is run the Beeline GPS wire antenna directly through a formfit hole in the forward bulkhead into the '
main chute bay. Huh? You say. How do I keep the wire from getting scrunched by the parachute laundry? Simple I use a cardboard tube as a stent! The same tube that the AT wired (firstfire?) ignitors come in! Works like a charm. The wire is sideways just a hair but has done well for 16 flights all sight unseen.
A little clay on the bulkhead prevents eject charge leaks into the bay and if I lose the stent, so what, I get plenty with reloads!
Holee guacamole! I didn't realize there were so many doing 70cm Ham band tracking out there.
I thought I was one of a very few. Everything that's been said is true. If one has the room to do 2 meters an AP510 tracker https://dk7xe.blogspot.com/2014/09/ap510-avrt5-aprs-tracker.html
for $109.00 is workable if one doesn't mind the steep learning curve. 1Watt output and one will have to make sure it doesn't interfere with their electronics.
There's this one too: https://www.hamradio.com/detail.cfm?pid=H0-015928#
Costs more. None of these would work for record attempts but can take advantage of the 2 meter band. Can be tuned off the National APRS frequency of 144.390 so not to interfere with the network. I like to set mine to transmit once every 5 seconds Kurt

Andrew_ASC said:

The TeleGPS v1.6.8 handles a G load of 68G’s for university flight and tracked the entire flight during boost through landing etc. Telemetry has voice announcements. Tried it at 168G’s once for another university project and we ended up ordering a second unit. So all electronics have limits. GPS seem particularly sensitive to G loading and Mach numbers. I’m just a mechanical student. We recovered rockets through tree lines and over light 200ft terrain obstacles with 440MHz. Not certain a 900 MHz unit could do that over 1.8 km away. Treeline was dense. I’m sure the community would enjoy a lower priced 900 MHz variant.

Click to expand...

That's my emphasis in the quote above. I spotted the highlighted sentence and had to bring it up. Andrew, please don't limit yourself with your thinking. There are many things that can be learned to a reasonable degree, without having to absolutely know the fine detail. You are learning mech eng currently, but I would advise you to study areas outside your own bailiwick when possible, so you become a better engineer. A good engineer has a reasonable understanding of quite disparate disciplines which enables them to interact better within multidisciplinary teams who work together for a goal (say designing a product or something). This is something I feel strongly about that engineers need to strive for, and it makes for better outcomes and stronger teams. An ideal outcome would be to have the required skills for being a System Engineer. They are key to getting all the individual subsystems integrated and interacting properly together. They catch things that the usual single-discipline engineers miss.

Since you are in your degree currently, that is obviously priority #1 now, but after it is over continue the journey. You will find it is not so much about what you have been taught, but that they have will have taught you a way to learn.


There is always new stuff to learn. To anyone out there, please shoot me when I stop learning.

OverTheTop said:

There is always new stuff to learn. To anyone out there, please shoot me when I stop learning.

Click to expand...

when I stop learning it will because I am dead.. no one will have to shoot me...

Eric said:

What are you looking at for a current price point?
And in the US, I dont think 868mhz is in our license free band

Click to expand...

In europe it is 868 MHz and in US 900 MHz. So for the "US-Version" I would change the module and antenna.

But first of all I have to go into deeper testing with the frequencies and modules I have here.

Target price should be <300 $ for the main unit...but don´t know if I can reach this.
Depends much on the quantity...

Well, for a rocket that I would want tracking and telemetry on 1000 meters is not nearly far enough. Good data storage onboard would help, but I would need a separate GPS tracker with more range.

Laptop dongle would be a deal breaker for me, also. Either standalone receiver or Bluetooth to a smartphone/tablet would be much better.

My two cents worth...

LoRa chips work great for telemetry. I have had no problems at over 3.5 miles on 20 mW power. I'm confident that it would have had over 10 miles+ line-of-sight range based on the signal strength I was receiving.

Hey stomper, there's been a few people in this thread who've made the point that I'm about to make already, so I won't harp too long.

The market for high end altimeters is agonizingly small. We're almost on the 4th gen raven and I don't believe they've sold more than about 6k of them between all generations.

If you're looking to make this for yourself, I understand completely. Hell making a few of them at once is really the only logical way to do it! Might as well sell a few and help with the costs. Just remember that you're selling to a market so small that the largest of our events has maybe 300 fliers or so. AirFest only had 200 preregister this year. Think about how many you'll have to sell in order to break even, now think about how much money people are risking by using your "newfangled" hardware. Very rarely are we launching less than 20 hours of our build time and a crap load of money.

Altimeters have to earn peoples' trust before they're widely accepted. That said, Rocket people are inherent risk takers (with a lot of analysis beforehand) so I've not doubt you'll get some early adopters. Just don't expect a runaway success or really to break-even at all. lol

The newcomers who tend to have success are selling extremely refined, simple and effective devices. The Jolly Logic Chute Release is probably the greatest thing to happen in rocketry since sliced bread. I wish they'd get into proper high power stuff.

cwbullet said:

That being said, there is a much larger market for 900mhz.

Click to expand...

Right, no license required, high performance LoRa chips for it available, smaller antenna including the gain antenna, if used, at the ground station end.

Stomper said:

I am an electronics engineer and I am planning to build a professional flight computer for model rocket enthusiasts.

Click to expand...

The more choices for onboard electronics, the merrier. Please record and store all flight orientation data like roll, yaw, and pitch for flight dynamics analysis. Also, the quality and ease of use of data processing software will be important.

I would be very interested in this. I was into Drone racing for a while, checkout the Naze32 Full flight controller for drones. Hardware-wise it has just about everything you mention onboard or available except for the radio. I've put together my own flight controller package using a raspberry pi zero w and a couple breakout boards. It works and is pretty cool but heavier and larger than my drone flight controller board.

My plan is to take the Naze32 off my drone and reprogram it for rockets. Eventually I want to work on active stabilization and the drone flight controller is much better equipped to handle that kind of task than a general purpose computer like the pi.

Stomper,

As others have pointed out, your ideas are good for creating interest, but market capitalization may end up quite limited.

Just FYI, twenty years ago Dave Triano offered a custom CPU based timer called the XTime. It was highly ruggedized and configured with external dimensions of 5" long, 1" wide, and .5" deep to fit a 38mm tube.

The Xtime had only a small fraction of the capabilities you are proposing, and each unit was custom built to order. This was 20 years ago and much has changed since then. The cost at that time was $325 each.

So I would be interested to know what your cost target is going to be, and will your unit be a production item or another custom built to order approach.

Eric said:

What are you looking at for a current price point?
And in the US, I dont think 868mhz is in our license free band

Click to expand...

The module I want to use is 868 MHz AND 900 MHz... so it is usable in both areas. Needs just one parameter to change.

pendrin2020 said:

Hey stomper, there's been a few people in this thread who've made the point that I'm about to make already, so I won't harp too long.
...
simple and effective devices. The Jolly Logic Chute Release is probably the greatest thing to happen in rocketry since sliced bread. I wish they'd get into proper high power stuff.

Click to expand...

Don´t be concerned... It is more or less for myselfe. The most parts of the electronic I do need in another projekt. But befor starting this other project I need to learn a little bit about the components.

I am no daydreamer. I know that this will not become a very great selling product :-D As you wrote... I try to get some money back for the developement. The software will be open source, so everyone can change and re-engineer it.

Winston said:

The more choices for onboard electronics, the merrier. Please record and store all flight orientation data like roll, yaw, and pitch for flight dynamics analysis. Also, the quality and ease of use of data processing software will be important.

Click to expand...

There will be a IMU with 9 DOF (Acc, Gyro, Magnet) to determine the exact orientation. And one additional High-G Acc up to 200 G to measure the acceleration during start.

Blackleaf99 said:

Stomper,

As others have pointed out, your ideas are good for creating interest, but market capitalization may end up quite limited.

Just FYI, twenty years ago Dave Triano offered a custom CPU based timer called the XTime. It was highly ruggedized and configured with external dimensions of 5" long, 1" wide, and .5" deep to fit a 38mm tube.

The Xtime had only a small fraction of the capabilities you are proposing, and each unit was custom built to order. This was 20 years ago and much has changed since then. The cost at that time was $325 each.

So I would be interested to know what your cost target is going to be, and will your unit be a production item or another custom built to order approach.

Click to expand...

The hardware is nearly ready to be produced (at least the first B sample). This is very expensive as there are a lot of options on it, witch is to test and to get to know everything for the later product.

The final board will be in the 300 USD Range... hopefully I get it down to 250 USD...without any Software.
The board itself is professionally manufactured and assembled in China from a partner Company of mine. Tested and engineered in Germany.
It has an SWD/JTAG connector and everyone may add software to it.

The Software I need for my own rocket and my other project, will be available for free - as mentioned: Open Source.
The underlying System will be FreeRTOS and the STCubeMX Library from ST Microelectronics.

I don´t know if I have the time to write a nice and smooth firmware for the board so everyone can use it without knowledge of programming.
I cannot guarantee that this will ever be available. At least not without any help from other people.

What I can imagine is an board to be an open platform for everyone to write code.
And building a website with all the information and code on it. Like Arduino and others do.
Maybe there will build up a software community around the hardware. :-D

If someone is interested to help me with that... feel free to contact me.
I can provide webspace and a domain for an online community.

I will be back with the first 3D renderings of the board, as soon as layout process has finished.

Best regards
Stomper

There is the first shot....

Hey folks,

it has been a while and it was some time ago since my last post here. But I was not sleeping.

I was working on the first version of the electronic and now the first prototype is on my laboratory bench!!



Work is still in progress to fix the last bugs in hardware, but the goal for the first version is in sight.

The main features will be

Size is
140 mm long
28 mm wide
12 mm high

• I/Os
  • Micro USB to load battery
  • Battery connector to connect a LiPo battery
  • 3 LEDs to show Status
  • 4 ports for bridgewire detonators
  • Buzzer to warn if ignition is powered and ready to fire
  • SWD Connector to flash new firmware
• Modules
  • Battery charging unit to charge LiPo
  • Gyro
  • Acceleration sensor for low G
  • Acceleration sensor for high G up to 200g
  • Altimeter (+/- 5 m accuracy)
  • GNSS (GPS / Glonass/ Gallileo)
• Radio
  • LoRa WAN with up to 5000 m LOF radio connection
  • 868 MHz / 915 MHz band
  • Used just the PHY layer to be free in form of connection
  • no need of LoRa Gateway with LoRa Transport Layer, I use just a small eval board with USB to connect to PC
• Datalogging
  • Micro SD Card slot
  • HW ready to save a full set of data each 10 ms (100 Hz)
  • Saving orientation, roll rate, acceleration, height and GPS coordinates

This is what the hardware is able to deliver. At the moment I am coding on a small test software to test all the hardware.
During 2019 there will be a small software available to get this peace of hardware to work, but no complete software to satisfy all of your needs.
Everyone has to and can code by them self ... I can provide a board/forum to discuss and exchange software.
Or maybe we get a space in this forum...

The module is able to switch between 868 MHz for Europe and 915 MHz for US - no need to solder or to change anything. Its just software.

If there are enough people interested in the product, we can get this for a price of about 200 USD for the hardware
On top comes a cable to flash the firmware for about 5 USD
And a Firmware programmer from ST to flash the firmware for about 20 USD

To get this price I have to order at least 10 units at my company.

I expect the hardware to be ready by March and could ship it until end of April.

Are there some people interested in this?

Stomper said:

Hey folks,

it has been a while and it was some time ago since my last post here. But I was not sleeping.

I was working on the first version of the electronic and now the first prototype is on my laboratory bench!!

View attachment 372443

Work is still in progress to fix the last bugs in hardware, but the goal for the first version is in sight.

The main features will be

Size is
140 mm long
28 mm wide
12 mm high

• I/Os
  • Micro USB to load battery
  • Battery connector to connect a LiPo battery
  • 3 LEDs to show Status
  • 4 ports for bridgewire detonators
  • Buzzer to warn if ignition is powered and ready to fire
  • SWD Connector to flash new firmware
• Modules
  • Battery charging unit to charge LiPo
  • Gyro
  • Acceleration sensor for low G
  • Acceleration sensor for high G up to 200g
  • Altimeter (+/- 5 m accuracy)
  • GNSS (GPS / Glonass/ Gallileo)
• Radio
  • LoRa WAN with up to 5000 m LOF radio connection
  • 868 MHz / 915 MHz band
  • Used just the PHY layer to be free in form of connection
  • no need of LoRa Gateway with LoRa Transport Layer, I use just a small eval board with USB to connect to PC
• Datalogging
  • Micro SD Card slot
  • HW ready to save a full set of data each 10 ms (100 Hz)
  • Saving orientation, roll rate, acceleration, height and GPS coordinates

This is what the hardware is able to deliver. At the moment I am coding on a small test software to test all the hardware.
During 2019 there will be a small software available to get this peace of hardware to work, but no complete software to satisfy all of your needs.
Everyone has to and can code by them self ... I can provide a board/forum to discuss and exchange software.
Or maybe we get a space in this forum...

The module is able to switch between 868 MHz for Europe and 915 MHz for US - no need to solder or to change anything. Its just software.

If there are enough people interested in the product, we can get this for a price of about 200 USD for the hardware
On top comes a cable to flash the firmware for about 5 USD
And a Firmware programmer from ST to flash the firmware for about 20 USD

To get this price I have to order at least 10 units at my company.

I expect the hardware to be ready by March and could ship it until end of April.

Are there some people interested in this?

Click to expand...

This looks like an interesting project. What are you microcontroller are you using?

Subscribed. Thanks for sharing this project as you build the new product.

Correction... of course it is

• LoRa WAN with up to 5000 m LOS radio connection (line of sight)

At least I achieved this with a good antenna. It has to be tested with a small one for the rocket, but I guess it will achieve at least 1500 m LOS.

tHoagland said:

This looks like an interesting project. What are you microcontroller are you using?

Click to expand...

It is a complete LPWAN Module from Murata with an underlying STM32L0 controller. The Murata module is an open platform and some of the pins of the stm32 are routed out of the module to use them for other purposes. This safes money and space... hopefully it has enough flash memory...

Stomper said:

4 ports for bridgewire detonators

Click to expand...

Stomper please be careful about using specific nomenclature like this

• 4 ports for bridgewire detonators

Hi Blackleaf,

what do you mean by "be careful about using specific nomenclature" ?

I am no native english speaker, so maybe I use words wrong... should I better say bridgewire igniter ?

Basically there are just 4 high current outputs with low-side switch. 0.5 A continuous and 1.5 Amps peak.

Best regards
Stomper

Yes, igniter is a better word as the other word sounds like you are making something a terrorist would use.

Stomper said:

Hi Blackleaf,

what do you mean by "be careful about using specific nomenclature" ?

I am no native english speaker, so maybe I use words wrong... should I better say bridgewire igniter ?

Basically there are just 4 high current outputs with low-side switch. 0.5 A continuous and 1.5 Amps peak.

Best regards
Stomper

Click to expand...

==================================================
I understand your desire for language clarification. It may be better to describe the output signal characteristics rather than the intended load. Something like, '4 high current short duration DC voltage outputs' should be enough for anyone to clearly understand its intended purpose. At least that would be understandable to anyone intelligent enough to purchase your new flight computer.

As Zeus-cat pointed out, it is better to remain more or less neutral in defining who would/could use that output signal.

Stomper said:

Basically there are just 4 high current outputs with low-side switch. 0.5 A continuous and 1.5 Amps peak.

Click to expand...

Sometimes unsolicited advise is not welcome, but this driver switch is a little under sized. 1.5Amps can easily be achieved with many batteries and matches/starters and if driver(s) get over currented and shorts (which is what it will do); The next time power is turned on, the result may be undesirable.

Stomper said:

continuous and 1.5 Amps peak.

Best regards
Stomper

Click to expand...

That is not enough.

OverTheTop said:

Some extra channels that can be used to measure and record analogy voltages with the other flight data. The TeleMega I use has a total of six pyro channels, but I only use two for deployment. The other four can be fed analog voltages from other sensors and systems for recording. I use this for logging servo positions when flying my VTS and for monitoring the other altimeter batteries during other flights. I could use more than the four spare if they were available.

Click to expand...

As my question mark logo indicates, my knowledge is questionable... Is VTS Joe's vectored thrust stuff? Does that use analog servo's. Seems odd.

BLH said:

As my question mark logo indicates, my knowledge is questionable... Is VTS Joe's vectored thrust stuff? Does that use analog servo's. Seems odd.

Click to expand...

Search for VTS in TRF or on the Australian Rocketry Forum and you will find my Vertical Trajectory System. Here is the build thread: https://forum.ausrocketry.com/viewtopic.php?f=56&t=5324

The electronics do a frame-by-frame conversion of pulse width to voltage and I feed that into unused deployment channels on the telemetry for transmission and logging, all synchronous with the rest of the flight data.

OverTheTop said:

View attachment 373403
Search for VTS in TRF or on the Australian Rocketry Forum and you will find my Vertical Trajectory System. Here is the build thread: https://forum.ausrocketry.com/viewtopic.php?f=56&t=5324

The electronics do a frame-by-frame conversion of pulse width to voltage and I feed that into unused deployment channels on the telemetry for transmission and logging, all synchronous with the rest of the flight data.

Click to expand...

Hate to change subject on this thread... So this is all I have. Your VTS is really cool. I have allot of control experience on high speed rockets and I would suggest not to try super sonic with RC servos (update rate is too slow). Only bad things will happen. You will need really high speed sampling, control and compliant actuators. I think with the new vectored thrust stuff, Joe is finding the same things....

Still really cool! Good luck.

If I keep the system gain down low enough the servo response time is not problematic, even for supersonic. As it stands it does stabilise to a vector (but not vertical due to reference frame trimming on the COTS electronics) but unfortunately that is not vertical . I will switch to different electronics that I can tweak the firmware in for the next incarnation. Better airflow over the aft section of the rocket, by using strakes, would be an improvement also.

So you can see what I use the four channels for anyway. Logging analog voltages can be quite useful, and a good general-purpose interface.

OverTheTop said:

If I keep the system gain down low enough the servo response time is not problematic, even for supersonic. As it stands it does stabilise to a vector (but not vertical due to reference frame trimming on the COTS electronics) but unfortunately that is not vertical . I will switch to different electronics that I can tweak the firmware in for the next incarnation. Better airflow over the aft section of the rocket, by using strakes, would be an improvement also.

So you can see what I use the four channels for anyway. Logging analog voltages can be quite useful, and a good general-purpose interface.

Click to expand...

Very Nice! Per this side tangent, adding a couple of analog input channels may be something no one else is doing with flight computers...