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  #21  
Old 07-11-2021, 07:39 AM
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Earl Earl is offline
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Quote:
Originally Posted by BEC
He'd have to correct me, but I think it was his brother who was more into electronics than Vern himself was.


I think you are correct on that. I seem to recall his brother’s name is Earl. Hmmm...wonder how I happened to remember that detail....

Not sure who did help develop the Transroc, but on the OP’s conjecture, I don’t believe Vern had a son, did he?

Earl
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  #22  
Old 08-30-2021, 07:44 PM
fuzzoli fuzzoli is offline
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The journey is complete! The last couple of weeks have been spent building up the "final" incarnation of the transmitter. I now have a (mostly) historically accurate, fully working Transroc.

From a technical perspective, here's where the time was spent.

First of course, was winding the coils. I know I had photos of completed coils in my last post, but as I was ordering boards for another project, I added some Transroc boards to my JLCPCB order. These latest boards are more historically accurate as they have the solder mask across the entire board (as opposed to just the copper in the previous post). Getting new boards also gave me the opportunity to streamline my build notes. While tapping the coil forms, I did learn one good lesson -- make sure the threads are all the way through the form, and DON'T force the slug through the form -- if the slug binds, run the tap through a few more times to clean up the threads. I learned this the hard way, and now have a cracked slug for the trash bin. :-(

With the coils wound, it was time to place the first component! The assembly order followed the original Transroc manual for the most part with a couple of exceptions. I built this as I built the breadboard version, and that means the Modulator was assembled and tested first. Once that section was verified, the RF Section was added and tested.

As the 15v "Eveready 504" batteries are over $10 USD a piece, all testing was done with my new EEZ BB3 Bench Power Supply .

The Transroc can be built in several configurations:

Rocket Finder - Pulses the transmitter once every second or so.
Temperature - Uses a thermistor to modulate the transmitter at an audible frequency.
Spin Rate - Uses a photocell to modulate the transmitter at an audible frquencey.
Microphone Mode - Sends back audio of your rocket in flight.


This incarnation was build in Spin Rate mode. I felt Spin Rate would give the most useful data. Here is a quick video of the Transroc in action. Turn your volume down -- the tone is a bit nails-on-the-chalkboard! The audio is from a walkie talkie just out of view. You can hear the varying tone as the photocell sees more and less light. It was pretty cool to hear this for the first time!

The obvious final step is to actually fly this thing and analyze the data. It's definitely on the list, and I'm building out a custom rocket for the event. It should be fun!

So What's Next

Over the next couple of weeks I'll be getting all of the files and build notes up to GitHub. I'll post the link here once I get most of the files posted.

Can you build one? Absolutely! After dealing with modern circuit boards and 0406 SMD parts, this project is relatively tame. Most parts are commonly available either through standard channels or via eBay. The coil slugs are samples graciously sent by the manufacturer Micrometals . I don't know what they cost in single quantities, but perhaps if there's enough interest, I could see if they'll be up to a small purchase. The boards are literally pennies to produce, and shipping ends up being more than the boards. I did order a bunch of extras, so PM me if you'd like one.

The Future

In my original post, I mentioned a possible future. Assuming this recreation went well, wouldn't it be neat to see how much telemetry we could get, using modern parts, packed into the same volume as the original Transroc. LiPo batteries are small and light, and there are tons of sensors out there that could be crammed into the ~2.75 in3 of available space. ...not sure when that project will start as I have a few other projects in mid-flight, but I have a feeling I won't be able to stay away from the modern challenge for long.

Thanks for all the kind words from folks on this forum who have followed me throughout this eight month journey!

Stay safe!
-Frank
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  #23  
Old 08-30-2021, 08:36 PM
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Earl Earl is offline
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And again: Wow! I really admire your dedication and determination to bring this to a working reality! Very, very commendable!! I’ve got an old built one that I picked up off eBay probably 8-9 years ago, but have not tried to power it up. Never had one back in the day, but thought that it would have been a neat thing to at least try once.

Great job! And yes, that tone in the video is a screecher!

Earl
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  #24  
Old 08-30-2021, 09:35 PM
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rocketguy101 rocketguy101 is offline
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Great job, and I've enjoyed following your journey...I do have a question. ISTR back in 72 or so, the Estes rep that attended the Southwestern Model Rocketry Conference in Albuquerque NM (I think it was Dane Boles??) demo'd specially modified Transroc that allowed changing out the various modules by just plugging and unplugging boards to the main board, much like the Foxmitter that had been published in Model Rocketry magazine.

I always wished Estes had done the same for the production model, rather than having to solder/de-solder components to change the configurations. Do you see a way to do this? I am fairly certain I'm not imagining this as several attendees commented on in it.
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  #25  
Old 08-31-2021, 06:41 AM
fuzzoli fuzzoli is offline
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Quote:
Originally Posted by rocketguy101
...back in 72 or so, the Estes rep that attended the Southwestern Model Rocketry Conference in Albuquerque NM (I think it was Dane Boles??) demo'd specially modified Transroc that allowed changing out the various modules by just plugging and unplugging boards to the main board, much like the Foxmitter that had been published in Model Rocketry magazine.

I always wished Estes had done the same for the production model, rather than having to solder/de-solder components to change the configurations. Do you see a way to do this? I am fairly certain I'm not imagining this as several attendees commented on in it.


That would be a very cool modification! In analyzing the schematics over the months, it became apparent that there's very little difference between the various modules. The Microphone Mode parts can stay in for the most part, and the Rocketfinder, Spin Rate, and Temperature Modes are more-or-less identical other than the values of the timing components.

Therefore, it should be possible to rearrange the parts so that they're all in the same area of the board, and to include those differences on a plug-in module. I'd have to think about what kind of socket/pin arrangement they would have used back in the 70's (maybe take a look at what the Foxmitter did).

There's not a lot of room left with these parts being ginormous (compared to modern standards), but it would be a fun challenge! I'll have to think about it!
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  #26  
Old 08-31-2021, 06:21 PM
PaulK PaulK is offline
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This has been really interesting, I knew little about the transroc other than I couldn't afford it. Really nice work making such an accurate clone!
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  #27  
Old 10-04-2021, 08:02 PM
fuzzoli fuzzoli is offline
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The project is now up on GitHub at https://github.com/d5aa962e/Transroc​​​

As the transistors and coil slugs are hard to find, I have a very limited count of slugs, transistors, and boards available at my cost. PM me if interested.
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  #28  
Old 10-04-2021, 11:59 PM
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Leo Leo is offline
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This is a very cool project. Well done!
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