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Wally Ferrer

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No, I can't. You've sent me down a rabbit hole that led to reading up on the Australian pre-decimal coins. did you know that the crown fits nicely into a 38 mm MMT?

(It's odd, I'm not a coin collector, and never have been. But I can't help reading about systems of coinage: the denominations, alloys, dimensions, and occasional trivia.)
Coins in Ocean City Maryland has the best crabcakes.
 

jqavins

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(It's odd, I'm not a coin collector, and never have been. But I can't help reading about systems of coinage: the denominations, alloys, dimensions, and occasional trivia.)
Coins in Ocean City Maryland has the best crabcakes.
Crab, 80%
Brad crumbs, 10%
Onions, 5%
Crab juice, 3%
Vegetable oil, 2%
Seasonings, trace.

One of my favorite alloys.
 

Cape Byron

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No, I can't. You've sent me down a rabbit hole that led to reading up on the Australian pre-decimal coins. did you know that the crown fits nicely into a 38 mm MMT?

(It's odd, I'm not a coin collector, and never have been. But I can't help reading about systems of coinage: the denominations, alloys, dimensions, and occasional trivia.)
Ah, pre-decimal currency. We have a small collection.

Decimal currency came in on Valentines Day, 1966. In the lead up there was a television commercial an an animated dollar bill, imaginatively called 'Dollar Bill' and a pretty snappy jingle. We had a mix of decimal and pre-decimal coins in circulation for what seemed like years. Shop listed prices in both currencies.

People hated the new notes because they were much smaller than the old ones. Colourful, by the standards of the day, lead to the notes being treated as play money by many children.

If you have any crowns, their minimum value is about $75. Some fetch thousands.
 

jqavins

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New money Always looks like play mony to the people who are used to the old, and people always object to it. We introduced new paper money designs here quite some years ago now, with bigger portraits, a slightly different layout, and a little color; same size, material, and general design as before, and people went nuts. In time, as also always happens, people got used to them and no longer give them a thought or second look.

Longer ago, we introduced $2 bills that were so widely rejected that there are people today who'll think they're fake if they ever see one. (There have been arrests on very rare occasions.)

Our government would like to stop printing $1 bills, and go to dollar coins. The public objects, and the government gives in. How about introducing the dollar coins first so people can get used to them and then remove the bills? Nope, people reject the play money coins and the bills continue. There are about a billion $1 coins sitting in bags that Congress ordered made but no one wants.

How about introducing twos so we won't need as many ones? Nope they don't like the twos either.

We could stop printing ones if we'd do one simple thing: stop printing ones. As always, people would get over it and get used to the coins. I'd be happier if a $2 denomination also came out, be it paper or metal, because I'd rather not have so many 8 gram $1 coins in my pocket. (Actually, the law is still on the books that allows the printing of twos, and small runs of them have been made from time to time, so it'd be easy step that up. A new coin would have to be approved by Congress.)

OK, tirade complete. Sorry about that.
 

Cape Byron

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We have $1 and $2 coins, commonly referred to as 'gold coins' by people seeking a donation. They're about as close to gold as aluminium foil.

Interesting factoid: the coins most people get in change from cash purchases ends up in jars and on trays next to the car keys. Introducing a higher dollar value coin usually ends up removing a certain amount of circulating money from the economy. That's apparently why our $5 coin has been on hold for a few years. Learned me that from a high school economics student.
 

GrouchoDuke

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Masked & sprayed the color on the modified Hi-Flier XL I’m using as a test rocket for the paint job on my AI38. I’m definitely glad I did it with this “expendable” rocket first. I removed a lot of the extra detail from the design and it was still quite a bit of work to make it happen. The design wraps around the rocket more than once, so it takes some, umm, creativity to get on there.

The fine detail didn't do so well in a few spots. It was never meant to be perfect (seriously, it’s a $10 rocket that I did no prep on), but I think it looks pretty ok. Fun stuff!

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neil_w

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The design wraps around the rocket more than once, so it takes some, umm, creativity to get on there.
I hadn't even thought of that aspect... Could the mask cut into two pieces (an adventure unto itself) so that each piece is less or equal to one full wrap?

Would like to see video how you did that. :)
It was never meant to be perfect (seriously, it’s a $10 rocket), but I think it looks pretty ok. Fun stuff!
Looks better than "pretty ok" from where I sit...
 

GrouchoDuke

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I hadn't even thought of that aspect... Could the mask cut into two pieces (an adventure unto itself) so that each piece is less or equal to one full wrap?

Would like to see video how you did that. :)
Well, the design has some continuous parts that kind of swirl around the rocket. It was hard enough to get a single break in it. The design could change, but that's no fun. I could make another cut in it, but that edge probably won't look great on the final rocket. It's supposed to be hard - that's kinda the point I guess.

All of the unattached bits of the design (which I didn't include on this rocket) are already going to be on a separately applied mask...or maybe several of them. That'll help. It's a ton of little things to pick off though after shooting the paint!

Looks better than "pretty ok" from where I sit...
Thanks. :)
 

jqavins

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In Oz we have also eliminated the 1c and 2c coins. We are existing quite happily without them. Seeing how well that went I would be happy to see the 5c coins go as well.

Interestingly our $2 coin is smaller than the $1 coin.
Yeah, I saw that in the Wikipedia article. Canadia has the same as you, no 1¢, and there are both $1 and $2 coins. (I surprised a hotel desk clerk when I, and American, asked her to change some paper for "toonnies" for the laundry machines.) They don't have 2¢, but I don't think they ever did. I know that we in the US (OK some us) would also like get rid of pennies, but face the same resistance as to getting rid of singles.

The other thing weird about us, and Canadians, is that we have 25¢ coins, not 20¢. 1, 2, 5, repeated with powers of ten, is a pretty common sequence. Look at the currency of other countries and the dials of oscilloscopes and other places. Yet we have 1¢, 5¢, 10¢, 25¢, $1, $2, $5, $10, $20, $50, and $100. OK, 2¢ has been missing since 1873, 50¢ and $2 are all but obsolete (but still valid). But why the heck do we have 25¢ and not 20¢?

(I told you, I'm a coin geek.)
 

OverTheTop

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Got some parts 3D resin printed for the VTS. A stand for holding it while I am working on it, and a mount for the GPS receiver. Probably won't be able to fit the GPS till Sunday as we are going to be out and about enjoying our freedom after 14 days of isolation.
 

Adam3836

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Bought this cool box for my electronics and motor casings...... triple layer foam and 2 of the layers have small cut outs so you can pull and remove the foam to get the right size you want
Almost done.... got the 29 casing 3grain in just have to make the spot for my 38 casing now
 

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Cl(VII)

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Ordered some 2s lipos along with a 5V BEC for the RunTime Split 4 camera I have coming.

I also ordered a 4s lipo and a drone power distribution board to play around with. Sometimes I'd like to power multiple things off the same battery (yeah I know, you lose the battery redundancy), but they have different voltage requirements and current limits. I'd also like them to not electrically interfere with each other. I think this might be a nearly off the shelf way to do that as they have current limited 12v and 5v outputs along with four pads that are basically battery splitters rated for 25A.

I'm thinking the 5V and 12V pads (total 4) are the tracker, altimeter and camera pads. The 25A pads can be for an altimeter with current protection, or for separate pyro circuits. Everything could be run off the same switch when space is tight too...yeah, I know, redundancy. This is going to be a bench top experiment for now.
 

jqavins

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Can you sketch this out? Do you know how the two pads' voltages are derived? Honestly, I think running two things from the same battery would be much more likely to increase interference than to decrease it.
 

Cl(VII)

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Can you sketch this out? Do you know how the two pads' voltages are derived? Honestly, I think running two things from the same battery would be much more likely to increase interference than to decrease it.
I hear you, but part of what these boards are designed to do is minimize that interference in racing drones. Our stuff is pretty constant drain, especially compared to four drone motors. The exception would be on deployment charge firing, and that should be low current too with ematches unless there is a short. I'm doing this more in an effort to see how much I can cram into a small space than to reduce interference. I'm looking at it the other way, i.e. is the increased interference and loss of battery redundancy worth the space and wiring complexity savings in crammed electronics bays. When designing things to fit in 38mm rockets, the batteries are often the most frustrating part. I want to see if I can fit a camera, 2 altimeters and a tracker in one 38mm bay that is about 8" long...I think I can if this works, it will certainly be easier.

If nothing else it will be a cheap ($13) learning experience.


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jqavins

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It seems like both I misread something, and perhaps you misstated something else.
I also ordered a 4s lipo and a drone power distribution board to play around with.
[Underline added] My eyes skipped over that part, and I thought you were running off two taps from a series stack of cells. Which would surely increase noise linking between the two devices. But a dcent distribution board which has some sort of output buffering (like two entirely separate DC/DC converters) should give excellent isolation.
I'd also like them to not electrically interfere with each other.
Which makes it seem that noise reduction was your goal, or at least part of it. With the power distribution board you're still not getting any better than two separate batteries, but no worse either.
 

Cl(VII)

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It seems like both I misread something, and perhaps you misstated something else.[Underline added] My eyes skipped over that part, and I thought you were running off two taps from a series stack of cells. Which would surely increase noise linking between the two devices. But a dcent distribution board which has some sort of output buffering (like two entirely separate DC/DC converters) should give excellent isolation.Which makes it seem that noise reduction was your goal, or at least part of it. With the power distribution board you're still not getting any better than two separate batteries, but no worse either.
Simply put, I'm looking to power many things (with different input voltages) off one battery while not introducing an intolerable amount of electrical noise. Intolerable defined as impeding safe function, or resulting in damage.
 

HHaase

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Looking at that board, I see two discreet voltage regulator systems. Are the ESC outputs are regulated at all Or are they simply pass-thru for the battery voltage? I wonder what the outputs would look like on the scope for the regulated outputs.

A lot of stuff going on with that little board. Even connects the camera output to the transmitter input..... so FPV rocket!

-Hans
 

jqavins

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Simply put, I'm looking to power many things (with different input voltages) off one battery while not introducing an intolerable amount of electrical noise. Intolerable defined as impeding safe function, or resulting in damage.
And I pronounce your solution sound. :)
 
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Cl(VII)

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Looking at that board, I see two discreet voltage regulator systems. Are the ESC outputs are regulated at all Or are they simply pass-thru for the battery voltage? I wonder what the outputs would look like on the scope for the regulated outputs.

A lot of stuff going on with that little board. Even connects the camera output to the transmitter input..... so FPV rocket!

-Hans
Near as I can tell they are pass-thru. It is pretty unlikely that I will use those as there are four feed for 5V and/or 12V (one BEC each, and the video power pads).
 

HHaase

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Near as I can tell they are pass-thru. It is pretty unlikely that I will use those as there are four feed for 5V and/or 12V (one BEC each, and the video power pads).
Just make sure to measure the 12v output if you're using it, particularly with a 3S battery. Depending on the regulator they used it may not output the full 12v with less than a 4S.

-Hans
 

Cape Byron

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Joy in the mailbox. My LiPo batteries and charger arrived in the mail. Time to do some soldering...

Horizon Models WRESAT arrived to challenge my PMC skills. I'll unbox it after doing some more chores.

'Two-up' got a well deserved paint job to go with her stock nose cone. I'll ask the local Fire Brigade Captain for a burn permit next week. I have prototypes to test!

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OverTheTop

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I hear you, but part of what these boards are designed to do is minimize that interference in racing drones. Our stuff is pretty constant drain, especially compared to four drone motors. The exception would be on deployment charge firing, and that should be low current too with ematches unless there is a short. I'm doing this more in an effort to see how much I can cram into a small space than to reduce interference. I'm looking at it the other way, i.e. is the increased interference and loss of battery redundancy worth the space and wiring complexity savings in crammed electronics bays. When designing things to fit in 38mm rockets, the batteries are often the most frustrating part. I want to see if I can fit a camera, 2 altimeters and a tracker in one 38mm bay that is about 8" long...I think I can if this works, it will certainly be easier.

If nothing else it will be a cheap ($13) learning experience.


View attachment 446536 View attachment 446537
There are nice big pads on the periphery of that PCA, with grounds next to Vcc/5V/12V. One of the ways they save money in these things is to get away with the minimum number of capacitors. You can easily add some SMT caps across those conveniently placed pads. This will additionally decouple each supply from the source, as well as shunting any RF pickup on the leads (aka antennas) exiting the board. That should reduce any internal EMC problems greatly. I would think caps around 10u or 22u would be a reasonable guess. Note that typical ceramic capacitors of those values have dielectrics (like Y5V) that are highly voltage dependent. The higher the voltage the lower the capacitance. So a nominal 22u cap might end up more around 10u around the maximum working voltage. The two takeaways from this are; check the data sheet, and use a higher rated voltage to minimise this drop. If you use C0G or X7R capacitors this reduction is minimal or nil. In the capacitances needed these will not be available in those nice dielectrics.

Personally I would be adding capacitors to at least some of those locations. YMMV ;)
 

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