USB card adapters crash Pi4

Nope. I've never even heard of cameras on Free flight. They're just irrelevant because by definition the only control possible on a free flight model is an RDT: the whole point is that the model can't be controlled after launch because what a contest is about is the art of launching into lift and of designing/building trimming the model so it ca self-centre in the lift patch it was launched into. Scoring is simple: at the end of a competition the winner is the person with the highest total flight time.

RDT = radio dethermaliser - pushing the button is an irreversable action that overrides the onboard timer forcing it to end the flight.

We do carry reverse links though (radio trackers to aid retrieval after a flight and some carry a GPS which modulates the tracker to send location information back to the model's flyer. Like the tracker, this just makes retrieval easier after the flight.

Seems like you might never have seen a free flight model. Look here:

and there'a bit on the Koster timer here:

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Martin    | martin at 
Gregorie  | gregorie dot org

It's the default setup, using UUID. The machine was already running, so that shouldn't matter. Plugging in the adapter seemed to cause a persistent USB error, it was the persistence that seemed most odd. There's no powered hub involved, on the thesis that a 3.5 amp power supply and a USB 3.0 port should be ok on their own. Indeed, the machine boots hands-off from the mechanical hard disk.

I did do a power supply check. It's not quite as good as expected,

5.08 volts booted and idle, 5.00 to 5.03 volts between GPIO pins 2 and 39 while running the "SD card speed test" which appears to be a "boot device speed test" instead. That seems good enough to support a USB-microSD adapter being plugged in. Of course, a DVM is blind to transients, so it's of limited use.

I'll wait until I don't mind crashing the machine and try again using the USB 2.0 ports.

Thanks for writing,

bob prohaska

On a sunny day (Sat, 2 Jan 2021 20:41:05 -0000 (UTC)) it happened Martin Gregorie wrote in :

I have no experience with 'free flight' other than folding paper airplanes.... Cameras weight next to nothing and can record automatically to some microSDcard... would be nice to get an aerial view?

Yes,

Nice, but being an electronics freak so to speak I want power and control.

But free flight models seem a great way to learn about aerodynamics. Not much of a competition person here, just experimenting. make my own rules set my own targets.

Nice, for those days electronics, used the 555 myself in industry...

These days I just program a Microchip PIC controller in asm, set values via serial link before takeoff, like for the air text:

HUD display with on screen GPS and power:

Auto pilot controlling drone and dropping load:

I do not use a solenoid, but an electric motor with a screw that releases some nuts, this gives more power with heavy loads, at low peak current.

also note the micro-sdcard for the video...

Precise hands free flight to a few cm. Better get the GPS stuff right, the first experiments needed fast user interaction to prevent it flying through windows etc... The 'tronics' is basically very simple. Programming in asm on PIC micros is fun :-) It (the hardware) does what you tell it to do,

China has demonstrated large groups of drones flying art like formations using something like this tech:

Seems unlikely. There's a whole 'shanzhai' ecosystem of product development in Shenzhen, churning out rapid iterations of products all riffing off/stealing from each other:

(separately, the fact that this listing is out of stock is just an Amazon artifact. You can likely find the same product elsewhere under a different brand. Amazon encourages sellers to have multiple bogus brands, but you'll probably find it unbranded on ebay and Aliexpress too)

Theo

Understood, but as far as models are concerned, I preferred flying control-line models to RC. For controlled flight I just climb into my Standard Libelle and take a winch launch: just 35 seconds from first movement to 450m and cruises at 120 kph.

Yes, that's very true. But, a big benefit of competition flying is that it gets you out of the house on less than perfect days: no matter how good or bad, the weather is the same for everybody in the contest.

Yes, that makes sense.

I've got a PICAXE to experiment with, which I quite like apart from its rather unpleasant unsigned integer BASIC, but I csan live with that. I do like the built-in device controllers though, especially the servo drivers

- perfect for controlling small BEC-equipped motors and EDF (electric ducted fan) systems.

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Martin    | martin at 
Gregorie  | gregorie dot org

On a sunny day (Sun, 3 Jan 2021 14:39:08 -0000 (UTC)) it happened Martin Gregorie wrote in :

Yea I better not go into detail here of my adventures in the F100 Super Sabre.. when I got the order to abort, so many lives at stake... ;-)

Yes, one problem here is that the government decreed the whole area to a no fly zone for model aircraft.. I am close to Leeuwarden mil airbase. One reason I do not fly this one:

serves more as ornament, wrote a whole lot of stuff for that though. But it needs space, 160 km/h.

I also wrote the software I use to program the PICs, the hardware is based on the noppp programmer, just modified it a bit for the modern PICs:

uses PC parport, using a PCI card with parport connector in the modern PC..

did many PIC projects, some are on my site:

As to that BASIC: in my view asm is often simpler, indeed the PIC hardware is nice. I use an asm math library written by someone else, so far 32 bit integer was all I needed, In asm you do not have to worry about code generation by whatever... compiler ...

Also the PICs give you near zero boot time, near zero power consumption, near zero weight, near zero cost (about 2$ a piece).

"If you need to use floating-point arithmetic in FORTH, you do not fully understand your application"

Not sure if it was Charles Moore or Leo Brodie who said that.

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Joe

Dozens of them:

Theo

It makes sense, though, depending on your applications. In 50 years of commercial programming, I can count the number of times I've used floating point on the fingers of one hand.

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PICAXE BASIC is a little more limited than that: variables may be 8 or 16 bit and they are all UNSIGNED, which, I would suggest is a bit more limiting than doing without floating point. This is the only computer language I've used that doesn't support signed integer values.

A fairly rapid web search failed to discover whether unsigned arithmetic is a feature of the BASIC or if the PIC micro-controller only works with unsigned values. I found several low level architecture descriptions, which all mention stuff like data storage and register lengths, but since none of them mentioned signed arithmetic, it seems that it isn't supported.

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Martin    | martin at 
Gregorie  | gregorie dot org

There is no feature list of BASIC. There are standard BASICs from Dartmouth, there was Applesoft on the Apple II (integer only), and most BBC BASICs were only distinguishable from PASCAL by having built-in assemblers (yes, including BBC BASIC V on the ARM-based Archimedes). Quite a variation. I hated the old line number thing.

No. All the arithmetic operators are signed, at least in the less primitive PICs. They only work with the PIC data word length, but can be easily cascaded for more bits using the accumulator status bits. Look at the instruction set in any PIC datasheet.

I've only ever used assembler, as I've wanted complete control over timings, and I don't think I've ever needed more than 16 bits. I've done mostly TV camera remote control software and a Canon lens controller. There are C compilers for the PICs, but I wanted to write my own interrupt routines, as the SPI used on the Canon AF can be pretty fast, and the Canon SPI variation meant some real-time bit banging was required.

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Joe

I know that all so-called BASICs differ, some radically from the original Dartmouth BASIC. I thought that the context would make it plain that I was talking about PICAXE BASIC, which differs enough from traditional BASICs to be given another name (labels not numbers for branch destinations and subroutines, long names for variables, named constants, unsigned arithmetic and comparisons, conditional statement inclusion).

Not according to the current PICAXE BASIC manual, which gives numeric ranges for 8 and 16 bit variables capable of containing byte values in the range 0-255 and explicitly says that byte values are unsigned. It alao says that 16 bit variable can hold 0-65535, which implies, though it doesn't state, that these are unsigned.

See

If this is a mistake, they get a down vote for not correcting their manual, despite having three years to have made the correction - I bought the PICAXE and downloaded to manual 2.5 years ago and then got distracted from that project, but the online manual's wording (section 2, page 13) remains the same - I just checked.

BTW I'm using the PICAXE-14M because I need at least 3 PWM outputs. and, to put this on topic for the RPi group, am running the BASIC compiler/ uploader on a headless Pi 2B. This setup successfully uploads compiled code to the PICAXE and displays messages from it on the RPi's console.

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Martin    | martin at 
Gregorie  | gregorie dot org

On Sun, 3 Jan 2021 22:40:33 -0000 (UTC), Martin Gregorie declaimed the following:

PICAXE BASIC and BASIC-Stamp BASICs were optimized for microcontrollers with GPIO. Unsigned arithmetic maps to an 8-bit GPIO control register quite well (especially for bit masking). The processor chips have most of their flash memory filled with a simplified BASIC byte-code interpreter -- one's application gets downloaded (as byte-code) to a small EEPROM (or worse -- a large RAM) and is treated as data by the interpreter.

A BS2 has only 32-bytes of RAM, and 6 of those are dedicated to GPIO input, output, and direction control. That leaves just 13 16-bit variables or 26 8-bit variables. The BS2 does allow defining variables and bit, nybble, byte, or word -- and the compiler does its best to optimize the RAM allocation. The manual does imply that the BS2 supports signed 16-bit values -- but when outputting them (debug print) one needs to specify the SDEC formatter, otherwise one gets an unsigned representation.

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	wlfraed@ix.netcom.com    http://wlfraed.microdiversity.freeddns.org/

Odd. I use it extensively. Not for money oriented stuff tho

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Sorry, misunderstanding. I thought you were asking if PICAXE couldn't do signed because the underlying PIC processor couldn't handle signed.

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Joe

Not that odd: in a 30 year IT career (system design, programming, sysadmin, much of it databases and finance-related systems) I can only think of one survey analysis program I wrote, in Algol 60, that used floating point (and that was for a one-off task).

Financial systems never use floating point for accuracy reasons: consequently integers are used to hold currency amounts: sterling amounts are held as pence, euros and dollars as cents and the equivalent convention is used for all other currencies. The only exception I'm aware of was financial packages written in BASIC for early microcomputers, and that was only because (a) integers tended to be 16 bits at most and (b) their PRINT statements often couldn't interpolate a decimal point when displaying an integer value.

OTOH COBOL was designed from the outset to deal with currency amounts held as integers:

might look as if its floating point but, the variable would be a 32 bit signed integer which would be read or written as a string containing the currency sign, possibly containing comma separators and with a decimal point separating pounds from pence.

RPG (UGH!) does the same and all modern languages (and assemblers) have sufficiently powerful number scanning and formatting library functions to do the same.

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Martin    | martin at 
Gregorie  | gregorie dot org

microcontrollers

GPIO

Agreed - I've done rather more with BS2 STAMPS than I have with PICAXE - even had a flight timer for an F1A glider running on a breadboard. This read timer settings, which are all positive values, from a control box, but didn't need to output them. The logic did use signed values, though, to terminate count-down sequences.

However, I barely got past noddy experiments to get familiarised with PICAXE BASIC before putting that project to one side, but its likely to be woken up again quite soon.

So, I'm aware that the BS2 BASIC uses signed integer variables and consequently was quite surprised that PICAXE BASIC doesn't.

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Martin    | martin at 
Gregorie  | gregorie dot org

No problem. At least this made me look at the PIC architecture and discover that it doesn't handle signed integers - I think its the only system I've know of at that doesn't, so I didn't realise at first that this limitation is in the hardware rather than a feature of the BASIC compiler.

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Martin    | martin at 
Gregorie  | gregorie dot org

I gather that micro-cents/pence are sometimes used when interest calculations are involved and the fractions matter, I've used milli-pence.

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