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What do you want in a timer?

Started by Tim Wescott, February 25, 2014, 01:22:49 PM

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Tim Wescott

Suddenly I'm working on not one, but two timer projects.

One's a teeny tiny timer for Larry Renger's program to put planes in the hands of kids.

The other is a project to make a timer that -- with the exception of size (it's big) -- can be all things to all people.  It's turning into a bit of a monster, but I think I'll get it done.  I'm modest, so I'm calling it Tim's Universal Timer.


  • What it definitely has:

    • Four connections for input or output, pulse or logic
    • A freaking insanely powerful processor for a mere timer (STM32F303)
    • A USB port (I said it's turning into a monster!)
    • The ability to talk to, and be programmed by, a JETIBox
    • A 3-axis gyro, 3-axis compass, and a 3-axis accelerometer
    • 2 megabytes of flash memory, for data-logging
    • A blinking light, because no board with a processor should be without one*
  • What it definitely will have:

    • The ability to emulate a KR timer or a Hubin timer
    • The ability to sequence landing gears along with motors
    • The ability to control more than one motor in a Renicle-esque way
    • The ability to sequence things other than motors, if that's what you want (consider a FF-style motor cutoff after six minutes)
    • The ability to detect premature motor or IC engine stall, and extend the landing gear**
    • The ability to detect one motor or IC engine cutting out prematurely, and cut out all the others
    • The ability to record RPM and all motion of the aircraft into flash, and upload it to your computer after a flight, for review
    • And more.  Read on
  • What it will probably have:

    • The ability to emulate Igor Burger's timer
    • The ability to regulate an IC engine speed***

The way that I'm achieving such flexibility, and a good part of the reason that this project has turned into a monster, is because in order to meet my minimum requirements, I needed to give the thing a programming language**** of its own.  This fact means that you'll be able to take a variety of modules -- RPM detectors, PID controllers, timeouts, and the like, and combine them in ways that I have not yet imagined.  Then you'll be able to download a program to the timer (remember the USB port?) and have it run the next time you turn it on.

So, given that you have an idea of what this critter can do -- what do you want in a timer?  Forget any constraints -- just say what you'd like a timer to do, and ignore anyone (even me) that says "oh, that's not possible*****".

* Well, almost none.  To quote a new customer of mine who's very power-consumption sensitive, and who will be potting his board in opaque epoxy: "What the hell is this light here for?"

** Or drop the landing gear immediately after a crash.  I suggest no retracts if you're still at the crashing stage.

*** Whether there's any advantage to it or not.  This kind of comes for free with the KR timer emulation.

**** Any time a software engineer for an embedded product waltzes into a design review and announces that he's working on a programming language for the product, the correct and rational response is for every other engineer in the room to turn to him as one, and say ARE YOU CRAZY!!!.  Then, as follow-up, they each need to collar the guy one by one and say "OK, explain to me why you're not crazy."

***** Except for teaching you how to pick up women in bars.  If I were born with the technical chops to make a gizmo that would help me pick up women in bars, I would still be single.  Or quite happily dead from exhaustion.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

John Cralley

Can you make it the size of a Hubin FM-9 and under $10???  VD~ VD~ VD~
John Cralley
Scratch Built - Often Re-kitted!!!
AMA 52183
Central Illinois

Tim Wescott

Quote from: John Cralley on February 25, 2014, 03:40:29 PM
Can you make it the size of a Hubin FM-9 and under $10???  VD~ VD~ VD~

The one I'm making for Larry has a target BOM cost of $5.00, which we may meet in quantities over 80.  The only thing standing in the way of it being the size of a Hubin timer is someone willing to volunteer to solder it up in surface mount, rather than through-hole -- and it'll get cheaper, because a big part of the BOM cost is the bare board.

How are you with 0402 resistors and SOT-23-6 packages?
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

steven yampolsky

Few ideas:
1) a mechanism to measure line tension. Imagine an active line tension control system that maintains constant line tension in all quatrants of the sphere.
2) a video camera or a plug for one. maybe several cameras. wireless video transmitter. Imagine being able to view the flight from multiple angles live on multiple monitors.
3) interface for wireless telemetry.Google Glass has made some big waves. Imagine being able to see telemetry in flight. It would be a boon for trimming.
4) bluetooth interface to program. Why use a programming box? I should be able to program it with my iPhone.
5) ability to define a multi-dimensional map for IC engines performance like in cars. the axis' would be fuel, air amount, barometric pressure, humidity.
6) bellcrank position or rate of deflection sensor. Imagine being able to predict engine power requirements as a maneuver begins.
7) relative altitude sensor. it would be great to know how high the model is off the ground. The training value of being able to see(wireless telemetry and google glass) where 5ft is tremendous.




Tim Wescott

Quote from: Steven Yampolsky on February 25, 2014, 06:56:39 PM
Few ideas:
1) a mechanism to measure line tension. Imagine an active line tension control system that maintains constant line tension in all quatrants of the sphere.

Anything that can generate a 1 to 2 millisecond pulse train can be registered, recorded, and maybe acted on.  I'm not sure if there's value in active line tension control, but if someone makes the gizmo, it should take little or no systems work to make it affect motor speed.

(This is why I was asking -- stuff out of left field, yea!)

Quote from: Steven Yampolsky on February 25, 2014, 06:56:39 PM
2) a video camera or a plug for one. maybe several cameras. wireless video transmitter. Imagine being able to view the flight from multiple angles live on multiple monitors.
3) interface for wireless telemetry.Google Glass has made some big waves. Imagine being able to see telemetry in flight. It would be a boon for trimming.

These can be bought for RC planes.  Top-o-the-line RC receivers these days transmit telemetry back.  So, buy one and shove in.  Ditto, the in-flight video stuff is a solved problem, used by the quad copter guys the world around.

Quote from: Steven Yampolsky on February 25, 2014, 06:56:39 PM
4) bluetooth interface to program. Why use a programming box? I should be able to program it with my iPhone.

With an appropriate USB cable you'll be able to talk to it with your iPhone.  Or, at least you can talk to an Android phone -- I'm not sure what apps are out there for iSpend phones.  Bluetooth is horrendously expensive for small production runs -- you either need to spend on the order of $100,000 on FCC compliance testing, or you buy a certified module that starts at about $45 a pop that takes up half a square inch of board space.

USB, on the other hand, takes up about 1/10th inch of board space on one side (leaving the other side free for other things), and less than $2.00 worth of parts in small quantities.

This board uses an FTDI FT230X USB to serial chip and will use a human-readable serial data stream; search on iPhone terminal apps that talk to that chip, and you've found an app to talk to the board.

Quote from: Steven Yampolsky on February 25, 2014, 06:56:39 PM
5) ability to define a multi-dimensional map for IC engines performance like in cars. the axis' would be fuel, air amount, barometric pressure, humidity.

Why?  I'm not challenging -- I'm curious.

Quote from: Steven Yampolsky on February 25, 2014, 06:56:39 PM
6) bellcrank position or rate of deflection sensor. Imagine being able to predict engine power requirements as a maneuver begins.


  • Cheap: gut a servo, leaving the output shaft and pot.  Replace the board and motor with a board that generates a 1-2ms pulse train (see my answer to your comment #1, above)
  • Spendy: Build a bellcrank sensor circuit ala Kim Doherty (http://stunthanger.com/smf/index.php?topic=32528.0) with that 1-2ms output

You don't have to stop there -- with a gyro on the board, it's conceivable that you could move the CG back and play with eletronic stability enhancements.  I have no freaking clue if the plane would fly better as a result, but you could do it.

Quote from: Steven Yampolsky on February 25, 2014, 06:56:39 PM
7) relative altitude sensor. it would be great to know how high the model is off the ground. The training value of being able to see(wireless telemetry and google glass) where 5ft is tremendous.

Maybe next year.  In theory, with gyro and accelerometer information you could deduce this.  In reality (thank you, Howard Rush, for bursting my bubble) the available chip-scale sensors aren't up to the task, and a sensor suite that could do the job would probably weigh a pound.

You may be able to use sonic ranging over pavement, I dunno.  I don't think radar altimeters work well at five feet.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Mike Keville

Too much electronic/radio crap invading Controline.  Stop it!
FORMER member, "Academy of Multi-rotors & ARFs".

Mike Anderson

Quote from: Mike Keville on February 25, 2014, 09:38:59 PM
Too much electronic/radio crap invading Controline.  Stop it!


Your opinion is noted, and of course will be ignored.    ;D
Mike@   AMA 10086
Central Iowa

Tim Wescott

Quote from: Mike Anderson on February 25, 2014, 09:59:55 PM
Your opinion is noted, and of course will be ignored.    ;D

Please don't turn this into a flame war.  What Mike wants in a timer is a spring, some gears, and a lever or two.  I can accept that.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Mike Anderson

No flame intended -- just a gentle poke and a smile.
Mike@   AMA 10086
Central Iowa

Howard Rush

Quote from: Steven Yampolsky on February 25, 2014, 06:56:39 PM
Few ideas:
1) a mechanism to measure line tension. Imagine an active line tension control system that maintains constant line tension in all quatrants of the sphere.
2) a video camera or a plug for one. maybe several cameras. wireless video transmitter. Imagine being able to view the flight from multiple angles live on multiple monitors.
3) interface for wireless telemetry.Google Glass has made some big waves. Imagine being able to see telemetry in flight. It would be a boon for trimming.
4) bluetooth interface to program. Why use a programming box? I should be able to program it with my iPhone.
5) ability to define a multi-dimensional map for IC engines performance like in cars. the axis' would be fuel, air amount, barometric pressure, humidity.
6) bellcrank position or rate of deflection sensor. Imagine being able to predict engine power requirements as a maneuver begins.
7) relative altitude sensor. it would be great to know how high the model is off the ground. The training value of being able to see(wireless telemetry and google glass) where 5ft is tremendous.

8) MP3 player.  I think any digital electronic device is required by law to have one.
The Jive Combat Team
Making combat and stunt great again

Phil Krankowski

Make it blue tooth to my phone for easy programming!

(I think I am kidding, but that would be awesome)

OK, on a more serious note, make it so it can talk to and power a USB blue tooth adapter

http://www.newegg.com/Network-Bluetooth/SubCategory/ID-295?Tpk=usb%20bluetooth

bootstrap off someone else's hard work.

USB to an android app would work too, quite well in fact, for me.

Phil

Steve Helmick

Smoke deployment technology would be swell.  VD~ Steve
"The United States has become a place where professional athletes and entertainers are mistaken for people of importance." - Robert Heinlein

In 1944 18-20 year old's stormed beaches, and parachuted behind enemy lines to almost certain death.  In 2015 18-20 year old's need safe zones so people don't hurt their feelings.

Tim Wescott

Quote from: Howard Rush on February 26, 2014, 02:29:17 AM
8) MP3 player.  I think any digital electronic device is required by law to have one.

I can do that.  It may set the initial delivery date beyond August, though.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Tim Wescott

Quote from: Steve Helmick on February 28, 2014, 10:01:50 PM
Smoke deployment technology would be swell.  VD~ Steve

Can do!  Add a servo and one of these: http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXZ674&P=7.  Do you wish for it to only come on when the airplane is inverted, or in maneuvers?  That can probably be done, too, but not in the initial revision.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Mark Scarborough

Quote from: Tim Wescott on February 28, 2014, 10:54:59 PM
Can do!  Add a servo and one of these: http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXZ674&P=7.  Do you wish for it to only come on when the airplane is inverted, or in maneuvers?  That can probably be done, too, but not in the initial revision.
Probably only as it passes the judges,, you know with a hint of castor ,, perhaps a rpm sensing sound generator to create the nice burble of a ST 60 in stunt mode to go along with it,,
For years the rat race had me going around in circles, Now I do it for fun!
EXILED IN PULLMAN WA
AMA 842137

Tim Wescott

Quote from: Mark Scarborough on March 01, 2014, 11:53:10 AM
Probably only as it passes the judges,, you know with a hint of castor ,, perhaps a rpm sensing sound generator to create the nice burble of a ST 60 in stunt mode to go along with it,,

It was Steve asking, and I know he flies IC, so I just figgured he wanted smoke on HIS plane.

Someone needs to build a smoke system for electrics.  It just needs to happen.  I'm not so sure about the ST 60 burble, though -- when I make the version with Howard's MP3 player you could hook it up to a loudspeaker, but that may take some time.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Tim Wescott

I left out one of the features -- you'll be able to clone programs and save them with individual settings.

That means that instead of having to remember how you program for wind or calm or cold or whatever, you can have a program called "normal", one called "windy", etc.

I dunno how much value there'll be in that, but the option will be there.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Tim Wescott

On cloning programs, and on downloading custom programs:

What's the maximum number of programs that you could see wanting on one timer?  I can't imagine needing more than four -- one custom program as it was downloaded, then three others that have been tweaked for different conditions.

I'm struggling with how to manage flash memory, and I think I'm going to go for "space-wasteful but easy".
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

steven yampolsky

Here's the fundamental problem that I see with electronic setups. Every function requires a new box/board to wire up.

You want retracts? That's a box.
You want telemetry? that's another box.
You want to control your motor? That's another box.
You want to control your motor based on G forces? Yet another box
You want video? that's another box!

And EVERYTHING has to be wired up!
And to adjust anything, I need yet ANOTHER box!

Nightmare!

A single platform with plug-n-play expandability is what we need! Basic functions such as engine speed control and timer would be core to the board but everything else would be a module one can plug in. All adjustments would be via a PC/Android/iPhone type of device.


Tim Wescott

Quote from: Steven Yampolsky on March 03, 2014, 06:45:45 AM
Here's the fundamental problem that I see with electronic setups. Every function requires a new box/board to wire up.

You want retracts? That's a box.
You want telemetry? that's another box.
You want to control your motor? That's another box.
You want to control your motor based on G forces? Yet another box
You want video? that's another box!

And EVERYTHING has to be wired up!
And to adjust anything, I need yet ANOTHER box!

Nightmare!

A single platform with plug-n-play expandability is what we need! Basic functions such as engine speed control and timer would be core to the board but everything else would be a module one can plug in. All adjustments would be via a PC/Android/iPhone type of device.

I can see your frustration, but how much money do you want to shell out, and how long do you want to wait for product?  Developing stuff like this takes time which could be spent doing other lucrative things.  So a serious businessman does a very basic cost/benefit analysis, that pretty much works by figuring out how much it'll cost to develop the gizmo, then working out how many units he'll need to sell to make a good profit, then looking at the market and seeing if it has the capacity to buy that many units.  Now comes our problem: as a market, we're teeny.  We just don't have leverage.  Anyone who's approaching this as a serious businessman can do a cost-benefit study in their head and come up with "no", without ever needing to grab a pencil and a used envelope.

For instance, I've already put enough time into this that I would need to sell about 1000 timers at a pretty steep markup just to pay for my time so far -- and I ain't done by a long shot, and I ain't expecting to sell 1000 timers at all, much less at a price enough above the materials cost to pay me for my work.  So I'm already throwing my time into the wind on this one: I'm doing it because I want to do it.

Changing the subject a bit, I'm really not understanding why you want to lump video in with everything else -- a video system doesn't need to talk to the flight control system, or visa versa, so I'm not sure how you expect the overall system behavior to be enhanced with video.

If you put video aside, and you don't mind a 10-minute lag in your "telemetry" (who can look at telemetry while they're flying anyway?), then I'm pretty much poised to deliver everything you want.  So why are you still unhappy?
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Mark Scarborough

The thing is,, all this stuff would seriously handicap a competition airframe with weight and complexity,, so if its not for a competition airplane, all that stuff is pretty much available in the RC world,, why reinvent the wheel,,
For years the rat race had me going around in circles, Now I do it for fun!
EXILED IN PULLMAN WA
AMA 842137

Tim Wescott

Quote from: Mark Scarborough on March 03, 2014, 10:09:43 AM
The thing is,, all this stuff would seriously handicap a competition airframe with weight and complexity,, so if its not for a competition airplane, all that stuff is pretty much available in the RC world,, why reinvent the wheel,,

Video and telemetry, certainly, although they may make a good coaching aid, particularly self-coaching.

Retracts -- probably.  People keep trying them because they're so kewl, but if their advantages outweighed their disadvantages I think you'd see them a lot more on the top guys' planes.

Control your motor?  I read that as a timer and ESC, and that's required if you're going to fly electric.  Ditto control your motor from G-forces -- that's a different timer with a (possibly) different ESC, but it's not a severe weight or structural penalty over a Hubin or KR timer.

I haven't weighed it yet, but the timer that I have in mind is probably going to come in at about 3/4 ounce.  That's more than the existing timers, but it comes with data logging.  If people seem to want 1/4 ounce less weight and no data logging, that can be arranged.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Mark Scarborough

I see your target Tim,, its admirable,, and I do see advantages, but the telemetry and FPV just dont make sense to me,  but then,, I am just me,

For years the rat race had me going around in circles, Now I do it for fun!
EXILED IN PULLMAN WA
AMA 842137

Leo Mehl

Quote from: Mike Keville on February 25, 2014, 09:38:59 PM
Too much electronic/radio crap invading Controline.  Stop it!

Come on Mike . It is better to embrace new tecnolegy rather than not ecnowlege that its there. All new tecknoledgy makes our life better. electric fo me has made the fact that I don't need to trim the needle valve or even get closs to the prop and I don't have to do a lot of engine trimming on am new plane. I think all of this has maden it5 better for me!

Leo Mehl

Quote from: Mark Scarborough on March 01, 2014, 11:53:10 AM
Probably only as it passes the judges,, you know with a hint of castor ,, perhaps a rpm sensing sound generator to create the nice burble of a ST 60 in stunt mode to go along with it,,
I love the fact that you can here what the flyer says as he screws up the stunt.!


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