Author Topic: CHEAP 1/2A idea (Read 2963 times)

Tom Vieira · « **on:** April 04, 2019, 10:24:32 AM »

Hi guys,

looking for help here. if you check out my thread in the general forum "key to getting youngsters involved", I think e-power might be the trick after talking with my nephew.

I'm thinking 1/2a sized, with simple CHEAP can motors, and the little 2s batteries the micro park flyers use. ALL of this is in terms of keeping it stupidly simple, and as CHEAP as possible. I found this esc at hobby king

https://hobbyking.com/en_us/turnigy-20a-brushed-esc.html?countrycode=US&gclid=EAIaIQobChMI4fLugN-24QIVFM-yCh0OgwtWEAQYAiABEgI0ivD_BwE&gclsrc=aw.ds

could a simple 555 timer circuit be used to drive an esc? I'd prefer even just being able to drive the motor at full line voltage for a given amount of time, but I'm not exactly an electrical engineer, I'm not too sure on how to design boards to act as a voltage cutoff. I've only assembled a few board kits for my model rockets and dew heaters for telescopes.

think along the lines of a Sig dewey bird here. bare bones, anyone with a bottle of glue and a piece of sandpaper can throw together. and most importantly CHEAP and EASY to repair. I wouldn't even be against using foam poster board over balsa. the kind of thing that'd take an hour to put together tops, and even possibly be used for some sort of outreach event. We do events like that with my rocketry club, and they are always a "blast" so to say. ideally hit an all set ready to get in the air price point of $50 or (hopefully) less. don't worry about factoring in labor hours. total material cost of $50 or less (including finishing supplies).

See where I'm going with this?

john e. holliday · « **Reply #1 on:** April 04, 2019, 12:37:56 PM »

Where is Dennis A, I think he could do it.

Tom Vieira · « **Reply #2 on:** April 04, 2019, 01:31:33 PM »

I just talked with one of my electrical engineer buddy's here at work. he sounds stoked by this idea!

he's a robot hobbyist at home, so knows exactly what I'm going for on this. I've almost gotten him to take the plunge in to CL a couple of times.

John Rist · « **Reply #3 on:** April 04, 2019, 04:29:39 PM »

Quote from: T.J. Vieira on April 04, 2019, 10:24:32 AM

Hi guys,

looking for help here. if you check out my thread in the general forum "key to getting youngsters involved", I think e-power might be the trick after talking with my nephew.

I'm thinking 1/2a sized, with simple CHEAP can motors, and the little 2s batteries the micro park flyers use. ALL of this is in terms of keeping it stupidly simple, and as CHEAP as possible. I found this esc at hobby king

https://hobbyking.com/en_us/turnigy-20a-brushed-esc.html?countrycode=US&gclid=EAIaIQobChMI4fLugN-24QIVFM-yCh0OgwtWEAQYAiABEgI0ivD_BwE&gclsrc=aw.ds

could a simple 555 timer circuit be used to drive an esc? I'd prefer even just being able to drive the motor at full line voltage for a given amount of time, but I'm not exactly an electrical engineer, I'm not too sure on how to design boards to act as a voltage cutoff. I've only assembled a few board kits for my model rockets and dew heaters for telescopes.

think along the lines of a Sig dewey bird here. bare bones, anyone with a bottle of glue and a piece of sandpaper can throw together. and most importantly CHEAP and EASY to repair. I wouldn't even be against using foam poster board over balsa. the kind of thing that'd take an hour to put together tops, and even possibly be used for some sort of outreach event. We do events like that with my rocketry club, and they are always a "blast" so to say. ideally hit an all set ready to get in the air price point of $50 or (hopefully) less. don't worry about factoring in labor hours. total material cost of $50 or less (including finishing supplies).

See where I'm going with this?

The speed controller above is for a brushed motor. If I were doing this I would go with a brushless setup. Looking at hobbyking they have many cheep components in the 1/2a size brushless realm. Might be a fun project to research. build. test fly and then report results on this BB,

Tim Wescott · « **Reply #4 on:** April 04, 2019, 06:40:42 PM »

You'd need something marginally fancier than a 555 timer, because most ESCs want to see you start at low throttle, then go high. That's both to provide calibration for "off", and as a safety in the case of an RC pilot turning his plane on with the throttle off of idle (turning on your monster with the throttle high is -- bad).

By the time you've got more than one chip on the board, you've exceeded the chip count and expense of a board with a cheap microprocessor on it.

Tom Vieira · « **Reply #5 on:** April 05, 2019, 05:48:15 AM »

understood that it's for a brushed motor. the idea is cost suppression. the model isn't meant to perform much more than takeoff and level flight.

Dennis Adamisin · « **Reply #6 on:** April 05, 2019, 07:18:58 AM »

Quote from: john e. holliday on April 04, 2019, 12:37:56 PM

Where is Dennis A, I think he could do it.

Doc - THANKS for the vote of confidence!

First off I think TJ is "on fire" with his idea & concept.

We live in a world of $300 sneakers & $1500 cell phones. While it is natural to go for the low cost set-up, I am not sure that cost should be the single overriding factor.

This weekend I will be building a Flite Streak trainer with a flexible motor mount.
* It will use a largish motor with a 5mm shaft. That combo will be far more robust than a small motor with a 2mm or 3mm shaft
* It will us a lefty prop; good for take-offs & line tension but most important a prop strike will simply unscrew the prop.
* It will use a flexible motor mount that should help disperse some crash energy.
* Brodak has a Hubin timer for FF that has a throttle setting and flight duration of 10-73 seconds. Some folks have had success with this indoors in a church auditorium training a Scout Troop. Since the timer essentially takes the place of an RC receiver, I think it should work with just about any type of brushed or brushless ESC.
* The battery box will allow a small battery with foam rubber around it, or a large battery with no foam but capable of multiple flights on a charge.
* The larger airplane will fly better than the small trainers. and be more robust to weather conditions. The system I am using will be throttleable enough to fly it anywhere from 42' - 70' lines, but I'd bet 52's will be the sweet spot. Still a school yard but not a back yard or indoors.
* The kit shows a 2" bellcrank, but I will use either a 3" or 4" and a long control horn to slow the controls way down.

I seem to recall that Larry Renger and the Knights worked out a "crowd trainer" that was a pusher, made of reclaimed political signs, using brushed motors. Virtually crash-proof. The combo was probably a good starting point for what TJ is talking about.

Tom Vieira · « **Reply #7 on:** April 05, 2019, 07:57:06 AM »

hey dennis! I like that prop rotation and flexy mount idea!

I know what you mean, some of the things parent's are willing to spend money on is absolutely nuts. no WAY would a kid be getting a $1000 phone in my house.

on those same lines, also goes my ideas. for some reason, people are willing to spend stupid amounts on "stylish" things, but not so much on things that actually teach life skills. considering it's a model, and it'd need to be built, I have a feeling many parents would be like "yeah, no.... not spending money on something that's not even ready to go". So, the idea of having everything in the box and ready to go is what I'm going after, and easy enough to assemble w/ directions clear enough that just about anyone could do it is what I'm going for. once I get my prototype built, I'm going to make another "kit" and give it to my girlfriend to build first, and get her input (she's awesome at writing procedural documents, a byproduct of being a government employee). then another for my niece or nephew to build solo (10 and 11 years old), get their feedback.

from there, beta testing (maybe send it to school with them to fool around with or around the neighborhood).....

this entire thing has got to be something a kid of say, 10 years old, can make the decision on himself to save his pennies and reach a target of savings quickly. I feel like I may be fighting a one man regional battle, but some of the words of encouragement I'm getting from you guys is helpful! AMA or industry isn't really going to help our cause, it's up to us. and I'm not a huge fan of complaining without putting effort in to it first! you hear a mess of "it'll never work" comments and the such with new ideas, but, at least we can say we tried!

John Rist · « **Reply #8 on:** April 05, 2019, 11:33:51 AM »

Quote from: T.J. Vieira on April 05, 2019, 07:57:06 AM

hey dennis! I like that prop rotation and flexy mount idea!

I know what you mean, some of the things parent's are willing to spend money on is absolutely nuts. no WAY would a kid be getting a $1000 phone in my house.

on those same lines, also goes my ideas. for some reason, people are willing to spend stupid amounts on "stylish" things, but not so much on things that actually teach life skills. considering it's a model, and it'd need to be built, I have a feeling many parents would be like "yeah, no.... not spending money on something that's not even ready to go". So, the idea of having everything in the box and ready to go is what I'm going after, and easy enough to assemble w/ directions clear enough that just about anyone could do it is what I'm going for. once I get my prototype built, I'm going to make another "kit" and give it to my girlfriend to build first, and get her input (she's awesome at writing procedural documents, a byproduct of being a government employee). then another for my niece or nephew to build solo (10 and 11 years old), get their feedback.

from there, beta testing (maybe send it to school with them to fool around with or around the neighborhood).....

this entire thing has got to be something a kid of say, 10 years old, can make the decision on himself to save his pennies and reach a target of savings quickly. I feel like I may be fighting a one man regional battle, but some of the words of encouragement I'm getting from you guys is helpful! AMA or industry isn't really going to help our cause, it's up to us. and I'm not a huge fan of complaining without putting effort in to it first! you hear a mess of "it'll never work" comments and the such with new ideas, but, at least we can say we tried!

When you get it under way I would be willing to kick in some bucks for one of the early kits to build and evaluate. Lord knows I have plenty of time on my hands to invest in such a project. Also we have several junior members in our club that could be test pilots. One more thought it should be able to do a simple loop. Kids learn fast and get bored easily.

Tom Vieira · « **Reply #9 on:** April 05, 2019, 11:40:52 AM »

very true. i'll work on it. like I've been saying, price is my driving factor, and I'd like to have everything but building supplies in the box, ready to go. they just need to supply the sandpaper, a knife, and glue.

Tom Vieira · « **Reply #10 on:** April 05, 2019, 01:12:09 PM »

ok, going off Bob's idea here for a semi schoolyard beef settling kinda combat capable thing....

still a simple build, but, i'm caving and looking at brushless......

https://hobbyking.com/en_us/turnigy-aerodrive-sk3-2822-1275-brushless-outrunner-with-short-shaft.html

what say you?

CircuitFlyer · « **Reply #11 on:** April 05, 2019, 05:29:33 PM »

Expanding on Tim's reply above. Here is one suggestion:

https://www.adafruit.com/product/3500

There are plenty more micro-controller development boards out there to choose from. Ask your electrical engineer/robotics hobbyist if he could write an Arduino sketch for a simple CL timer. You would still need to add some buttons, switches, wire and connectors to make it complete. It should still end up in your price range. If the kid gives up on control line at least he has an Arduino board to use for his next school project.

Paul

John Rist · « **Reply #12 on:** April 06, 2019, 12:38:31 AM »

Quote from: T.J. Vieira on April 05, 2019, 11:40:52 AM

very true. i'll work on it. like I've been saying, price is my driving factor, and I'd like to have everything but building supplies in the box, ready to go. they just need to supply the sandpaper, a knife, and glue.

Are we also talking battery and battery charger as well as air-frame and motor?

Tom Vieira · « **Reply #13 on:** April 08, 2019, 06:03:32 AM »

john, yup. hobbyking has a charger that's 110/12v that'll do 32s for 10 buck or so.

ultimately, it'll be an "open source" thing (at least as I envision it" a complete BOM w/part numbers and a "have at it" idea. but at first, try to make a few kits for distribution to interested parties. I'd be completely eating labor costs. this idea isn't about making money.

john e. holliday · « **Reply #14 on:** April 08, 2019, 09:42:15 AM »

I think I stated this in the past but, I think the late Jim Walker said the Firebaby's were give away planes. The profits came from the engine and Fire Cat.

John Rist · « **Reply #15 on:** April 08, 2019, 01:41:37 PM »

This is a possible cheep setup.
Controller: a servo tester. https://www.ebay.com/itm/NEW-3CH-ESC-Servo-Tester-CCPM-Consistency-Master-Checker-Tester-I/280875012283?hash=item41657490bb:g:o3oAAOxyd5tRy67f $1.12

This could be mounted on the airplane to drive the speed controller. when you plug up the battery you would have the tester knob set to off (or minimum). Then by turning the knob you could bring the motor up to speed. The problem is these tester's have 3 modes. Hopefully they come up in the manual mode or they remember the last setting. Could remove case to save weight.

Speed controller: https://hobbyking.com/en_us/turnigy-plush-10amp-9gram-speed-controller.html 10 amp with BEC. $13.07 it will provide power to the servo tester. It will also turn off when the battery gets low. With this setup you will not be able to control flight time. Once you launch its go till the battery is used up. A small battery should give reasonable flight times.

Motor: https://hobbyking.com/en_us/turnigy-2211-brushless-indoor-motor-2300kv.html. 2211 KV brushelles motor. $12.46 I think this would be in the 1/2A range. It should turn a 6x3 prop at 20K rpm.

Prop: https://hobbyking.com/en_us/turnigy-2211-brushless-indoor-motor-2300kv.html $2.97 for six props.

Battery: https://hobbyking.com/en_us/turnigy-nano-tech-370mah-3s-25-40c-lipo-pack.html $6.20. A little math and it looks like it should run for about 3 to 4 minutes if the current draw is around 6-7 amps. I guessing closer to the 3 minutes because the speed controller will cut off when it has used 80% of the charge.

This all all adds up to $38.82 plus shipping. And does not include a battery charger. This of course pushes the $50 limit. But the valid ideal in all this it to use a servo tester as a timer. Its advantage is cost. $1.12. It is basically the 555 timer discussed before. The disadvantage is that time is not settable. Once you launch you go till it runs out of juice, Just like a gasser. However you can't short load the tank.

Tom Vieira · « **Reply #16 on:** April 09, 2019, 05:51:24 AM »

i like the servo driver idea, hadn't thought of that! still need a way to protect the battery.... hmmm....

John Hammonds · « **Reply #17 on:** April 09, 2019, 11:06:18 AM »

Quote from: T.J. Vieira on April 09, 2019, 05:51:24 AM

i like the servo driver idea, hadn't thought of that! still need a way to protect the battery.... hmmm....

Would electric RC car packs have more impact protection? I seems to remember from my car racing days (Long time ago using Nicads) there were some pretty hefty shunts.

Alternatively A123 style Lion packs are a lot more damage resistant then Lipos. I used them when I got back into CL several years ago. Only ever destroyed 1 cell from a pack which was only because it broke loose after a figure 9 and the cell casing was worn away by the still spinning motor case. I guess weight isn't too much of a consideration here?

TTFN
John.

Tom Vieira · « **Reply #18 on:** April 09, 2019, 01:15:11 PM »

it wasn't impact protection an over draining them that i am concerned about.

John Rist · « **Reply #19 on:** April 09, 2019, 06:46:46 PM »

Quote from: T.J. Vieira on April 09, 2019, 01:15:11 PM

it wasn't impact protection an over draining them that i am concerned about.

Any good speed controller will do this. Almost all ESC are designed for RC aircraft use. Most of then go to low motor when battery is low and go to cutoff when at 80 to 90% use. That's why I suggested the Trunigy plush series. By the way the program card is like $8 https://hobbyking.com/en_us/turnigy-besc-programming-card.html It's not absolutely necessary but I have one because all I use are Trunigy Plush controllers. They work well with my KR timers. I would have to check but I think you have some programmable choices as to how a Trunigy plush handles low voltage motor cut off. If you were selling turn key kits you could have a program card and program the speed controllers before you ship.

Tom Vieira · « **Reply #20 on:** April 10, 2019, 05:55:14 AM »

John,

good point!

However, i think i have the timer situation figured out. i'll need to build my own, but i think i can get it set for variable motor control and selectable flight time for pretty cheap....

Tom Vieira · « **Reply #21 on:** April 18, 2019, 09:19:01 AM »

So, Bob Heywood is one of my partners in crime on this, and tracked down some code on a different forum that looks like a good starting point for using an arduino nano. I poked around, and found some code on GitHub as well.

so far, we have a $10 motor, $10 esc, i found a deal on amazon for the nano generic (elegoo) w/o pins installed (but included) 3 for $13.86

i'll have to play with the codes. it'll be a flash before sending thing, and if they want to play with the code, go for it! open source here....

so, i'm at $24 bucks so far..... this $60 price point is looking doable.....

Tim Wescott · « **Reply #22 on:** April 20, 2019, 09:30:42 AM »

Quote from: T.J. Vieira on April 18, 2019, 09:19:01 AM

i'll have to play with the codes. it'll be a flash before sending thing, and if they want to play with the code, go for it! open source here....

If you start a Git..b project for this, ping me -- I'll review your code.

CircuitFlyer · « **Reply #23 on:** April 20, 2019, 09:09:31 PM »

For the last little while, I've been playing around with an Adafruit Feather M0 Express (Arduino compatible). I have a working sketch for a rudimentary timer already worked out. If you wanted to start a project I'd also like to help if I could. My workbench is already set-up to test run some code when you're ready.

Paul

Tom Vieira · « **Reply #24 on:** April 22, 2019, 12:46:17 PM »

cool! thanks guys!

john e. holliday · « **Reply #25 on:** May 17, 2019, 10:46:46 AM »

So where are we at on this project?

FLOYD CARTER · « **Reply #26 on:** May 17, 2019, 11:39:55 AM »

I happen to be an electronic engineer (retired). I've designed many circuits using the 555 timer I.C. You can set one to provide a constant pulse to run a motor controller, but it will not stop by itself. So it will run until the battery goes dead. Adding other circuits to provide a time-out complicates the project.

Actually, a dual timer (556) is required. One stage to generate a constant rep rate, and the other as a triggered one-shot to generate a pulse of 1.5- 2 ms.

Timers designed for our e-planes contain a lot of circuitry and functions. They are not expensive, and they are small and adjustable.

Matthew Weinle · « **Reply #27 on:** August 04, 2019, 11:31:05 AM »

OK, I know that this is all the way from Blighty, but if you want a cheap, easy way back into CL this is what I am going to use: see my RCGroups link below for Dens Models Supplies ACE +:

https://www.rcgroups.com/forums/showthread.php?3363821-The-fastest-and-easiest-way-to-get-%28back%29-into-Control-Line

Tom Vieira · « **Reply #28 on:** August 05, 2019, 08:44:24 AM »

hi guys, sorry, project got shelved for a bit... bit off a bit more than i could chew this spring/summer building stuff to enter a mess of events. it's still simmering in the back of my head! i need to clear off the bench and get going on it!

Tim Wescott · « **Reply #29 on:** August 05, 2019, 09:22:04 AM »

Quote from: FLOYD CARTER on May 17, 2019, 11:39:55 AM

I happen to be an electronic engineer (retired). I've designed many circuits using the 555 timer I.C. You can set one to provide a constant pulse to run a motor controller, but it will not stop by itself. So it will run until the battery goes dead. Adding other circuits to provide a time-out complicates the project.

Actually, a dual timer (556) is required. One stage to generate a constant rep rate, and the other as a triggered one-shot to generate a pulse of 1.5- 2 ms.

Timers designed for our e-planes contain a lot of circuitry and functions. They are not expensive, and they are small and adjustable.

You can generate the correct pulse from a single 555, but you have to play a trick (you need to bypass one of the resistors in the typical astable circuit with a diode) to get the duty cycle less than 50%.

You need a sequence: 1ms pulses so the ESC "sees" a transmitter at idle, then 2ms pulses (or whatever you want for throttle) for the duration of the flight, then back to 1ms to shut the motor off.

So, a 555, a 4060, some logic -- you'll have at least three DIP packages on a board. Or you can get an 8-pin microcontroller, write less than 100 lines of assembly, and do it all with several thousand times more transistors, but just one package. Life's kinda crazy these days for circuit designers.

Tom King · « **Reply #30 on:** December 24, 2019, 08:46:22 AM »

Hi everyone,
I Started in the aviation hobby with a Magician 15 powered by a Fox .15 with my dad. I went on to build many .049 models and then on to RC. Recently I got back in the hobby after 4 years off and selling all my stuff. I started making the Foam Board planes from Flitetest.com. Then I started just downloading the plans and building from there.
Where I'm going with this is I want to use their building techniques to build a U Control combat plane. The motor and speed control could be purchased from Amazon for about 25$. The airplane parts are less than 5$ from the Dollar store. The things I need help with are the lines, Handle, Timer and design help since the only combat planes I ever built were from kits.

john e. holliday · « **Reply #31 on:** December 24, 2019, 10:58:05 AM »

Well Tom, I suggest you take a day when the weather is not good for flying and just start through this forum and read. There is so many thing/variables to state what you need. If you are going electric there should be enough to get you going after a couple of days reading. Of course some of it can be ignored and some can be helpful. Your decision.

Author Topic: CHEAP 1/2A idea (Read 2963 times)

Tom Vieira

Tom Vieira

Tom Vieira

Tom Vieira

Tom Vieira

Tom Vieira

Tom Vieira

Tom Vieira

Tom Vieira

Tom Vieira

Tom Vieira

Tom Vieira

Tom Vieira