Radio Control 9

Long saga, buggies done:







State the obvious, 4 sequences of 4 aspects.
1st aspect front right, 2nd aspect front left, 3rd aspect rear right, 4th aspect rear left.
Each sequence shows original real car then photos of 2 models underneath.
The engine has separated from body on the model with standard Fly Sky receiver / transmitter controlled model. I'll have to re-glue that.
I'm a bit disappointed in the model quality, but they will have to do.

I'll publish the monster buggy when it's complete.
But that will have to wait as my printer is out of action, every 2 years the Arduino 2560 fails, this has happened twice and in the same very weird way, the ADCs seem to lose accuracy, the hot end appears ok at room temperature but up at temperatures needed (250 degrees C) it is actually much lower temperature. I've ordered a couple of replacements, awaiting arrival from China.

Radio Control 8

Beach buggy bodies ok, still brown over spray to do.
Monster chassis with wheels in front.

Radio Control 7

Decided to cut it short, yes I'll create the bodies and they will be accurate, but the main purpose is to test usability of my ESP8266 RC module against standard RC kit.

Twin rolling chassis, yellow tape is my module, brown tape is standard FlySky receiver.

Left is standard ESC and all wiring including switch, charge sockets, connectors to batteries.
Right is my module with piggy backed ESP8266-03 module.

Same on left, right is FlySky 4 channel receiver.

The compare very well in operation, I think my module is good enough.
Now to finish off, got 2 bodies printed, put together and rubbed down. Got Airbrush and paints on order. Bodies clip on well.
Whilst awaiting painting gear, I may well get on with monster mod, both Grand Children are eagerly awaiting their buggies with monster truck wheels, should then work on lawn.
Then I'll package it all up and publish on Thingiverse.
Not sure how Thingiverse will the whole design with module, PCB etc. Should be interesting.

Radio Control 6

Ok, so I was wrong, my dad said it looked too long and thin, searched web, the drawing I was using for the dimensions was wrong, whole front end was wrong. so I redesigned, it's different and fully useable :-)

Design from a long time ago, engine mounted cross wise, 3 stage gearbox, rear battery pack containing 5 off AAA batteries, front axle wrongly positioned. OpenSCAD exported image.

New design, engine mounted where it would be on a VW Beetle, 10:1 small worm drive gearbox, Li-Po batteries built into clip on command module, front axle correctly positioned, all wheels correctly placed. OpenSCAD exported image.

The actual model, mostly in coffee coloured PLA, original car chassis was painted in similar tan colour. wheels in white colour PLA and sprayed silver. Dimensions are correct, speed is scale 70 mph like original, I also just printed the a second set of parts and made the PCB for my controller, with luck have that assembled tomorrow.

I have body designed, have to print in 2 parts, working upon support to get the weird shape to print, NOT looking too good yet:

Radio Control 5

Rolling chassis is only perfect, but will have to do:

Wheels are perfect in functionality and look (they look just like original buggy), front wheels and steering are nice and loose with no wobble, motor and gearbox are spot on, full speed range from very low to reasonable (but not stupidly fast) top range, steering range is as good as real thing, motor stays cool. I am pretty chuffed.

On with body, maybe after I turn it into monster truck with big pneumatic tyres, or a standard VW beetle, maybe publish with a number of choices :-)

I have coffee, silver and yellow filament coming next week, so I'll create a couple in correct colours, keep 1 as above and fit my controller to the other, then I can test my controller properly :-)

Radio Control 4

It works!!!!!!

Ok, it's just a rolling chassis, had to fit slightly more powerful motor, motor needs better mounting, steering is not particularly good, wheels are not good, but it's getting there, I can drive it around, speed range is nice.

Radio Control 3

This is all way harder than I originally imagined.
I have working. neat little RC controller module based upon ESP8266. To further understand, skip back to my April 2016 post.
I want to test it in actual models, I had 2 types in mind:
Trix: a 70 year old sailing boat.
Buggy: a mini remote control car.

Trix: Kind of fallen in a heap, nothing to do with controller RC or electronics. It was originally built by my grand father as a toy for his son (my father), back then it was all mechanical self steering. Roll on a few years until around the 90s when my kids were not yet teenagers, I fitted it with crystal RC, 1 servo for rudder, a 2nd servo with long arm to pull in the main sail. The rudder worked so well that it didn't matter that the arm was useless. We spent a week end sailing it around the lake at Wellington Country Park, kids played solid. Then my Dad turned up and was quite distressed that the wooden hull was totally soaked. He took it away and I didn't see it again until recently.
I got it back, it has been coated inside and out with a thick coat of resin. I rubbed it all down, under coated and painted white all over (original colour, white main, red base). I was just going to put a line around it and paint the base red. But my Dad tells me that is not correct, with sail boats the line MUST be the water line. So, I fitted all the deck fittings, rigged it all up and floated in the bath, marked the water line, then painted the base red up to the water line. My Dad was not available for any of this. Ok, all done (I thought), than my Dad comes around, the water line is much too high!!! It won't sail properly!!! So basically, scrap everything I've done, rub it all down to remove the paint and some of the excess resin, then float it and adjust the keel weight by drilling out the lead and filling with filler, then I can re-do it all over again. I've put it back in it's box, I'm not in any rush to re-do months of work.

Buggy: This is way more difficult than I ever imagined, build a toy car, how difficult can that be?
See fully in June 'Radio Control 2' post, but basically "Put receiver into Buggy, not so good, it works perfectly off load (lifted off floor). It won't drive for long even on a flat smooth level floor. The cogs bind, probably too much play. I'll probably redesign to use worm gear drive. Again, once I get it working with standard transmitter / receiver then I can play, get to know it then switch over to my controller. Cut out all the variables."
I've moved to a standard FlySky receiver, I've created a whole involute gear library so I can create a worm drive gearbox, it still does not work:

The motor is a standard MR2, this may not be up to the job.It's now got a 10:1 worm drive gear box. I powered it with a 2 Amp bench supply. Going from still to motor moving is hard, I should have thought, but a motor is basically an electro-magnet which is basically an inductor, it's going to need a large current to get it started then it will settle down to a lower current, takes up to 1.5 Amps to get it moving, any alignment issues with motor to worm or worm to axle and it just won't start. But it works very well on bench supply! anywhere between 2 to 6 volts, it's a current issue. Switch to my battery box (in background) with 5 off AAA batteries and motor won't start, I thought I had issues with contacts making to battery, switched to standard 4 battery holder, still doesn't work. It may work with a large capacitor in the circuit to supply the large start up current. But if the motor is on load, at higher speeds, it pulls down the voltage enough the interfere with the steering servo.
I have some 3.7V lipo 5-10# batteries, will give them a go.
I thought this would be so easy!!! Half thinking about buying an off-the-shelf RC Car kit to test my receiver, but I'm not ready to give up quite yet. Writing this has helped me get it straight in my mind.

Breaking news:

Lash up, 2 lipo 3.7v batteries in series (7.4v) and it works :-)
Re-design to do it properly, watch this space......

InvGears2

New version, see here:
http://www.thingiverse.com/thing:1654911

I no longer like the bevel gears in the lib, will deal with them later.
Now got worm drive, created manual examples, 2 sizes, both work much nicer than I expected, next I'll try in ABS with a 500 rpm motor, see if it works or melts!

The worm algorithm is quite 'sexy'.
set:
iShowC = 1;     // 1=Show all calculation circles
iShowT = 1;     // 1=Show all calculation tangents
iDemo = 1;      // include demo code

In InvGears.scad, you now see just the points that make up the worm:

It's even nicer in OpenSCAD where you can view it from different angles.

Now set iShowC to 0 and re-build and you see worm surfaces:

See how ends are flattened so it keeps to correct length? That is accomplished using 'conditional', see OpenSCAD manual.

InvGears.scad

I had trouble with my RC car design, needed to get the gearbox working much better.
So, I created InvGears.scad.
See
http://www.thingiverse.com/thing:1643825
All files NEED OpenSCAD version 2015,03-02 or later they will NOT work with previous versions.
InvGears.scad is meant to be used as a library for use in other scad files.
Everything is still very much work in progress.

Example.scad demonstrates it's real use.
This contains a parametric 2 stage, 3 axle gearbox.
Variables near top of file control the parameters of the gear box:
Pitch sets gear tooth size and therefore ultimately controls size of gearbox. On my printer 0.7 is about as low as I would go, 0.8 for higher print quality.
The rest of the variables are documented in the file.
Un-comment gAssy() to see just the gears, use OpenSCAD View|Animate menu to see the teeth movement for adjusting Pressure.
Typical gAssy() view:

Comment out gAssy() and un-comment Assy() to see full assembly.
Typical Assy() view:

Comment out Assy() and un-comment print1() to get printer plate of housings (parts shown in white above).

Comment out print1() and un-comment print2() to get printer plate of gears (parts shown in red above).

In both printer plates there are extra cubes.

I created my printer in 2013, it's a RepRap metric Prusa with home made hot end:

Your printer probably creates better quality prints, to be honest I have no idea how the quality compares. You will see that my printer has NO fans, I find that adding cubes to my prints allows the plastic to cool down between layers so that it doesn't go wrong, the cubes are my alternative to fans.

I did say that the files are work in progress, the Example supports Spur, Helical and Herringbone gear types only.

InvGears.scad:

The file can be used on it's own to see how it all works.

There are 3 variables near the top of file:

iDemo = 0;

Set this to 1 and the you will see output.

Variables similar to those found in Examples.scad are further down in file, these control what is shown in demo.

iShowC = 0;

Set this to 1 and you will see the 4 circles of interest for the gears.

Please refer to http://www.cartertools.com/involute.html by Nick Carter to fully explain.

The 4 circles show Outside, Pitch, Base and Root as explained by Nick Carter and shown in his first drawing.

It also shows the 2 radii that define each side of main tooth.

iShowT = 0;

Set this to 1 and you will see the involute point calculations, radii and tangents.

These show up best with Rim, Adj and Typ all set to 0.

This is explained best by Nick Carter in the rest of his drawings and explanations.

Once you get to this stage you can alter the other variables and see the difference they make clearly.

Don't forget to set iDemo, iShowC and iShowT back to 0 before using the lib in your files or Example.scad.

InvGears.scad also includes bevel and cycloid gears, but I have not yet created an example for those.

Mini Drawers

In my last post I wrote:
"Whilst awaiting, I now have lots of very small parts, M1.6 washers and nuts, M2 washers and nuts etc. I have no place to keep such tiny components, so I'm creating a modular clip together drawer set.
Clip together is not an easy concept to make work in 3D printing."
It's now obvious to me that I know little of what people want!
I published as http://www.thingiverse.com/thing:1621667
231 views, 60 downloads, 40 likes, 48 collects, 1 make!!!!
Published last night at 12:33, this is stats from less than 24 hours!
The world is nuts!

Radio Control 2

Ok, cut down variables, ordered FlySky FS-i4 4 channel transmitter, I had 1 but gave to my dad for controlling his speed boats, I have a few FlySky 6 and 4 channel receivers that will work with it.

I'm concerned that AAA batteries are not good enough to drive the buggy, so I've ordered some Lipo batteries and a multi-charger.

I've added level changer to the controller PCB, made the PCB then discovered I have no PCB drills left, tried a lesser quality drill and messed up the PCB, so I've ordered some more.

Whilst awaiting, I now have lots of very small parts, M1.6 washers and nuts, M2 washers and nuts etc. I have no place to keep such tiny components, so I'm creating a modular clip together drawer set.
Clip together is not an easy concept to make work in 3D printing.

Lipo batteries arrived, multi-charger has 1 type of connector, batteries have another!!!!
Ordered some leads of each type, will make up patch leads when they arrive, but for now I can't use the batteries (sigh).

Transmitter arrived :-)
Put into Trix controller, it now appears to work perfectly on desk. I can build up the complete model, test it, get to know it, then switch to my controller and compare. Still lots of fiddling, I now need to put back all the deck hardware, set it all up, float it to get water line, paint bottom red up to water line.

Put receiver into Buggy, not so good, it works perfectly off load (lifted off floor). It won't drive for long even on a flat smooth level floor. The cogs bind, probably too much play. I'll probably redesign to use worm gear drive. Again, once I get it working with standard transmitter / receiver then I can play, get to know it then switch over to my controller. Cut out all the variables.

Basically, all on-going, nothing completed yet. 

I forgot how much smaller my controller is than a standard receiver, that was pleasant.

Radio Control 1

I had 2 models for testing the Radio Control unit.

Model 1: Trix:
This is a sailboat, boat itself is about 70 years old, roughly 3 feet long, 5 feet tall with sail.
It has a hatch in centre that allows access to an internal handle.
I designed an insert to take the control mechanisms, 2 servos, a simple 9g servo to control steering and a winch servo to control sails.

Model 2: Buggy:
This is a remote control beach buggy, should look like the beach buggy my father designed and built back in the 70s.

Trix had been taken down to basic shell and coated with resin to make it waterproof, so before I could start in earnest I had to prepare and paint it, so I tended to concentrate on the Buggy whilst spraying the coats of paint on Trix in background

This is the basic Trix shell, now painted white, I need to put back all the fittings, get the electronics working then float so I can get the water line before I can paint the red underside.

This is with the electronics module fitted.

This is the electronics module, 3D printed out of red PLA, sprayed white to match Trix. The top small box clips off to allow changing of batteries in situ. It holds 4 off standard AAA batteries.

2 nylon cords are routed through PTFE tubes from correct position on deck (for sails) to winch servo.

Power switch on top, small 9g servo for connecting to rudder.

Buggy is a fully printed new design from scratch.

Top is a photo of me in my fathers original Beach Buggy, note it's a banana, yellow with brown patches, 4 banana linked for steering wheel, green banana leaf bucket seats.

Middle is a photo of current printed model.

Bottom is a picture export from OpenSCAD.

No body (yet, half designed).

I'm really happy with the tyres, they are Oogoo set in PLA printed moulds.

Oogoo 1:1 cornflour:silicon with black printer ink added, nice rubbery texture, grip well.

The steering was surprisingly easy. The floorpan in accurately based upon the VW Beetle chassis with 12" removed as used in any full sized beach buggy. The motor is a standard MR2. I had lots of problems with the gear box, I could not get the standard OpenSCAD gear library to create gears small enough, so I used my old involute gear library I created for my failed clock. Currently 10:1 using 4 gears.

Trix is basically simple, control modules, 4 AAA batteries, 2 standard servos, but it's not something I can publish, I doubt anyone else has a boat like Trix.

Buggy is more complex but publishable, once complete I can publish to Thingiverse and anyone can build it. It has control module, 1 standard servo, 1 standard ESC, motor and gears.

Everything works on the bench. Connected up to bench PSU it all runs perfectly. As soon as I try to get it to work for real then it goes nuts. To start with I had 4 off AAA in the buggy, batteries all in series (4 x 1.1 to 4 x 1.5 = 4.4 to 6V) connected to ESC, 5V output from ESC to control and servo.

As soon as I put onto ground and try to move it then it resets. Phone appears to be really bad at handling resets, the wifi hot spot gets interrupted, so the browser no longer connects.

I tried 5 batteries, I tried 5 batteries plus 1000uF capacitors, no good.

I removed the regulator from the control and had 2 batteries into control and 3 batteries into ESC/motor. Nothing satisfactory, ordered some Lipo batteries and charger, put it on hold.

Moved to Trix, nice and simple, should be easy?

No, that doesn't work either. I think a big part of the problem is that the controller is 3V3 based.

The servos do not seem to like being powered by 6V and driven by 3V3, they make odd noises and draw lots of current.

I may try to add level conversion to control module, I may just switch to FlySky RC equipment for now and get on with turning the control module into a tiny quad copter, not sure yet.

Radio Control

Not added to blog for a while, been out of action, my Jack had crusciate ligament surgery, he wasn't allowed to jump at all, so kiddie gate on bedroom door, bed out, mattress on floor, we all lived like like in bedroom together for a year!!!!!!!!!!!

Now I'm back to playing.

ESP8266, got a few different modules, had 4 off ESP8266-03, and it's smallest with a decent amount of GPIOs, so that's the one I started with.
Fitted it to a 0.1" jig, plugged into breadboard, plugged in a USB to 3v3 TTL module, added a few resistors and LEDs.
Setup Arduino, got it programming with examples, modified examples.
Added a 3v3 regulator and a couple of capacitors.

Created a 3v3 regulator / interface board:

Software is a mixture of various examples.

Turn it on and it becomes a Wifi access point. Connect to it with a WiFi device (I use my Samsung mini 4 phone). Open a browser (I use Chrome), navigate to 192.168.0.1, it shows a radio transmitter:

Multi-touch, finger touching right side acts as the right joystick of a standard radio control transmitter, finger touching left side acts as left joystick.

Positions of fingers are passed back to module and it uses those values to drive up to 4 servos.

It's all fully working, it works with standard Futuba (large) servos, it works with small 9g servos, it works with an 10A ESC that I connected up.

The web page is based upon:

http://sebleedelisle.com/2011/04/multi-touch-game-controller-in-javascripthtml5-for-ipad

This includes an html page and a javascript page.

I created an MSVS 2015 project to compress these so they can be stored as static text in the main Arduino program.

The Arduino program uses ESP8266WiFi, WiFiClient, ESP8266WebServer, Servo and EEPROM libs. The program itself is stiched together from various examples.

Basically: It scans all current Access Points, chooses an unused channel. Loads SSID and Password from EEPROM, uses these to create an Access Point, it then sets up a web server.

Web server serves up main web page and javascript (as explained), it also allows 192.168.0.1\config page that allows Title, SSID and password to be changed and saved to EEPROM.

(Title is "Trix" in this instance, shown on joysticks main page).

I have a couple of ideas ready to use this module, then I can test it in anger (so to speak).

Costs: About £5 for all the components shown.