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......
