Large Scale Central

Downsizing / Repackaging a 2-Stick 2.4 GHx Transmitter

Electronics Power and Sound
#61

No problems Kevin.
You might ask why pushbuttons appeared in the first place.
When battery R/C first started the biggest problem operators faced was the destructive phenomenon of “Glitching”. This is where sudden spikes of RFI caused locos to jerk backwards and forwards for no apparent reason, often destroying gear trains.
I first overcame that in 1988 by using the backwards and forwards movement of an elevator stick to create momentum control. This completely eliminated “Glitching” but RFI occasionally caused the signal to drift with the ESC’s sometimes accelerating and braking on their own. That was still evident until 2.4 GHz stabilized the signals so that it is no longer a problem.

In the meantime Neil Dyson and I worked out a way of utilizing the digitally encoded signals from a popular Australian made garage door opener made by Elsema. Using pushbuttons to do what the stick had done solved all the problems and everyone else copied my idea. This was the very first proprietary LS battery R/C system offered for sale anywhere. The only real drawback was lack of range.
A few years ago Elsema came out with a more powerful TX hand piece which they modified to 8 buttons for me. Range was better but still limited because of the inherent RFI problems with 27 MHz.
Pushbuttons were a means to an end that have lingered on for too long. To me pushbuttons are still less than ideal for speed control. DIGITAL PROPORTIONAL speed control is still the most user friendly method.

The obvious drawback of using the commercially available 2.4 GHz R/C is the size of the TX. It is my ambition to commission a smaller purpose designed hand piece that has DIGITAL PROPORTIONALspeed control.

Maybe one day.

#62

Jon. Del has drawn up what you need. He said to E mail him for them.

#63

Dad’s solution to glitching was to have the system average the signals over a second or so. This “filtered” out the stray signals unless for some reason it got really bad. It took a few revisions, but by the 90s, we had a solid system in place. There was a slight delay between moving the throttle stick and the locomotive’s response, but it really wasn’t that noticeable (and is actually about the same as what we see with the current throttles.) For the whistle, as soon as it was “turned on,” it shortened the averaging period to a much shorter time so to have faster response for “playing” the whistle. In many ways, I miss his old analog systems. We could do some cool stuff with them that still haven’t made their way into the digital realm. (On the other hand, the bell sounded like …)

When the commercial sound and throttle systems got to where they could do everything we needed them to do, dad quickly retired from making his own throttles in favor of the ready-made stuff. (It also coincided with me moving out of the house and starting my own railroad. I don’t know if it was so much he didn’t want to build himself any more throttles, but he knew my tendency to turn out locomotives at a fairly quick pace and didn’t want to have to build me any more. :wink: ) The convenience of ready-to-use stuff outweighed the sacrifice of the proportional throttle.

How I see it, we’ve already got the Airwire and NCE controllers that have a parallel to the proportional throttles we used to use. (It’s not quite exactly the same, but very close.) We don’t need another version of that. If what we’re talking about here is to have any competitive advantage, all the channels have to take advantage of the proportional control–throttle, direction, whistle, etc. Otherwise, it’s just more of the same, with no incentive for the user to switch over from the competing systems.

A few things need to happen. First, we need to lean on the manufacturers to offer more proportional functions on their systems. For instance, QSI’s sound system offers the ability to manually control the volume/cadence of the chuff. It does this by mapping the throttle keys to control that. The problem is that you can’t change the speed of your loco while using the throttle to control the chuff. Seems to me it would be a very simple programming change to map that to a second proportional channel, so you could simultaneously control both. A quillable whistle is doable if you go from using a strict digital recording to one that’s a digital model of a whistle. We’re seeing this more and more in digital musical instrument voices. It’s not the old-fashioned analog synthesis, but draws on digital samples to create sound behaviors based on how the instrument is being played. Right there, you’ve got three proportional channels giving you unprecedented control over your locomotive’s sounds and throttle.

Second, I think you use the live steam market to demonstrate that a smaller form factor is of significant benefit. This, I think, will be a bit harder, since there aren’t many live steamers who actually “operate” their locomotives to where they need the extra hand free the way those of us who do prototype ops do. But still, if you can demonstrate that they can run the train with one hand while holding a (beverage of their choice) in the other, you might gain some converts. Since many of us run both live steam and battery, the crossover market could have a great deal of potential. Sell people on the fact that the same operation controls both electric and live steam locos.

Later,

K

#64
TonyWalsham said:
Jon. Del has drawn up what you need. He said to E mail him for them.
I have what Del drew. It is a single two position centering toggle to replace the pot. That is very straightforward and I had already worked that one out. What was driving me crazy was trying to work out splitting that toggle to two push-buttons - on for full left, one for full right and to hold center when at rest. After perhaps a hundred different attempts I finally have a design that will work using only two resistors and two push-buttons. I must have had a real mental block because when I finally hit on the design that worked it was much simpler than where I started.

I will post a drawing as soon as I can do it electronically - you don’t want to see my hand sketches :slight_smile:

#65

OK - had a chance to draw up my Stick replacement circuits in Visio… [url=lsc.cvsry.com/Post/EquivilentCircuits1280.jpg]

(http://lsc.cvsry.com/Post/EquivilentCircuits-800.JPG)

[/url][color=blue]FF: Click to Enlarge - IE: Right Click Photo and select Open Link in New Window to Enlarge[/color] EDIT: You can find Del’s drawing here http://lsc.cvsry.com/Post/DIY_TX_Hack.pdf EDIT #2 Del warned, and I confirmed, that in my dual push-button circuit there is a short circuit the presented to TX if both buttons are pushed. There may be a way to build in some protection, but I haven’t looked at that yet. My brain hurts from just getting this far. EDIT #3 - I updated the drawing removing the possibility of a short if both buttons are pressed. The new configuration will output Position #1 if both are pressed.

#66

Back from a week away at a live steam meet 800 km from home.

Most of the live steamers I spoke to are quite happy to stick with regular low cost stick radios. It is just not a big deal to them.

The battery R/C participants will put up with the stick radios but would like the TX to be smaller and operable with one hand.
From a commercial point of view it may be reasonably inexpensive to produce a TX handpiece that uses a Digital Proportional knob for speed control with momentary only, center off switches for direction set and trigger functions, plus a push buttton for binding.

It would not be economically feasible to add all the servo trimmers and servo reversing switches to the hardware.
However, given that the lowest cost brand, which I really really like, can already program those settings via a computer, I see no barrier, other than development money, to a small, simple TX handpiece with Digital Proportional control of the speed for battery R/C. The only problem electrically I can see is providing a kill button for emergency stop situations. No doubt that could be worked around successfully.
Live steam controllability would be less than optimum, but nonetheless, doable.

#67

Tony, with the only proportional aspect being the throttle, where’s the competitive advantage over the other systems? Airwire and NCE already offer proportional control. (Airwire’s basic throttle is proportional, their more expensive throttle and NCE’s aren’t exactly, but the notion is the same). Seems to me that you’re imposing artificial limits on the capabilities of your system–perhaps not now with what it currently can do, but in terms of future functionality. If you dump all this money into a new, smaller handpiece with a proportional throttle only, then Phoenix comes out with a quillable whistle or QSI links their “labored chuff” to a second channel, you’re back to the drawing board and out even more development costs if you want to take better advantage of it.

Personally, with only 4 (or 5) channels, your system is already at something of a disadvantage compared to the rest of the field in terms of the number of functions that can be controlled. Your greatest strength is to be able to control those 4 or 5 channels in a way the others can’t–i.e., proportionally. Frankly, if the only proportional channel on a smaller handpiece was the speed, I wouldn’t waste my money on it. Put proportional control over four channels, and I’ll be the first in line. I’ll happily use it for my live steamers, and then when (and I’m certain it’s a matter of “when”) the sound guys work proportional control over their sounds into their controls, I’ll be fully ready to take advantage of that with a transmitter I can run with one hand.

Later,

K

#68

@Kevin: You forgot to bold proportional. :slight_smile:

#69

The advantage will be LOW cost and lack of complexity.
I guarantee you four regular sound trigger functions will be enough for anyone.
As the RF would have 6 channels an extra quillable sound control would be available.
If anyone wants more channels they can use a full size stick radio.

#70

Am I going to have to enroll in the College of Engineering just to enjoy my hobby?

#71
Steve Featherkile said:
Am I going to have to enroll in the College of Engineering just to enjoy my hobby?
Isn't that pretty much required just to make this post, watch your TV, or use your cell phone? If you enjoy your hobby now, just don't change the way things are now. Simple. (Besides, like many other things, many enroll. But not all graduate.)
#72

It just dawned on me… what we’re talking about pretty much already exists. Pistol-grip style transmitters. You can hold them with one hand, even control the speed with that same hand. You’ve got fully proportional control over multiple channels. Cost? Anywhere from $100 to $500+, but the $100 systems would give us adequate control over throttle, direction, and at least two sounds–probably adequate for many.

Later,

K

#73

'Fraid not.
Roundhouse tried selling them to customers for a couple of years, with a singular lack of success.
The trigger speed control is more OFF and ON than proportional. Plus, they are still way too big to fit in a pocket.

#74

I agree with Tony here. My “Quick & Dirty” R/C experiment on my Shay was done with a pistol style transmitter. I used the steering channel for the Johnson bar. It sucked. Both the steering and throttle channels on a pistol grip are spring center return.

I haven’t seen 2.4 GHz pistol grips in the low price range - but then I haven’t been looking.

#75

Okay, I’ll go back to my original thesis that I was developing when I remembered the pistol grip R/C controls. (Incidentally, I use one for one of my locos with great success. You take the centering springs out of the trigger and knob.)

Why does this unit have to be “low cost?” The “low cost” option for control would be the standard 2-stick transmitter. You can get those pretty inexpensively. If you’re going to try to undercut that, you’ve got a tall, tall order ahead of you. It seems to me that a smaller, hand-held controller with proportional control over multiple channels would be a premium controller. Compare the basic AirWire controller to the NCE G-wire controller. The AirWire controller has a knob, direction switch, and 10-digit keypad. That’s it. The NCE controller has a thumbwheel and buttons galore. You can program macros, options, any number of things. Ultimately, both do exactly the same thing, it’s just how they do it–and how the user interfaces with it–that’s different. It seems to be worth the premium, as people like it. You don’t “need” it, but it sure makes running the trains a bit more intuitive.

In my opinion, the same would hold true here. If you want the basics, you go with the cheap 2-stick controllers. You get all the control, but in a form factor that’s far from convenient. However, for an additional price, you can get a smaller, handheld controller that offers the same level of proportional control in a smaller package that’s easier to carry around the garden. There’s no reason it needs to be as small as the RCS Elite controller. I think you could easily get away with something the size of the Revolution or Airwire or old Train Engineer controllers. That seems to be an acceptable size range based on what I’ve heard people say. I personally think the NCE controller is a touch larger than ideal, but that doesn’t keep me from enjoying using it, either. It’s still one-hand control.

Forgive my frankness, here, but through all this discussion, I keep hearing an overall tone of “it can’t be done.” I’m not convinced. I’ve not heard one shred of evidence why you can’t fit three, four channels of proportional control in a small, handheld package. Even if the pistol-grip transmitters aren’t ideal, they do put all the controls in the head of the transmitter. Cut the handle off, and it’s about the size of the old Train Engineer transmitters. Can it be done for less than $200? That, I don’t know, but what I’m hearing is an overarching reluctance to even consider it for fear that it might not be. To me, that’s a bit backwards. Work on the ideal, figure out how physically to make it work, then start figuring out how to produce it fairly cost-effectively. If–at that point–you find it can’t be done, then start paring down functions. But by choosing from the start to only produce one proportional control, I think you’re going the wrong way about it.

I started off with using 2-stick controls, and will never go back to them. They’re cumbersome, plain and simple. For my fire-breathing dragons, the pistol-grip controls hold promise. They’re not ideal, but they’re a step up from 2-stick controls. At least I can use one hand to control the throttle. I’d love something even better. Give me a small form with comparable functions for around $200, and I’ll write you a check. But I need proportional control over more than one channel, plain and simple. Don’t do that, I’m not interested.

Later,

K

#76

Please define proportional control so I can follow this discussion. Why is it so important?

#77

I’ve been reading this with interest. I come to large scale RC control with a pretty long history of RC flying so I don’t see a problem with the two stick radios. One thing that hasn’t been mentioned is the use of a neck strap. I went to flying with a neck strap about 15 years ago and have found that helped out a lot. You can operate with one hand particularly if you’re using something like Tony’s or Del’s systems (set the speed and let go and operated other functions with one hand with the TX hanging in front of you).
Having something that fits into a pocket or is the size of an NCE controller would be nice but I do like the low cost of the 2.4 ghz transmitter/receiver combos from China.
Dave

#78

This BELTROL started off with the idea of eventually becoming a BELTROL. Is that still happening, Tony?

#79
Steve Featherkile said:
Please define proportional control so I can follow this discussion. Why is it so important?
Proportional means the speed is proportional to the position of the stick, as opposed to pushing it up to increase speed (center return via spring) or down to decrease speed. No return springs. The stick position stays where you put it, and indicates the speed. Add momentum to the equation, and you can just quickly set your desired speed setting and watch it ramp up to speed.

Dave: As to neck straps, that was the first thing I tried with the stick radios. I hated it. For one, you can’t just walk around with the thing hanging around your neck unless you keep your hands on the controls. You will bump the speed setting stick.

I find it very easy to just carry the Tx in one hand, and set it down just about anywhere when I don’t need it.

#80

Del, Thanks. I have an old Velvet Touch throttle that uses a 75 mHz 2 stick without proportional control. I hate it.