Large Scale Central

R/C advice needed

Electronics Power and Sound
#1

Hi, I need some help here. Not knowing beans about R/C, I’m wanting to employ it on a very small (1:24) railcar based on the AMT Model T kit. I was going to do a “build thread” on it, but I haven’t because I’m crashing and burning on this control issue.

So, here goes.

  • Motor: can be 3 or 6v; and at 6v has a 1.6A stall current.
  • Batteries: I have room for 4 AAA batteries (though I’d rather only use 2, but I think I have to get it up to 6v).
  • I’ve looked at Deltang, TrainLi, G Scale Graphics… but there are RX size and battery size and overall price issues. Tam Valley has neat stuff, and I DO run DCC. But I wanted this effort to be applicable to other layouts, without the DCC.
  • I’ve also looked into HO scale “dead rail” products (thanks to Jerry B.), but haven’t found a non-DCC approach there.
  • Micro RX+ESC units abound, many for $20, which would be great. But, I’d really want to have a small, sensible handheld – like the Deltang – and not the two-joystick overkill that is assumed for those generic units.
  • I understand (from Tony Walsham, thanks Tony) that the generic RX+ESC units don’t accommodate fwd/reverse. Ugh…

Does anyone have any ideas on a comparatively low-cost product line, or package, or component, that would help me with this riddle?

  • A small / simple hand-held controller
  • A tiny (like 1" x 1/2") RX+ESC, with BEC (I’m proud of myself that I now know what those mean, even though I don’t really want to)
  • Provides fwd/reverse & speed control
  • Works with a brushed DC gearmotor
  • Runs on 6v (I guess 3v is too much to ask for)

Thanks for any guidance!

Cliff

#2

I can’t help you on the TX/RX, but if you go with Lithium-Ion batteries you can get 7.2V from 2 cells that are just a little bit bigger than AA cells.

I use Dell’s Railboss with a 2-stick radio. The on-board equipment (ESC and RX units) a pretty big so they don’t lend themselves to small locos. I had a hard time cramming 4 cells, RX, ESC and Sound in a Bachmann Porter.

That said; I think some of the Detang and Tony’s TX units will replace a 2.4GHz 2-stick radio in a smaller package. I have been considering going down that road for a while.

#3

That’s a tough design goal. Would a smartphone be ok for a controller? ie bluetooth?

The key would be a tiny fwd/rev speed controller.

http://www.banggood.com/10A-ESC-Brushed-Speed-Controller-For-RC-Car-And-Boat-p-908719.html

Is this one small enough? How many square inches to you have to fit electronics into?

#4

Thanks John, I’m looking into lipo’s, though the higher maintenance requirements puts me off. Is that not a big deal? And I’ll look at Tony’s stuff again, I guess I missed the TX. [edit: the GSG receivers are relatively huge, so no joy there I’m afraid]

Thanks Martin, I only have a dumbphone (CrackBerry, required by my job), no smartphone. I’ve seen that receiver, and I think it would fit as long as I can also find a small RX for it. [edit: the main hood space is approx 1.0 x .6 x .6, so not much room there.]

Good thoughts guys, thanks again.

#5

Thanks for considering RCS.

Deltang had the ideal small Rx65b combined RX/ESC that would work down to around 6 volts.

Sadly I can no longer stock them as Deltang are unreliable suppliers to dealers. Deltang simply refuses to supply me and many of his other dealers.

#6

On those small Rx that don’t do reverse, use a second wired in reverse. Turn one on for forward, turn it off and the other on for reverse… Might be a work around.

John

#7

Tony, I sure like the look of your hand-held controllers. And I just saw your micro viper esc’s. But it looks like they need more than 6v (?). Not sure how big they are? And is there a micro receiver that works with your simplest (“live steam”?) hand-held?

John, that sounds interesting. Maybe use diodes to feed the two sources to the motor? Unfortunately, I don’t know squatsky yet about choosing components or controlling things to that point, haha! But thanks my brutha.

#8

Stupid question. What about the guts from a cheap, small, RC car from someplace like Walmart? I mean its just a rail-car, so no need for high amp motors. And you could scavenge and use the motor that came with the toy car. It should have forward and reverse. as for the steering, just leave those wires disconnected.

Yea, its probably a stupid idea.

#9

Hi David.

Using the guts of an El Cheapo car R/C may work OK.

Cliffy,

The VIPER-10-15 is about 1" square and requires a separate RX. Minimum is 7.2 volts.

The only viable combined very small RX and ESC is the Deltang Rx65b. They will work down to about 5 volts, but, obtaining one will mean dealing direct with Deltang.

My TX’s are expensive compared to other R/C systems on the market. However they do work reliably and although designed for Live Steam can be used with most ESC’s

#10

Cliff Jennings said:

Tony, I sure like the look of your hand-held controllers. And I just saw your micro viper esc’s. But it looks like they need more than 6v (?). Not sure how big they are?

Cliff,

If Tony’s controllers (TX) are like his old RCS stuff, they are about the size of pack of cards. Definitely a one handed operation, and could fit in a pocket.

#11

Hello Craig.

The current range of RCS 2.4 GHz TX’s are all digital proportional with knob control for speed etc. 3, 5 or 7 channels versions. The 5 & 7 channel versions have 4 x push-buttons for sound triggers.

They are the most tactile R/C hand pieces on the market.

They are bigger than the old 27 MHz hand pieces which were indeed a 20 cigarette pack size, but they will still fit in pocket.

I haven’t made the 27 MHz stuff since 2009.

#12

David Maynard said:

Stupid question. What about the guts from a cheap, small, RC car from someplace like Walmart? I mean its just a rail-car, so no need for high amp motors. And you could scavenge and use the motor that came with the toy car. It should have forward and reverse. as for the steering, just leave those wires disconnected.

Yea, its probably a stupid idea.

Along those very lines David, I bought a cheap toy RC car off Amazon a few weeks ago. I liked it because it used 4 AAA’s. But it turned out that the “speed control” was merely fwd-off-rev, no variability. So I got too cheap of a toy.

But I agree, seeing the small toy R/C’s was the basis of my assumption that something could be cheaply adapted.

#13

Cliff, yea some are either on of off. But for a small speeder, with a bit of tweaking, that might be good enough.

#14

David, if you run across a cheap variable fwd-off-rev toy, please lemme know.

#15

Cliff - not sure if you saw the notes I put together on a simple, inexpensive remote control - see:

http://www.trainelectronics.com/Articles/RadioControl_multi-channel-RF/index.htm

It is designed for 12 volts but may work with a lower voltage - the price is certainly right - adding a DPDT relay gives you forward and reverse.

dave

#16

Dave, thanks, that’s very interesting! Your circuit adds that relay, and it’s quite simple.

Not sure about going down to a 6v input though. You think there’s a chance that would work?

I didn’t see any notes on how your controller worked. Did the speed up/down step the volts up, with the mode +/- changing the direction? Or…?

Also, how did the DIY functions come into play? Were you able to program finer control with those?

Thanks again,

Cliff

[edit] Dave, here’s something similar that takes a 5-24v input. At 5 bucks I had to just get one. (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-smile.gif)

http://www.aliexpress.com/item/Dream-color-LED-strip-dimmer-controller-RF-Wireless-Remote-Controller-Free-shipping/1373540350.html?spm=2114.01010108.3.10.sXggMs&ws_ab_test=searchweb201556_0,searchweb201602_4_10017_10021_507_10022_10032_10020_10009_10008_10018_10019_101,searchweb201603_1&btsid=e431705b-d6c1-49e2-af51-9cd17267e281

[nuther edit] I read your article more carefully Dave, and saw your video, so I now understand more about how you programmed your DIY buttons for fwd/rev. But I’m still fuzzy on how you varied the speed?

One more comment, you mentioned that 6 steps isn’t great for speed control, but it would be tons better than an on/off (which is where I was heading, since the conventional rc isn’t panning out here).

#17

Here’s something neat,

http://www.sears.com/unique-bargains-dc-5v-4-channel-jog-type/p-SPM8688186123?prdNo=26&blockNo=26&blockType=G26

No variable voltage, but a robust simple gadget it seems. [edit, after further looking:] I guess there’s a lot of these kind of switches out there, not much though on cheap smoothly-variable kits though…

#18

You could always input a higher voltage to the RC device, and then use diodes to cut the voltage going to the motor.

#19

Thanks David, but I’m limited to either 6v or 7.4v for the input, so the Rx needs to work with that lower voltage.

I just realized that I needed the RGB functionality, so I just ordered this $4 one, I think the same as Dave B’s second unit:

http://www.aliexpress.com/item/1pcs-lot-DC-5V-24V-12A-17key-mini-RF-wireless-led-RGB-remote-Controller-with-4pin/2046611096.html

[Edit] OK, I ordered the one with the DIY buttons as well. They claim in the “specs” that it will work with 5v, but the device in the pic is labeled 12-24v. So, roll of the dice on that one. More cheap toys to play with though, I’ll use it somewhere eventually. (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-laughing.gif)

http://www.aliexpress.com/item/12A-DIY-RF-Mini-RGB-Controller-for-5050-3528-SMD-LED-Strip-Lights-Wireless-23-Dynamic/1000000666033.html

#20

Cliff - I’ll experiment with the lower voltage and the RGB unit over the weekend - should work at least down to 7 or so volts.

The Aliexpress unit is only one channel so you don’t have an option for reverse.

the Sears unit should work but you would have to add an H-Bridge and some other circuitry to get a speed controller out of it.

The 2nd Aliexpress unit is similar, but not identical to, the one I used - it does not appear to have the programmable buttons that I used to toggle direction - if you look closely at the remotes they are different - Here is a US supplier that has the right one

http://www.ebay.com/itm/SUPERNIGHT-RF-Wireless-Remote-Control-Dimmer-for-LED-RGB-Strip-Light-DC12V-24V-/331060664565?hash=item4d14c0d8f5:g:4I8AAOSw3mpXGc4K

dave