Thursday, August 01, 2013

Evaluation of Deltang radio control system

I've been experimenting for some time with various options for the radio control of my battery powered locos (see How I constructed an 0-6-2T, How I constructed an IP Engineering diesel loco and How I constructed a two car rail motor). I've been trying to find the most cost effective way of controlling them which balances cost against operability.

My first venture into cheap radio control was through the use of a remote dimmer for LED lighting which uses a small keyfob (see Using an LED dimmer for radio control of a loco). Whilst this approach is very inexpensive (overall cost around £5), it does have limitations. At present, I have not found a way of reversing the loco remotely (though this could be done with another keyfob controller) and the control is not particularly smooth.

My second approach was to make use of a very inexpensive 2.4 gHz transmitter, a receiver and a controller designed for use with garden railways (see Evaluating a low cost transmitter for garden railway use). This provided a good level of control but although the transmitter was less than £5, the receivers cost around £10 and the controllers range in price from £30 to £75. A transmitter, receiver and controller is needed for each loco. A disadvantage is that the transmitters are primarily designed for aeroplanes or helicopters and hence the joysticks need to be held in position to keep the loco moving (though the transmitter can be turned off once the cruise speed has been set).

The Deltang transmitter

What attracted me to the Deltang system was firstly that up to twelve locos can be controlled from a single transmitter which has been designed specifically for use with railway locomotives. The transmitter has a control knob an inertia control knob and a loco selector switch. The second attraction was the cost. Once one transmitter has been bought (for around £60 - or as a kit for £25), there is no need to buy another. Furthermore, the combined receiver/controllers cost just under £30.

The receiver/controller

The receiver/controllers are very small in size, being intended for use in 00 or even N gauge locos as well as 16mm and G scale locos. Despite their size, they will handle up to 1.5 amps, which is fine for most of the smaller locos used on garden railways. The designer is planning a version which can handle more amps.

There are four wires attached to the receiver - black and red are for the battery supply (from 3 volts to 16 volts) and the two brown wires connect to the motor.

I use a connector block to make the removal of motor controllers easier, but if you are pushed for space, the receiver/controller could be hard-wired in.

There are several other outputs which can be used - but as yet I have not explored them. These include:
  • Servo control - eg for remote uncoupling
  • Forward lights
  • Reverse lights

Binding

Binding is extremely easy. Firstly the receiver is switched on. There is a tiny LED which indicates the state of the receiver. Initially, it flashes every two seconds as it hunts for a signal from the transmitter. If it doesn't detect a signal after 20 seconds it goes into bind mode which is indicated by a rapid flashing of the LED.

To bind the transmitter, firstly the loco selector switch is clicked to the desired position (eg loco no. 2), the bind button is held down and then the transmitter is switched on - then the bind button can be released. The light on the transmitter flashes to show it is in bind mode and if all is well the LED on the receiver flashes in unison with it. 

After a few seconds the lights on both the transmitter and receiver stop flashing and show a steady light indicating the binding has been successful. The instructions suggest that it may take more than one attempt to bind successfully, but my experience so far has been that binding was OK first time.

Operation

Once each loco has been bound to a particular channel on the selector switch it will only respond when the switch is in that position. Speed and direction are controlled with the large knob at the lower end of the transmitter. I have found that very fine control is possible, though this is dependent on the responsiveness of the loco mechanism. Once a cruise speed has been set for a particular loco, the selector switch can be turned to control a different loco. The first loco will continue on its speed setting until the selector switch is turned back to select that loco again.

The default is for the receiver/controllers to bring the  loco to a controlled stop if the transmitter signal is lost (eg if the transmitter goes out of range or is switched off). However, this default setting can be reprogrammed to enable 'cruise control', whereby the motor will continue running on its setting if the signal is lost.

The inertia control is quite handy. I tend to set it to just under the half way mark. This provides a smooth start and stop and so is much more gentle on the loco's mechanism. The smoothness of the start and stop is dependent on the particular mechanism of the loco. One of my locos (with an LGB motor block) responds very well while another (with an adapted IP Engineering motor and gearbox) is less smooth. However, this mechanism is quite stiff and so may improve once it is run-in.

Programming the receiver

Several settings on the receiver/controller can be reset from the defaults by the user with a standard DSM2 transmitter or with Deltang's own programmer module. I have not explored the settings fully as yet but the following are just some of the settings which can be adjusted:
  • Whether the motor will respond to the single speed/direction knob or a combination of the speed knob and the reverse switch
  • The start and maximum speed setting for each loco
  • The PWM frequency. The default is 60Hz but it can be set to 250Hz. There are also options to set for 2kHz and 16kHz but only for low power, low voltage motors.
  • The time before the receiver goes to sleep if no signal is received
  • Failsafe or cruise (ie whether the loco stops or continues when the transmitter is switch off or the signal is lost)
  • Servo settings (eg for remote uncoupling)
  • Output settings (eg for flashing lights or the momentary or latched switching of accessories

Evaluation

 I have so far tested the system on three locos and a bare LGB motor block. The smoothest and most responsive control is with the LGB motor blocks. The railbus, which has now been equipped with an MFA Como planetary gearbox motor and bevel gears is also very responsive. An IP Engineering diesel loco which has had its gearbox replaced with a homebuilt gearbox is somewhat unreliable. Mostly it responds reasonably well but occasionally it has difficulties starting off in reverse. This may have something to do with the mechanism or may be a feature of that particular motor or may have something to do with the metal body of the loco (my others have plastic bodies). I need to do more extensive testing to determine where the problem lies.

All my locos are powered with 12 volt battery packs. I did find, when trying to power the bare LGB motor block with a 6 volt battery pack that it experienced problems at the lower speeds - sometimes the motor would hum and struggle to get started, even when the speed knob was turned up. This may have something to do with the motor originally being designed to run off 24 volts, though.

I have also tested the system with a small loco designed to run off 3-6 volts. At 3v the system was unreliable, However, at 4.5v there was a marked difference. The motor was very responsive and controllable. The limitation of using the low voltage was that the range seem to be considerably more restricted and the signal more prone to interference from foliage etc. This video gives a brief overview of the system in 4.5 volts (please forgive the crudity of the loco - it was hurriedly built for this test).

On 12 volts or more, the maximum range of the system is said to be around 40 metres in ideal conditions. I have tested the system (with 12 volts) in my garden and found it responds without difficulty from one end of my garden to the other - approx 25m distant. I have not experienced any difficulty with interference from foliage or buildings - at one point my railway runs behind two sheds which are full of metal objects (mower, garden tools, trailer tent, etc.) and so far there have been no drop-outs in the signal. The receivers do not seem to draw too much current. I have accidentally left them on for several hours without any subsequent appreciable loss of battery power.

Overall, I have been very impressed with the system so far. I need to do more extensive and intensive testing, but the units seem robust despite their size. I think the plan to introduce a receiver with a higher amperage rating is a good move. Although most of my locos draw around 1 amp, I would imagine there will be occasions when it would be useful to have a higher ceiling. Price-wise, there seems little to beat this tailor-made system for the radio control of trains at present

 Video Evaluation


Update - May 2016

Since writing this blog entry, I have started producing my own versions of Deltang transmitters. See  http://rctrains.co.uk for more information.





14 comments:

Greenman Belg said...

Hi Rik, seems like a very simple system. Thanks for the video and all the other stuff you blog about. Regards JD.

Ge Rik said...

Thanks JD
I'm in the process of writing another blog posting about Deltang r/c kit. Since I wrote this post I have gained more experience and some of the equipment has been updated.

I'm glad you've been finding the blog interesting. My intention has always been to share with others what I've been up to in the hope that some of it might be useful - even if only to say "Well I wouldn't do it like that myself."

Rik

Anonymous said...

Hello Rik,

I stumbled upon your YouTube video by accident and was very impressed because I want to do the same thing here in the States with a very small loco in G-scale.

Can you tell me where to buy the 12 volt battery's ?

Thanh You.

Ge Rik said...

Hi Anon
I get them from China via eBay. Search for 12v CCTV battery. The ones I've used come in a blue wrapper. Hope that helps.

Dave Bowden said...

Hi Rik
Having read your blog on RC control with the Deltang system, which was excellent and informative.

I believe I require a Rx65-22-S (is this the combined ecs and rx you spoke of ) I shall also purchase the Tx-22 as a kit to complement the setup.

This will then only leave the batteries to source with some switches as I wish to retain the option of using track power as well.
The Loco will be a G1 GWR 45xx (sang Cheng)

Regards
Dave

Dave Bowden said...

Hi Rik

Can you confirm that the Deltang Rx65-22-s is a combined ecs and Rx (s for the terminal option)

Regards
Dave

Ge Rik said...

Hi Dave
Yes. That's right. Just four wires needed -two for the input power supply and two output to the motor. Just connect it up, bind it to the transmitter and away you go.
Rik

Dave Bowden said...

Hi Rik

I now have the Tx22 kit & the Rx65b arrived a couple of days ago, could I ask what rating the auto switch you use is, I have one but mine is a 2.2A version.

Bearing in mind I shall be running this on G1 locos. These have 24v motors but do run perfectly ok on 12volts. I originally was going to put the Rx and batteries in the loco but having seen a demo at the weekend of using a box van behind the loco for the batteries 12x 2150mAh and the Rx and switches, you can then put the roof on and away you go.

For more than one running loco you will need two box vans and all the kit that goes in it.

Any comments would be welcome please

Regards
Dave

Ge Rik said...

Hi Dave
Sorry about the delay in responding - only just seen your comment.
I use a 1.6A auto fuse - basically because that's the one which Brian Jones supplies with his gear. A friend of mine uses 2.2A quite successfully. The main thing they are protecting against is short circuit so the value is not too critical.

I considered using a trail van - one van can serve several locos, so it's quite efficient use of resources. However, I tend to run mainly end-to-end and so run the locos around their trains. Without a turntable, the trail van would end up at the wrong end of the loco. So in the end, I squeeze batteries into my locos where I can, which is mainly why I use li-ion.

Rik

Dave Bowden said...

Hi Rik

I believe your locos are of a much lower voltage than my G1 locos with their 24v motors. I shall initially be using 7 dayshop.com Good to Go low discharge batteries as these have only cost me £4.24 per 4 pack and I can charge them with a standard charger not one of those smart delta V pulse chargers. Might be a different matter if I was using a pack of 12 Strikalite shrink wrapped ones.

Dave

Dave Bowden said...

Hi Rik

How come you have a post listed as of the 1st of September?

Dave

Ge Rik said...

Hi Dave
Coincidentally, I'm just awaiting delivery of four LSD PP3 batteries from them for my Deltang transmitters. My locos are 12v or less, so I can get away with smaller battery packs - in fact one of my smallest locos is powered by just one 18650 li-ion cell.

I always keep the introductory post 'in the future' so that it always appears first. Blog entries are presented in chronological order. Reminds me, I'll soon have to do its annual up-date.

Rik

Dave Bowden said...

Hi Rik
Did you build the tx22 from a kit or buy it ready made?

Dave

Dave@davesmodels.co.uk

Ge Rik said...

Hi Dave
I bought it ready made. When I first started out, I lacked confidence and so went for what seemed the easier option. I have since made a Tx21 and a Tx27 from kits and would feel more than happy to now construct a Tx22 - though there are a few more components to solder together with the selector switch. However, in the main the soldering required is not too fiddly - basically soldering leads from one connection to another - and adding a few resistors.

Rik