My Official DC Throttle Product Thread

[mmagliaro]

Okay, folks, here is what will be the official thread for any questions about my DC throttle project, and any consideration of building these for hire.
The most recent photos, and pricing are here:
https://www.therailwire.net/forum/index.php?topic=55335.msg769047#msg769047

Youtube video of it operating in a test on my workbench.

If anyone is interested... I need a guinea pig, er, beta tester... somebody other than myself. 
So if anyone actually decides to buy one of these, the first person who does
can have the throttle + receiver + remote for $200 instead of $335... in exchange, of course, for being willing to do some back-and-forth with me about things they might want to change, doing experiments I might ask for, testing refinements if there are any problems with it, and so on. 



In reply to the most recent questions...
I can build it using either the 433 MHz or 315 MHz frequency band.  These are the two for which inexpensive transmit/receive modules are readily available.   The wireless protocol is very simple.  It's just OOK (on-off-keying).  It's the sort of thing normally used for products like garage door openers, remote outdoor weather stations, and other consumer remote control devices that just have to send short  simple messages.  As it happens, controlling a train is pretty low-volume data sending.  It just has to send commands to change speed and direction, and they don't get sent very often.  So this scheme handles it well.

As for distance.  I just distance-tested it about as well as I can.  I rigged up a hand-held to be in "barrage mode", where it just keeps sending out speed commands ramping up and down from 0 to full, then back to 0 again, over and over, spaced apart by about 100 mSec.   ( I know... who changes speed every 1/10th of a second...)..  Anyway...

Through two walls from inside my train room, with the controller outside in the yard, reliable control distance is about 50 feet.  By 75 feet you get nothing, and somewhere in between, it starts getting spotty.

Line-of-Site: Throttle sitting on my deck, the hand-held controller out into the yard as far as I can go..
100 feet... and still working.  and I'm out of yard.   Since the receiver can be powered by a USB as well as a normal "train" power supply, I will try plugging it into the car dash and then just going far out down the street to see what the true maximum line-of-sight distance is.  But I think these distances are  realistic.

The two walls is not an insignificant thing to consider.  It has to work when people, benchwork, a wall, or who-knows-what gets in the way. 

----
Interference testing....  Because you can use more then one remote at a time with multiple throttles, and they are all on the same frequency, if two controllers send at the same time, the messages will not be received.  So all messages are sent multiple times for redundancy.  I tested it in the train room with two hand-helds running in that continuous "barrage" mode, while I ran an actual train with a third controller.  It seemed to work perfectly fine.

I would say if you really put 5 or 6 of these in one room, you might have problems.  But in that case, I would suggest building 3 of them for 433 MHz and 3 of them for 315 MHz.  That would cut the collision problem in half.

[Lemosteam]

HI Max, were you still considering a Radio Shack kit style offering?  If so what would be the cost?

[mmagliaro]

HI Max, were you still considering a Radio Shack kit style offering?  If so what would be the cost?

John,
I would consider it.  But consider all the complications that go with this.  This post is kind of long, but there is a lot to
think about if you really want to do this.

1.  I have written a whole assembly section with photos in the technical guide "book" I already wrote
good thing

2. But the assembly instructions definitely assume the reader has some understanding of electronic components to the level of knowing what a transistor, resistor, capacitor, etc, are, and is able to read markings to choose the correct part  and insert it the right way.  It also assumes they have basic test equipment like a multi-tester and they know how to measure current, resistance, and voltage with it.  For one aspect of it (the pulse generator), if you want to include the self-contained pulse generator so that the throttle can be powered from a DC source, you need an oscilloscope to set it correctly (you can avoid that if you use the simpler AC-based pulse generator).  So it's not quite as simple as a Radio Shack or "Heathkit" level of instructions, where they would tell you, part-by-part, "Insert resistor R22 - the half watt, 1k, brown-black-red".  I tended to show a photo or drawing of the PCB with certain components circled, and instructions that say, "Insert the component shown".  It assumes you can read component markings and stripes.
not-so-good, but maybe tolerable

3.The hours involved in just collecting up all the parts and putting them in clearly labeled little packages, would probably take me 1/2 the time it took me to build it.    And I have to consider that whoever does this, well-skilled or not, will probably require support and time from me as they go.   I certainly wouldn't be surprised if I make a few mistakes packing and labeling it all, especially the first few times.  I don't think I can make up a kit and support the builder much cheaper than building it myself.   If the total throttle+receiver+transmitter costs $335, then maybe something like $300 for a kit?   There are simply a lot of parts to this, and good electronic parts ain't cheap.
Would that be acceptable?

4. My liablity.  What happens if somebody tries to build and can't make it work, or they blow up components along the way? 
I could not possibly take on the expense and time of replacing parts and repairing failed assemblies  
If you build it, ya bought it.

After those "discouraging words"... if you still want to try this...

Here's a sample photo with instructions from the assembly section of the manual.   You can judge from this if it's something you think would be adequate for you to follow.  Note, all the parts are clearly labeled in the silk screening on the board.  Some steps have more detail than this, but this is typical.

"Begin by installing the components on the main board that are common to both pulse generators (Figure 61)."


                      Figure 61: Initial Pulse Components

[mmagliaro]

John,
One more thing.  If you want to look at the full-blown technical guide and decide if it looks complete enough for you to attempt this yourself, send me a PM or email, and I will gladly email you the whole thing to read.