# Curiosity: Home Made DCC Booster



## wvgca

Snow is starting to come, time for toys and projects ..
I was thinking about making some kind of DCC booster, I personally don't need one right now, but I may later on ...

Design Criteria;
Universal hookup to most brands of DCC systems
Low Construction parts costs
Adjustable power output levels
Over current protection
Visible power usage / output indicators
Standard components
Usable as multiple booster arrays
Minimum 3A output capability

At this point looking for and needs and /or wants in final product ..
thanks


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## gunrunnerjohn

Does it work with TMCC? 

Just kidding, looking forward to what you come up with.


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## wvgca

gunrunnerjohn said:


> Does it work with TMCC?
> 
> Just kidding, looking forward to what you come up with.



No idea how TMCC works...
but if it's a variable square wave like standard DCC, all I'm looking at is taking the signal, and just cranking the power up , as far as I know O scale takes a lot more ..


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## RT_Coker

I would add a cheap DCC-decoder for remote control.
Bob


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## Lemonhawk

There are Arduino projects that make DCC command stations. I think they even have a shield PC board for it. This link is for a Speedometer http://arduinotronics.blogspot.com/ 
but I think it also points to where more DCC projects are. They have Arduino DCC libraries and I think the DCC system just uses a H driver module.


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## wvgca

Lemonhawk said:


> There are Arduino projects that make DCC command stations. I think they even have a shield PC board for it. This link is for a Speedometer http://arduinotronics.blogspot.com/
> but I think it also points to where more DCC projects are. They have Arduino DCC libraries and I think the DCC system just uses a H driver module.


I already have an Arduino running DCC++, and it works well ..
I also found last night a project from a fellow by the name of Dave Bodnar that looks like it will work for my purpose, and will probably build on his previous work ..the H-bridge in that one is rated for 43A max, should be enough?


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## Lemonhawk

43 Amps - just how steep is that logging RR. Maybe you just switched scales and joined GRJ in O gauge, don't his engines require 43 amps?


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## wvgca

apparantly the H-bridge has that capability ..the idea is to have a range of 3 to maybe 10A for output, the BTS7960B is only ten bucks, same as much smaller ones, and same basic hookup wiring ...
it's good to have 'just a little' extra


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## wvgca

RT_Coker said:


> I would add a cheap DCC-decoder for remote control.
> Bob



sorry .. I don't understand what you mean?
remote control for the booster?


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## RT_Coker

wvgca said:


> sorry .. I don't understand what you mean?
> remote control for the booster?


Yes, control the booster, booster-output-on-off and three-optional-on-off-outputs (lights or ?). Maybe shutdown-trip-current with the motor-control. Power DCC-decoder from booster-DCC-input-signal.
Bob


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## wvgca

Spent a couple hours tonight, got the schematic and preliminary board done .. uploaded to OSHpark as shared, cost of PCB is $34 / for three


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## gunrunnerjohn

Big board, I suspect you could have compressed it a little. 

What layout program is this done in?


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## wvgca

didn't try to squeeze it much, the image is from the OSHpark rendering of the Eagle BRD file ..no smd's at all ..traces are pretty wide so that it could be routed just for single if needed ..


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## gunrunnerjohn

I noticed it was all thru-hole, that will make it easy to slap together.


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## wvgca

gunrunnerjohn said:


> I noticed it was all thru-hole, that will make it easy to slap together.


It wasn't intended as a production / resale project, more as a to be shared project that can easily be assembled by end user ..pretty low cost, Arduino mini pro, and a ten dollar H-bridge ..two dollar 1602 LCD display .. I made a place on the pcb for the output amperage adjust, but could easily be panel mounted instead ..will need a input DC supply maybe 15V at 3 to twenty five amp board ,logic power is off input DCC signal


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## crusader27529

wvgca said:


> Spent a couple hours tonight, got the schematic and preliminary board done .. uploaded to OSHpark as shared, cost of PCB is $34 / for three
> 
> View attachment 253569


I noticed that the layout is for the Arduino PRO (Mini or Micro....I get confused with their names) has the extra analog pin placement for the 'old' design. Most of the newer stuff has those pins in different places, so getting the correct part can be problematic.

For those reasons, all my designs now is the Arduino NANO, which has well defined pinouts that do not change depending on who's version of the board you buy.

Having said that, if you don't ever need to use the extra analog pins, simply not using the connections (no pin connection) resolves the problem. I tend to use the extra analog pins for GPIO, so I expect all of them to be available.


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## gunrunnerjohn

I noticed the same thing when I looked at the Arduino Pro mini, I bought two and they had different pinouts. I like the NANO anyway, so it was easy to abandon the other one.


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## wvgca

I may have to re-do with something other than the pro mini ...merely because I didn't take into consideration that a seperate usb port would be needed on that processor board to upload the code .. I have it, but for others it would be 'once used' cost addon ..sigh..


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## Lemonhawk

I just got a couple of NANO's along with a servo shields today. I have a servo and a pot connected up and the servo turns as I turn the pot. These things are fun to play with. I have Mega2560's, ProMini's and now Nano's. The Mega and Nano have built in USB, lot easier to deal with. If you can wait for China Post, the Nano's are less than $3 in single quantities or $4 with the headers soldered.


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## wvgca

Lemonhawk said:


> The Mega and Nano have built in USB, lot easier to deal with. If you can wait for China Post, the Nano's are less than $3 in single quantities or $4 with the headers soldered.


Well, bit the bullet and ordered a couple of nano's, under six bucks ..gives me time to re-do the schematic / pcb ..it will be easier to load the code with an integral usb port ..
project on hold for a while ..oops 

Still have other projects on the go, so won't be drinking coffee all day anyways, plus have to shut the farm down for the winter..


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## crusader27529

wvgca said:


> Well, bit the bullet and ordered a couple of nano's, under six bucks ..gives me time to re-do the schematic / pcb ..it will be easier to load the code with an integral usb port ..
> project on hold for a while ..oops
> 
> Still have other projects on the go, so won't be drinking coffee all day anyways, plus have to shut the farm down for the winter..



Using the NANO has another advantage over the PRO Mini.....the serial interface us always available for monitor and/or diagnostic messages. But the way you setup the pcb, the interface isn't available if the board is directly soldered unless you supply secondary connectors for it.

Obviously, you connect to the LCD using a serial/SPI connection. I'm not a fan of SPI because most of my designs are timing critical, and the delays in the SPI library for LCD can be significant without modifying the libraries.

Anyway, I look forward to your finished design.....will you publish the schematic along with the code?


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## wvgca

crusader27529 said:


> Anyway, I look forward to your finished design.....will you publish the schematic along with the code?



here is preliminary schematic... top left is DCC signal stripper, 
middle left is logic power, that can be taken from external PSU instead, right is Pro Mini, will re-do for Nano, and bottom right is display, these two can be omitted if you don't want display or don't want external current limiting, and bottom left is H-bridge, which can be any compatible from 1A, user choice

pretty simple, can be reduced to signal stripper and H-bridge, should be suited to easy multiple booster configurations


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## crusader27529

wvgca said:


> here is preliminary schematic... top left is DCC signal stripper,
> middle left is logic power, that can be taken from external PSU instead, right is Pro Mini, will re-do for Nano, and bottom right is display, these two can be omitted if you don't want display or don't want external current limiting, and bottom left is H-bridge, which can be any compatible from 1A, user choice
> 
> pretty simple, can be reduced to signal stripper and H-bridge, should be suited to easy multiple booster configurations
> 
> View attachment 254169


The SV1 connector has an error....the SDA is tied to ground and the ground lead is driven by the Arduino.....seems they are reversed on the diagram.

Also, the IBT-2 headder requires VCC, and I don't see that connection. Do you have a functional prototype?

Otherwise, I more or less understand your design......will check further. If I'm incorrect (remember, we're both OLD), I apologize.


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## wvgca

crusader27529 said:


> The SV1 connector has an error....the SDA is tied to ground and the ground lead is driven by the Arduino.....seems they are reversed on the diagram.
> 
> Also, the IBT-2 headder requires VCC, and I don't see that connection. Do you have a functional prototype?
> 
> Otherwise, I more or less understand your design......will check further. If I'm incorrect (remember, we're both OLD), I apologize.


Caught those errors last night when I was re-doing it for the Nano...SDA/Ground reversed, need P7 of IBT-2 for VCC...
sharp eyes for an old guy ..

At this point, no prototype on my part yet, waiting on parts, basically I'm spending time trying to do the host PCB ahead ..
The IBT-2 is supposed to be rated for PWM input frequency up to 25kHZ, so 10kHZ should be fine.. and it's only a few dollars more than a 3A rated H-Bridge, the ones ordered were around twelve dollars ..
The code is on Dave Bodnar's site ..
http://trainelectronics.com/DCC_Arduino/DCC_Booster/index.htm


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## crusader27529

I use the IBT-2 for all my MD needs for DCC++.....it's very easy to interface especially for current monitoring.

I try to make most of my PCBs single sided so I can make them myself, so I usually use a 74LS04 inverter instead of a discrete transistor inverter, just for wiring simplicity.


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## wvgca

crusader27529 said:


> I try to make most of my PCBs single sided so I can make them myself, so I usually use a 74LS04 inverter instead of a discrete transistor inverter, just for wiring simplicity.


Makes sense, I built a small router a while ago for isolation routing on PCB's, works okay .. If Eagle had an auto place function that could reduce via count, I would use it, but it doesn't ..and my old version of Protel [99] doesn't either ..


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## crusader27529

wvgca said:


> Makes sense, I built a small router a while ago for isolation routing on PCB's, works okay .. If Eagle had an auto place function that could reduce via count, I would use it, but it doesn't ..and my old version of Protel [99] doesn't either ..


I tried to use Eagle years ago, but I just couldn't get into it, especially how they do parts libraries.

I use Kicad now, no limits on size or layers, but kind of techie. I haven't gotten the autorouter to work, or the 3-D stuff, but it works fine. Without real documentation, the learing curve is steep, and all the tutorials don't do what I want to do, AND are for earlier versions and therefore out of date.

But, it's free and meets my current needs, specifically for single sided boards.

I guess that I shouldn't complain about something that's free.


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## gunrunnerjohn

I had the same issue with Eagle, trying to define new parts was a royal PITA! That turned me off from using it as I end up defining parts for almost every project.

Diptrace has a pretty good autorouter, and you can tune it to the parameters you deem important.


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## wvgca

Fixed the errors, used the Nano instead of the Pro Mini, added reset button, redid the routing with larger trace widths and more clearance, board is smaller now, 2.6 x 2.0", OSHpark is $25.50 for three .. less money ..

current revised schematic, and board layout [top] , and BOM for your critique / perusal ..

















View attachment booster.BOM.txt


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## redman88

How does the boosted signal get back out to the track.


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## wvgca

redman88 said:


> How does the boosted signal get back out to the track.


On the host PCB there is an 8 pin connector [4x2] that goes to the IBT-2 H-Bridge, on the IBT-2 there is a 4 screw pin connector, two for DC power to the IBT-2, and two for DCC out to the track ..


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## redman88

Okay cool.


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## wvgca

Oops.. time for revision 3 on the PCB, for some reason I neglected to put in holes so the thing could actually be mounted normally,
And no parts in the mailbox so that I can actually see if it works as intended .. sigh ..


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## redman88

How about 4 holes around the edge so that the board can be mounted in a box.


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## wvgca

redman88 said:


> How about 4 holes around the edge so that the board can be mounted in a box.


probably, but might have to make the pcb a little bigger to allow for that, don't think there is enough to shift components around and re-route ..


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## redman88

wvgca said:


> probably, but might have to make the pcb a little bigger to allow for that, don't think there is enough to shift components around and re-route ..




Okay just a thought.


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## gunrunnerjohn

Sure there is, surface mount stuff, make it really small!


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## wvgca

gunrunnerjohn said:


> Sure there is, surface mount stuff, make it really small!



the booster gets through hole ,, much easier to toss together ..
I have another project going with a mux on QFP 38 .. 38 pins in 24mm of edge .. not looking forward to that, might actually have to buy a hot air station .. never really needed one before


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## gunrunnerjohn

As long as the pitch of the QFP pins isn't too tight, you can solder them. However, I personally stay away from them due to the fact that they're such a PITA to deal with. If the pitch gets down to .95mm, that's as low as I typically go. I made the mistake of using some parts with .065mm spacing, what a PITA to solder!


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## wvgca

okay, mounting holes added ...
link to PCB on OSHpark .. https://oshpark.com/shared_projects/N54QYihJ

If you have Eagle Layout Editor, 
View attachment booster - Copy.brd.txt


View attachment booster - Copy.sch.txt


Delete the .txt extension to use ...


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## redman88

Your awesome.


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## wvgca

redman88 said:


> Your awesome.



nah ... just bored ...
maybe I need a hobby??


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## Lemonhawk

The actual DCC signal doesn't even get into the Nano, so the actual "Booster" does not need it. Why not make the booster a little more multi-purpose and bring the DCC signal into the Nano so at some future time you could do something with it. You could have a stationary decoder in the Nano besides the current monitoring function. Of course you could replace the 16x2 LCD screen with a nice 2" color display and have a nice digital scope display of the DCC signal. Just trying to put all the Nano computing power to work! Weather looks like it taking a turn for the worst where you are - nice project for that cold winter day!


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## wvgca

Lemonhawk said:


> The actual DCC signal doesn't even get into the Nano, so the actual "Booster" does not need it.


Yep, all the Nano does is monitor current, with adjustable limit ..and display it as well .. no more ..

Probably the next step, sometime down the road, rather than adding, will be to reduce components .. just the DCC stripper along with a small, say 3A H-bridge with self limiting ..
with the result being a DCC booster than can be built from $25 , much much less than available commercial products ..


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## RT_Coker

wvgca said:


> Yep, all the Nano does is monitor current, with adjustable limit ..and display it as well .. no more ..


You might want to add an auto-reverse capability for the DCC-output-phase. It makes for an easier setup and can also be used for reverse-loops. This may require only code.
Bob


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## crusader27529

RT_Coker said:


> You might want to add an auto-reverse capability for the DCC-output-phase. It makes for an easier setup and can also be used for reverse-loops. This may require only code.
> Bob


Any reverser will require some hardware......even if it's just something to reverse the phase of the signal before it gets amplified, or maybe something on the output stage to do the reversal, but hardware in both cases.

Granted, the hardware isn't significant, but determining the difference between a real overload and one that would require a reversal isn't always simple or easy, specifically because of interaction with various command stations.


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## Lemonhawk

I think the reverser would only take and inverter, so the Nano would have to select inverted or not inverted to send to the H driver. Seems like this would make a great project, especially if the Nano can react fast enough on current detection!


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## wvgca

a quick look seems to show that it would require both additional hardware, and changes to the .ino sketch as well ..
As of now, the arduino does not control the DCC output in any way other than shutdown on current overload ..
to accomplish reversal would require either a solid state relay on the output, or a inverter on the input to the 2N2222 transistor that gives the proper PWM signal to the H-bridge .. plus code to let the Nano try to flip the output to see if a reversal would stop the overload, otherwise continue with shutdown


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## Lemonhawk

But at least the current in in the Nano and you don't need the DCC signal just the logic to invert or not invert form the Nano. Whether the Nano can detect and respond fast enough I don't know. I come from a programming area where you optimized the speed by where you put the instruction on the rotating disk memory so that you did not have to wait for the disk to rotate much to pick up the next instruction (DDA's) or in the case of the F14 you could not use 2-4 instruction loops as that would burnout the memory!


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## gunrunnerjohn

uP technology has come a long ways since you stored instructions on drums or disks and accessed them directly!  The current Arduino versions could respond in a few microseconds if programmed properly, and no memory burnout issues.


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## andiatbaden

*Question about capacitor*

Hello Warren,

thanks for the very good job :smilie_daumenpos:

I try to build the booster, but there is still one question left.

In the schematic file there are three capacitors:

C1 - 270 pf
C2 - 0,1 pf
C3 - 470 pf

C1 and C3 don't make any Problem to buy, but C2 with 0,1 pf is 
nowhere to buy. Is it possible that it is an 0,1uF capacitor?

Thanks for your answer!

Greetings from Germany

Andreas


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## wvgca

andiatbaden said:


> C1 - 270 pf
> C2 - 0,1 pf
> C3 - 470 pf
> 
> C1 and C3 don't make any Problem to buy, but C2 with 0,1 pf is
> nowhere to buy. Is it possible that it is an 0,1uF capacitor? /QUOTE]
> 
> its just a dcv decoupler / filter, anything similar will work...


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## andiatbaden

wvgca said:


> andiatbaden said:
> 
> 
> 
> C1 - 270 pf
> C2 - 0,1 pf
> C3 - 470 pf
> 
> C1 and C3 don't make any Problem to buy, but C2 with 0,1 pf is
> nowhere to buy. Is it possible that it is an 0,1uF capacitor? /QUOTE]
> 
> its just a dcv decoupler / filter, anything similar will work...
> 
> 
> 
> Hi Warren,
> 
> thank you for the quick reply.
> 
> So i can take a capacitor with 10 pf and it works?
> 
> Greetings from Germany
> 
> Andreas
Click to expand...


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## wvgca

any reasonable value will work ..
C2 is just for smoothening the input dc voltage to the 7805


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## andiatbaden

Hello Warren,

thank you, i will give it a try. Still one question left. I use the dcc++ central. How do i connect the central with on or more boosters? Is it possible to build a dcc++ plus "bus" with the output from the dcc++ central over two wires and connect the booster(s) to this "bus"?

Thank's a lot for your answer

Greetings from Germany

Andreas


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## wvgca

i used it with a dcc++ signal out, worked well, of you run more than one booster, make sure to get phase's lined up with a test light or similar ...


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## andiatbaden

Hello Warren,

thank you for your support.

Greetings from Germany

Andreas


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## crusader27529

Warren.....did you ever upload the code for this booster?? I can't find it if you did....or maybe Dave Bodner's code works on it?


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## wvgca

crusader27529 said:


> Warren.....did you ever upload the code for this booster?? I can't find it if you did....or maybe Dave Bodner's code works on it?



Either my code or Dave;s , same thing..
orgional is from Dave, all I did was the pcBoard ...


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## crusader27529

I'm working on a version of DCC++ that will work with up to 8 booster/power districts, but I'm having issues with cable lengths related to the current sense analog signals....since I was going to upgrade the design with a remote Arduino to do reverse loop stuff anyway, I've decide to use your/Dave's design to some degree.

My design uses RS-485 trancievers to extend the length that I can send the DCC(and the enable signal) across CAT5 cables, so I won't need the DCC stripper circuitry, or for that matter the onboard power supply, since the main PCB that runs the DCC++ code also powers the remote boards through the CAT5 cable.

My design also will be open source, both HW & SW, and has all the extraneous code that doesn't have anything to do with controlling locomotives stripped out of the code. I have enough room in the Arduino NANO for 40 locomotive slots to send DCC commands.

Anyway, thanks for getting me thinking to solve my problem. The current sense will just be a gross level voltage guaranteed to be interpreted by the DCC++ system as over current or not....


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## wvgca

Dave's design, as implemeted by me, just uses the nano for current limiting, and readout..
nothing more, pretty simple...and can be run in multi booster configuration as it gets its DCC signal off the first unit, in my case the factory one...delays are taken care of by the speed of the DCC switching portion...


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## crusader27529

The code required for a reversing implementation with an IBT-2 MD and an Arduino is very simple.....I'll send you the information and code as soon as I've finished debugging the HW & SW.

It does require an XOR HW function(74LS86 or a transistor implementation) to actually perform the phase reversal because the Arduino doesn't even see the DCC signal.


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## wvgca

another version is good for those who want a auto reverse style. i assume you would have a user adjustable percentage level adjustment for level phase switching ???

you are right that the arduino doesn't see the actual DCC signal, just the power output level ..


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## crusader27529

wvgca said:


> another version is good for those who want a auto reverse style. i assume you would have a user adjustable percentage level adjustment for level phase switching ???
> 
> you are right that the arduino doesn't see the actual DCC signal, just the power output level ..


Nope....I'll supply 2 digital input pins that select 3, 4, 5 or 6 amp limits......obviously, that can be changed. The phase reversal trigger is a short/overcurrent sense.....the phase is then reversed(with some minor logic) and if the short is resolved, no further action is required.

My design is made to work with my system, but obviously can be modified. AAMOF, my goal is to have one PCB work as a reversing module OR a non-reversing module by removing the Arduino NANO, and adding a few jumpers.....the design you're working from would require a NANO in all cases, where mine sends the current sense back to the 'main' DCC++ Arduino. That's where the minor logic does it's 'magic'. You'll see from the code.


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## wvgca

the nano is only 5 bucks or so, the board is a couple, and the IBT is 12 [canadian, even].. so it's not going to break the bank ..
pretty cheap actually, for a system that will give up to 43 amps [not tested by me] ..

a good deal


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## marsgd

Hello wvgca
DCC Booster Successful operation?


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## wvgca

yes, using 43A module


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## crusader27529

Well Warren, it's been winter for a while, and the farm is probably shut down, but I've seen no new projects from the frozen north wilderness of Canada for some time.

Cut the slack and engineer something!!!

Just kidding......I really enjoy your work....


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## wvgca

it's been pretty quiet here, focusing not so much on model train applications, rather spending the time on agricultural auto steer system, using a 055 icnlinometer right now, driven with an arduino nano for automatic sprayer section control, software is C++ mostly ..
just a different direction, still doing the remote temperature sensor on grain bins as time allows, going to 1 wire stuff mostly


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## Shdwdrgn

Just read through all seven page and wanted to put in my two-cents worth. Instead of using an arduino, what about an ATtiny85? Standard 8-pin DIP package so it will easily fit on a circuit board and can be reprogrammed in-circuit if you're not using the serial pins. Appears to have 10-bit analog inputs which obviously will detect a direct short, however this brings me to my second point... In other discussions about building an auto-reverser some folks have mentioned that it's not just a matter of detecting shorts, but also monitoring the slope to determine if you actually have a short or just some power-hungry caps being recharged. It seems like the circuit might be more reliable if you simply monitored the *rate* of current change and only switched on a really fast spike? Regardless, the ATtiny will run at 8Mhz so it's just as fast as some of the arduinos and will run the same code.


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## wvgca

Shdwdrgn said:


> J Instead of using an arduino, what about an ATtiny85? Regardless, the ATtiny will run at 8Mhz so it's just as fast as some of the arduinos and will run the same code.



so far it's just a pcb for dave's schematic... but definitely not ruling it out .... would make the board smaller, and probably a bit cheaper :appl:


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## jc286006

Hello Everyone 
If anyone still monitors this thread is X3 pinout
7531
8642
from left to right and top to bottom? since there are no markings on the pcb referencing which one is number 1,2 etc


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## wvgca

jc286006 said:


> since there are no markings on the pcb referencing which one is number 1,2 etc





if you mean D1 , D2, R1, R2 etc... those are in the silkscreen layer, which your pcb maker should have added for you ??


if not, they can be gotten from the schematic ..or from the image of the pcb ??


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## jc286006

I mean the X3 connector that goes to the motor driver board there are no markings to denote which one is #1 X3 hooks to rpwm pin1,lpwm pin2,R_en pin3,L_en pin4,R_S pin5,L_S pin6,VCC pin 7,GrN pin8 on the motor driver . the best i can tell X3 pin1 is the upper right pin on the board png on page 3 of this thread. I am assuming that the X3 pinout is 7531 on the top row and 8642 on the lower row. I have built the board hooked it up to the Dcc++ base station and to the 43 amp motor driver that Dave Bodnar uses, the LCD shows that it is functioning correctly amps can be adjusted, power is on, but when a loco is placed on the track and power applied to the high amp driver board the loco takes off at full throttle no matter what the throttle is set at 0-100 it acts like some of the connections between the X3 pins and the MD are not hooked up correctly. I dont want to start moving wires around and fry something. I have 23 boards to play with but dont want to be smokin an arduino or the board components


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## wvgca

ok ... that i don't remember, sorry .. i built one , but it's hidden on my layout .. i don't remember if i used a formed cable, or singles there ..
you will have to follow the schematic for pin locations ...


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## Joe-M

Good morning,
even when this 'discussuion' started more than 4 years ago, I have to tell something.
I am just building my layout and I have build five of this bossters. But when I took the first online I did not get a good DCC signal output. I have searched for the problem and I found tat the signal on X3-1 to my H-bridge was to weak. It just reached 1Vss while the signal on X3-2 was little above 4Vss. After searching a bit in the net I have found a scematic where the 6N137 has had a load resister about 330Ohms.

So I decided to put a 560Ohm resistor as R3 instead of the 4K7. This solved my problem.
This is just a hint for others who run into the same issue.

But at the end I would like to say thank you all for the effort you have put into that nice booster.


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