For a DCC++ using the Arduino Motor Shield Rev 3, will the shield burn out when you short the rails for a couple minutes? Reason I ask is sometimes when talking to people at a train show, I have someone come up and say the train stopped over there, and discover a derailed truck with a shorted wheel at a turnout. If you catch it soon enough, the wheel did not get hot and melt, and your loco is OK. Removing the short automatically restored power, and trains resume. Would this situation take out the Arduino Motor Shield Rev 3 or would it also continue operation? Alternately, is there a more robust motor shield recommended, or is a circuit breaker board always recommended to be used?
the basic motor shield for DCC++ has current sensing so it will shut down. the polou shield does also (i believe). i have seen others use a max471 to perform the current measurement for other boards.
The motor shield itself wont ever cut power on its own. As said the DCC++ code on the base station has overload protection that will cut power if it has a current sense hooked up to A0. Most motor shields have but you can also do with a max471 or similar as mentioned I always put a circuit break to my track in addition just in case. Several good commercial ones out there psx, nce, etc.
Sorry I'm late to the discussion. Your setup with the Arduino motor board handles short detection out of the box. You can find a video where Greg drops a nail or something on the tracks. DCC++ polls the track current and shuts off power to the motor board. You have to reset though in that version. We are updating the project and calling it DCC++ EX. We added Auto restart when the short is removed among other things.
I just received a ZYLtech Mega 2560 R3 and a Deek-Robot Motor Shield for my DCC++ venture, would these work with DCC++ EX? These are as close to real Arduino clones as I could find for cheap.
Should work just fine. I used an Elegoo Mega clone for about $8 and a Deek-Robot board on a test system.
I don't know about the Mega , but I do know the Deek Robot motor shield does work on DCC++, I have it set up now for the past several years ..
What about the larger amperage motor boards from Pololu? I happen to have a Pololu 2517 which is specified up to 30V and 22A continuous. Could I use this board in place of the 33926? Dave
Hi All, I'm looking for a motor shield for garden scale. I purchased a Pololu MC33926 and got it working right up to the point we tried to use our reverse loop. It immediately faults before the reverser gets a chance to act. I decided big is better and got a Pololu 5019 but after I got it, I discovered there can be up to 285us delay in transitioning direction (INA td-on), way too slow for DCC. I thought about getting an Arduino shield as it won't have the auto shutdown in the chip but 2 amps isn't much current. Just noticed the Arduino shield handles up to 12v. So much for that. Does anyone have a recommendation? Thanks, Steve
Well, the biggest reason the Arduino/Deek-Robot motor boards say they are limited to 12V is that greater than that is because it will fry the Uno/Mega, etc. if you have more than 12V going into the motor board and don't cut the Vin trace. Plenty of people are running them at 18V and even 24V. As long as the capacitors are the 35V ones. I think the can cap is 25V. You might be able to find people running the the voltage you need who can comment on that. Here are some links for you: https://www.locoduino.org/spip.php?article187 http://trainelectronics.com/DCC_Arduino/DCC++/ https://model-railroad-hobbyist.com/node/35753 and related: https://www.locoduino.org/spip.php?article253 The locduino sites are in French, but google automatically translates them extremely well. Thought I have absolutely no need for it, I have really wanted to build the setup shown in last link. I could power a real railroad. DCC++ EX has support for the LMD18200 and BTS7960B based boards. There may be jumpers that need removing, at least on some of the LMD18200 boards since the 5V regulator is rated for only 12V. You can also keep whatever board you started with and use it to power your programming track and then use the higher power device to run OPS. Keep in mind current sense and how you want to accomplish that. The Locoduino folks like the MAX471. I've noticed they have used them even on boards that have current sense.
Thanks much for the reply. I've ordered a BTS7960B based board and a few parts to to deal with the PWM differences and I'll give that a go. I like what they did at train electronics with the booster approach. I'll keep what I have and add this to it.
