Hello Group,

I have an Arduino Mega with motor shield running DCC++. I also have a Raspberry Pi running Steve Todd's image. I have upgraded JMRI on the RPi to v4.16 and Java 1.8.0_65. I have the letter "D" as the connection prefix in the JMRI connection preferences.

I have a servo connected directly to the Mega with 5V, GND, and PIN15 for control. I checked the wiring and have a good 5V going to the servo. I have created an entry in the JMRI turnout table with hardware address 115 (now shows as DT115) and chose "BSOUTPUT" in the Feedback Mode chooser. I then added an output to the DCC++ base station configuration with Index 115 assigned to PIN 15.

I built a quick panel with DT115, and this seems to work OK as the icon moves when clicked, I see "closed/thrown" in the turnout table and I see the Output Cmd "Output ID: 115 low/high" in the DCC++ traffic monitor, but the servo does not move. I have tested the servo by itself using an Arduino servo sketch and it works fine.

What have I missed?

Thanks for your help,

Richard

开云体育

do you have enough current available??? The servo draws ~ 150mA when it's moving.?? You can turn it off once it's had a chance to stabilize.?? You may want to put the servo on an auxiliary power supply.

Hello Group,

I have an Arduino Mega with motor shield running DCC++. I also have a Raspberry Pi running Steve Todd's image. I have upgraded JMRI on the RPi to v4.16 and Java 1.8.0_65. I have the letter "D" as the connection prefix in the JMRI connection preferences.

I have a servo connected directly to the Mega with 5V, GND, and PIN15 for control. I checked the wiring and have a good 5V going to the servo. I have created an entry in the JMRI turnout table with hardware address 115 (now shows as DT115) and chose "BSOUTPUT" in the Feedback Mode chooser. I then added an output to the DCC++ base station configuration with Index 115 assigned to PIN 15.

I built a quick panel with DT115, and this seems to work OK as the icon moves when clicked, I see "closed/thrown" in the turnout table and I see the Output Cmd "Output ID: 115 low/high" in the DCC++ traffic monitor, but the servo does not move. I have tested the servo by itself using an Arduino servo sketch and it works fine.

What have I missed?

Thanks for your help,

Richard

-- 
Seth Neumann
Mountain View, CA

Hi,

Are you sure that your servo is compatible with DCC++? A standard RC servo requires a pulse width modulated signal, which the arduino servo library will generate, if that's what you have used in your test sketch. ?I'm possibly wrong here but I suspect the DCC++ code just puts out a logic high or low depending on the turnout setting, which won't drive a standard RC servo.

Regards

Paul

Thanks Seth,

I thought of this too, but was led to believe that you could run one servo directly connected to the Arduino's 5V supply and there would be enough current. Two or more … yes, a separate supply is required.

I have checked the voltage to the servo and have a full 5V.

Richard

Thanks Paul,

I started this effort by reading the following section on the JMRI site …?

If I understand correctly, I should be able to run one servo directly connected to the Arduino's 5V, GND and one digital port (mine is connected to port 7). Of the three methods available with the DCC++ sketch, only the third method using the base station "Output" approach should work. This is what I have done, and everything looks great in JMRI, but the servo never moves.

But I get your concern about the PWM. As I watch the DCC++ traffic monitor I see only a "Low" then "High" state for the JMRI turnout. And when I hold the servo next to my ear, I hear a "click" when I send the command in JMRI to go "closed" or "thrown".

Is there any way I can overcome this in the DCC++ sketch?

Richard

Hi Richard,

I've not used the DCC++ base station, although I've experimented with using the JMRI interface in conjunction with my own sketch. ?If there's a specialist forum for DCC++ you may get a better informed response there. ?Having said that I downloaded the base station sketch some time ago, which I assume you must have done in order to load it on to your mega. ?The code in Outputs.ccp appears to do a digital write to the output pin - line 85 but this may not be the latest version. ?If so it won't drive an RC servo. ?I've also used the standard Arduino servo library to successfully drive a servo, but on a non model railway related project. ?It may be possible to add the servo library to DCC++. ?It partly depends on your confidence level. ?Also I suspect both the DCC++ code and servo code do 'clever things' with the Arduino timers. ?There's potential for conflict if they are both trying to use the same timer.

Paul

I had a similar problem with an Arduino based servo for turnouts; the servo was only getting a shot of current instead of a significant length of current to move the servo.? You might check how long the current is applied to the servo.

Ken Moordigian
Jackson Livery
818-522-4292

Yes, I am trying run this on the same Arduino Mega that is running the DCC++ code. I just assumed that the DCC++ base station code, when configured for the outputs would handle one servo.

Did I assume incorrectly?

Thanks Ken,

This sounds like the issue I am seeing ...

So today I am trying a different approach. Rather than connect the servo to the Arduino Mega with the DCC++ sketch, I have ordered a Pi Servo pHAT for the Raspberry Pi that is running JMRI. This $10.95 product has 16 channels that allow for direct connection and management of 16 servos. Here is information on how it works:



Has anyone used a this product, or something similar? I am assuming I will be able to configure and operate this within the JMRI environment.

Richard

Just to add another view (which perhaps is an extension of what Richard will soon find with his Pi Servo pHAT approach) ...

I use DCC++ on an Arduino Mega with motor shield to command the locos on my small G-scale garden railway.? (It's connected to an iMac running JMRI and I use the iThrottle app to give me a wifi roving throttle? The Mega gets its power over USB from the iMac;? the motor shield has a separate 20V DC input to pass on to the rails.)

Quite separately, I have an ESP32 chip loaded with a modification from 2 sets of Rui Santos's code to set up a wifi server (search for ESP32 wifi server on youTube to find one video on creating a web server with buttons and one for servo control with a slider). My version provides a webpage of buttons to any connected client (such as an iPhone).? The client sends a web request of the form 192.168.55..1/?NN on my local network.? The ESP32 wifi server picks out the NN and recognises this as a request to switch a particular point/turnout servo, connected to a pin on the ESP32.? (I have 5 servos but it could support more.)? Note (1) that the ESP (and from there the servos) is powered from a 5V supply from a phone charger brick, and not from the DCC++ power supply - it's the sort of thing that you can use to recharge your phone when you're out and about and (2) the ESP32 can either send a single command to a servo to say move straight to position x, or a sequence of commands to move the servo incrementally to its end position to produce a smoother point change.

All works fine.? The only problem is I have two separate interfaces to play with - one to JMRI and one to the ESP32 - so tend to have to have both an iPhone (to the ESP32) and iPad (to WiThrottle) to hand, which is cumbersome.

Hence, I'm looking for an easy way for WiThrottle/JMRI to instruct the ESP32 to do something.

Maybe I can modify Outputs.cpp in the Arduino code to call the ESP32 webpage...? (Is there an HTTP library that might support this?)
Maybe the ESP32 will work with one of the DCCInterface.com products mentioned on the? page given by fcot2002 earlier (note the link there had a mistake in it).
If anyone has tried either of these things, please let me know with some details.
I'll write again if I get anywhere.

Regards,

Les

(I’ve kept all the below for context, mostly because I don’t understand it enough to quote just part of it)

Could you create a USB connection to the ESP32 chip and then use communications to transfer turnout commands?

Bob

On Jul 25, 2019, at 8:42 AM, les@... wrote:

Just to add another view (which perhaps is an extension of what Richard will soon find with his Pi Servo pHAT approach) ...

I use DCC++ on an Arduino Mega with motor shield to command the locos on my small G-scale garden railway. (It's connected to an iMac running JMRI and I use the iThrottle app to give me a wifi roving throttle The Mega gets its power over USB from the iMac; the motor shield has a separate 20V DC input to pass on to the rails.)

Quite separately, I have an ESP32 chip loaded with a modification from 2 sets of Rui Santos's code to set up a wifi server (search for ESP32 wifi server on youTube to find one video on creating a web server with buttons and one for servo control with a slider). My version provides a webpage of buttons to any connected client (such as an iPhone). The client sends a web request of the form 192.168.55..1/?NN on my local network. The ESP32 wifi server picks out the NN and recognises this as a request to switch a particular point/turnout servo, connected to a pin on the ESP32. (I have 5 servos but it could support more.) Note (1) that the ESP (and from there the servos) is powered from a 5V supply from a phone charger brick, and not from the DCC++ power supply - it's the sort of thing that you can use to recharge your phone when you're out and about and (2) the ESP32 can either send a single command to a servo to say move straight to position x, or a sequence of commands to move the servo incrementally to its end position to produce a smoother point change.

All works fine. The only problem is I have two separate interfaces to play with - one to JMRI and one to the ESP32 - so tend to have to have both an iPhone (to the ESP32) and iPad (to WiThrottle) to hand, which is cumbersome.

Hence, I'm looking for an easy way for WiThrottle/JMRI to instruct the ESP32 to do something.

Maybe I can modify Outputs.cpp in the Arduino code to call the ESP32 webpage... (Is there an HTTP library that might support this?)
Maybe the ESP32 will work with one of the DCCInterface.com products mentioned on the page given by fcot2002 earlier (note the link there had a mistake in it).
If anyone has tried either of these things, please let me know with some details.
I'll write again if I get anywhere.

Regards,

Les

--
Bob Jacobsen
rgj1927@...

On Thu, Jul 25, 2019 at 04:42 PM, les b49 wrote:

Hence, I'm looking for an easy way for WiThrottle/JMRI to instruct the ESP32 to do something

Have a look at MQTT. ?The JMRI implementation of this is described and supports turnouts. ?You will need to run a broker, but your PI should be able to run . ? I'd be surprised if there wasn't some MQTT client implementation available for the ESP32 as it's all about IOT and all the connections can be wireless as long as your garden railway is in range of a wifi router.

Paul

On Fri, Jul 26, 2019 at 11:41 AM, <paul@...> wrote:

PI

Sorry fingers out of control. ?Should be iMac! ?(or almost anything you can run JMRI on!)

Paul

Thank you, Bob & Paul. ?There's just so much to learn about JMRI (and then all the other bits of software it can interact with...)

Like much of Europe & the US at the moment, a heatwave here means I'm spending most time outside rather than at the computer, so it'll take me a little while to try the 2 suggestions out. ?But just a couple of comments:

Bob: ?At present, my iMac, Arduino & motor shield are in my office. ?A 5m USB cable currently runs from the motor shield there to the rails outside. ?The USB connection on the ESP32 (driving the servos) is taken up by the power supply from the 5v "Phone charging" battery. ?I could try using a different 5v source for the ESP32 connected directly to a voltage in on the ESP32 and so free up its USB connection to take input from motor shield as you suggest.

Paul: ?Yes, the ESP32 outside is on the house wifi - as are the iMac running JMRI and the iPhone running the WiThrottle app. ?Your suggestion looks feasible and I will try it in due course, but, if possible, I'd prefer not to have to introduce even more s/w elements to the system or interfaces between them, like MQTT and mosquito. ?We'll see...

Best regards,
Les

Richard,

Hi, Jason,

As I mentioned in my earlier post above (162059), I've got Arduino code that runs on an ESP32 chip, that creates a wifi server and then responds to client requests by switching servos on points. I think the ESP could support 16 servos as you want, but I'd have to check. ?The HiLetGo ESP I use is ?8.14 on Amazon and cheaper off AliExpress. ?Is that worth considering? ?I'm happy to share the code. ?(I don't know the RPi so don't know if Arduino sketches will run off it.)?

(I'm a programmer from the 70s whose now having fun but struggling to learn electronics in my retirement...)

Regards,
Les

Sorry, that should have referenced post 162049.