geoff

Dave, if you mean two class 20s coupled nose to nose just set one to run forwards and the other to run in reverse and , on my DT 402, press "MU" and + and the two locos will run together in which ever direction you choose. I believe Digitrax calls that basic consisting. Geoff

This seems to be quite common for well used DT400 series throttles. If you search the Digitrax "io" group postings I am sure you will find chapter and verse on it. My own older one exhibits the same issues and I find that if I am more deliberate about pressing the buttons it will perform better. By deliberate I mean firm but not violent pressure making sure to hold it just a fraction longer than a stab would be, often helps. Having said all that I don't think there is much you can do. There has been discussion about dismantling the throttle and cleaning the interface between the buttons and the circuit board but from experience, getting into one of these throttles is not as easy as described. Geoff

What an absolutely stunning photo of the Tamar bridges and the Western. Geoff

Is this of any assistance? Taken at Didcot GWR last year. Geoff

All this discussion about baud rates is very bewildering. When I ran into this problem " avrdude: ser_open( ): can't open device "/dev/cu.GeoffreyRobinsons iMac-B-2": Resource busy" and contacted the vendors 'Digitalcure' they offered this advice: " New message from: digitalcure (20,574) Hi Geoffrey, Firstly, thank you for your purchase. Sorry to hear of the issue you're experiencing. As you know, we genuinely test and upload our own sketch on the day of dispatch. This sketch makes the onboard LED double blink (a single flash every one second is the standard sketch) and output 'DigitalCure' to the Serial Monitor. Unfortunately, my knowledge of the MacOS is severely limited. But have you installed the CH340 Serial to USB drivers? If not, some guidance can be found here: https://learn.sparkfun.com/tutorials/how-to-install-ch340-drivers/all#mac-osx If you have installed the CH340 drivers, please could you select the correct port in AIDE and open the Serial Monitor. Please make sure the baud rate is set to 9600. Could you tell me what you see, perhaps even a screenshot? And at this point, could you try to upload your sketch again. Thank you for your cooperation and patience. Well I downloaded the driver, not something I had to do with my initial foray into this project but I couldn't find a way to check the baud rate of my MacBook Pro, nor could I open the Serial Monitor, getting the same error report. I even went so far as trying with a fresh download of the appropriate Arduino software on my Windows 10 machine which I haven't used for this project before but I still got the same result. This is all well out of my comfort zone so I think I will just put up with having to provide separate power to the motor shield and usb power to the Arduino on my original set up. If anyone wants the two new Arduino UNOs to try out just PM me. Geoff

Hello Ray, another Ray (@Tender) posted the list of components to build an Arduino controlled Stepper motor driven turn table on page 1 although the list was quoted again somewhere around page 8 or 9 I believe. I must have started to venture into building mine after following through from page 1. I have enjoyed many years of faultless working until a power supply wire became disconnected. After re-connecting it to the incorrect output from the power source, albeit volt free as far as I can tell, my set up will only work if I power the Arduino from the usb socket and the Adafruit motor shield from the original source. i have purchased two replacement Arduinos but so far have not been able to upload any sketches to either of them, always getting a failure to up load "source busy etc" error report. For the first one I bought that even happened with a fresh download of the Arduino IDE software on a Windows 10 machine which had not been previously used for such a job, I had previously used my ancient MacBook Pro. Depending on your experience in these projects you may be better off starting at page 1. All the best. Geoff

Good afternoon folk. this is by way of an update since the last entries on this thread. I have powered my Arduino Uno from a spare iPad charger connected to the usb socket along with the motor shield being powered from the original power supply from the ESU Switch Pilot with the jumper link removed. The turntable works as reliably as ever so the original inconvenience has been resolved. There remains the nagging issue of why this problem arose. As was suggested I obtained a "clone" Arduino Uno but when I connected this to the usb from my MacBook a whole series of leds lit up (on=steady, L= double flashes and RX= single flashes.) and when I tried to upload a sketch it failed with the following error report; avrdude: ser_open( ): can't open device "/dev/cu.GeoffreyRobinsons iMac-B-2": Resource busy I contacted the supplier who asked me to provide them with screen shots and to check the baud rate, com port etc and down loaded and installed " CH340 Serial to USB drivers" which I have done. Now I am not conversant or comfortable with delving into the brain of my MacBook but I did, via the menus in the Arduino IDE find that the correct Arduino and com port were selected but I could not (dare not) find which baud rate was set. I have not heard from them since, nor have I pursued the matter. When I first ventured into this project I do not recall having to worry about downloading drivers or checking baud rates etc but just connected my genuine Arduino Uno using the supplied usb lead and a single led lit up. I then followed the instruction to upload the "Blink" test sketch which worked and then followed on through the guidance given on here to achieve the working set up. My gut feeling is that there may be something amiss with the "clone" Arduino but the lack of follow up from the suppliers, who admit to having no experience of working with a mac of any sort, suggests to me that I will not get much further with this unit. I would welcome your observations/suggestions. Regards Geoff

Thank you Melmerby, that is helpful information. Geoff

Thank you for your thoughts Simon. I have a redundant iPad charger I could try I guess. If someone could confirm that a replacement Arduino Uno would work with the sketch I have I might be tempted. Regards. Geoff

Melmerby and Simon, flying blind is what I have been doing since the first day of the project to build this turntable mechanism but thanks to the generous help of everyone who contributed to the project back in 2017 I managed to create a reliable, accurate working turntable until the events of a few days ago. How the power supply wire came to be disconnected is a mystery but I could have dislodged it while trying to resolve another unrelated issue. It would seem that my mistake in connecting the dislodged wire to a feedback output on the Switch Pilot rather than the common to which it was originally connected may have caused this problem since I find it difficult to believe the disconnection itself could have caused such a failure. The "normal" power connection is from the "Output A" and "common" of the Switch Pilot to the power jack of the Arduino and then via the jumper link on the Adafruit Motor Shield. This arrangement still works in as much as the LEDs on the Arduino and the Motor Shield light up and the turntable will go through its initial rotations but there is no response from DCC commands. If I power it through the Motor Shield connection with jumper in place the same result is achieved. If I remove the jumper and connect the USB lead to my Mac Book but leave the Mac Book closed, so effectively asleep, and leave the power supply connected to Motor Shield the turntable will operate normally to DCC commands. I have checked the continuity of the ground link between the DCC interface and the Motor Shield and it is good. I have mechanically checked (given them a tug) all the other connections between the DCC interface and the Motor Shield and they appear good. From what you both have said I suspect that something has failed on the Arduino board in the area of the I/O connections which is where I suppose the instructions from the DCC commands are handled to cause the turntable to respond appropriately. I certainly don't feel confident to dismantle the set up to go hunting around the Arduino board for the problem and I imagine it could be a significant challenge to replace any defective component since I guess they are all tiny surface mounted devices installed by machines. I suppose I could consider replacing the Arduino but then the pessimist in me feels that something will have been "updated" which will mean the sketch I have will no longer work. For the time being at least I will just take my Mac Book to the railway and connect it up when I have running sessions. The railway may not have too much longer to live in its present form as we are hoping to move house when sanity returns to the housing market. Thank you both for your help and interest in my problem. If you should have any further thought or suggestions I will be pleased to read of them and consider whether I could implement them. Regards. Geoff

Both the Arduino and the motor shield are supplied with 8.8 volts from an ESU Switchpilot using the jumper plug on the motor shield to share the power. This arrangement has worked, and still does, for the last 5+ years. It would seem that when I reconnected the detached power wire on the Switch Pilot which had caused the original failure to operate, initially into the wrong connection, a feedback circuit rather than the common, something on one of the boards may have been damaged. I have subsequently checked and there does not seem to be any voltage on the feed back connection on the Switch pilot but who knows what may have occurred in the few minutes it was connected like that. Simon suggests that somehow a ground connection has been lost and when I connect the usb socket on the Arduino to my Mac Book that ground connection is made good allowing the turntable to operate correctly in response to DCC commands. In that situation the power supply is connected through the motor shield and the jumper plug to the Arduino. Under normal operation, without the Mac Book connection, the Arduino power socket would be used with the jumper plug powering the motor shield. Looking again at my DCC interface board, the ground wire on the onto isolator is connected to the ground point on the motor shield through the blue wire. Perhaps I need to check the integrity of that connection. Regards. Geoff

Simon, I checked the integrity of the ground connection between the DCC interface board and the motor shield with a continuity meter and it is sound. I also checked the mechanical integrity of all the connections to the motor shield and the DCC interface board and all seem good. As an experiment I fitted the jumper plug and left the usb cable plugged into the Arduino but not connected to the mac book and powered up the turntable. Of course it just went through its set up rotations but didn't respond to any DCC commands. In the absence of the circuit diagram for the DCC interface board, lost in the great hosting company failure, I am stuck unless Ray (tender) see these posts and can repost the circuit diagram. For the time being I will just have to take my mac book up to the railway and connect it up to use the turntable. Regards. Geoff

Above is the list of components used in this project. It can be found way back on about page 13 of the thread. Geoff

The DCC interface board was built using a circuit diagram posted by Ray (Tender) if I remember correctly. There are three wires from the Hall Effect sensor, two from the DCC accessory bus, two to I/O connections on the motor shield, two to 5v and ground on the motor shield and the white wire, which doesn't connect to anywhere and which I believe is available for a reset connection which I have never used. So, four to the motor shield, three to the sensor, two to the DCC bus and the white wire, ten in all. Geoff

Thank you for your reply Simon. As far as I can see there is only one external ground connection and that is between the DCC interface and the Motor Shield. I can check those connections are good but after that I guess it could be some component failure, presumably on the Arduino board. Regards Geoff