The last six months have been busy with the J70 Project. Up until April I was pretty well sorting the loco electronics and developing the Android app to control the whole thing. I will not bore my readers with the development of the programming code for both the J70 electronics and the Android app (unless you really want me to!) but suffice to say the loco electronics were written in Arduino IDE and the app was with the MIT App Inventor online IDE using visual block coding as I have no idea how to do this via an actual Android coding language!
The Arduino code was developed initially using STEM teaching robot code that I found online and enhanced for using in the loco's electronics. The electronics consisted of a NodeMCU ESP8266 microcontroller which creates its own wifi network that a smartphone can connect to and control via an Android app. I also included a MP3player for making the various sounds (steam whistle, bell, and various speed sounds). I had to include a DIP switch to isolate the MP3 from the NodeMCU when I programmed either of them. I utilised the blower fan hole from the original design my placing a 57mm speaker in it and 3D printing a baffle box to go over it. I included a Seuthe smoke generator which was controlled via a relay as I had to power it from a separate power source. I used 9V rechargeable LiPo batteries for both the smoke generator and the rest of the electronics and motors.
After much troubleshooting between the Arduino code and the Android code I successfully took the loco for a test drive on the Club G layout sometime before Easter. Once I was happy with this I went about and 3D printed rollingstock consisting of a flat wagon, an open wagon and a brake van. I placed a crew in the loco and a guard in the van. These were pewter castings I had ordered from England but painted myself.
Over a couple of club meeting days I further tested the whole train, finding little things to fix or add to enhance the working. I made my own drawhooks from 2mm brass rod, these had a spring each which I had sourced from our local RC model shop. I 3D printed a spring retainer and retainer box for each of them on each of the rollingstock. The models were very light so I followed some club members' suggestion of adding weight to them. This I sourced as post washes which fitted perfectly between the frames.
Some of the wagons don't run through one of the points on the club layout very well, so not sure if my wheels, the point's frog or check rails, or a combination of both. A fellow G scaler has offered some spare metal wheels to try and I will do this when I next see him at the club.
I'm getting very interested in the G modelling so far. This weekend I took out membership to the UK based 16mm Association to gain a better understanding of the scales etc that I could use on the 45mm Club track as well as take up the narrow gauge aspect as I have always been interested in the quirkiness of the narrow gauge railways of both the UK and elsewhere in the world.
Some pictures below for your enjoyment.
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| Android app screen that I designed |
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| Front view of loco. I can remove Toby's face as it is only held on with BluTack. I put it on to amuse the little kids that come to the Open Days. |
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| Side view of J70. I found a bell from a USA loco suitable to print for this loco as the original design didn't have one. I must mention before it is commented on that the chimney is not prototypical as it should be along the centre line of the roof, not the side, but I was working with what I had printed. I had to design and print a reducing collar for the chimney as the base print hole was larger for a static chimney. |
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| The beauty of this model is that it is basically a box on wheels which allowed for plenty of room in the inside of the model. This photo shows the various components I was able to place inside the cabin. Fun fact: the green wire on the right is connected to the main power supply (not the smoke generator supply) and allows the NodeMCU to measure the voltage and transmit it to the Android app to visually show the voltage and condition of the power supply/battery. |
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| Flat bed wagon |
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| The underneath of the flat bed (also applies to the two other wagons). Axles are 3mm brass rod cut to length. The drawhook provides coupling and the spring supplies semi-rigidness for the couplings. Originally loose fitting, I found connecting the drawhook with a brass link between wagons troublesome as it was always twisting. So I designed and printed a retainer box for the drawhook assembly. Not shown is a designed and printed spring retainer at the end of the brass rod that is kept in place by the retainer. The post washer provides a suitable weight for the very light wagons. |
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| Open wagon |
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| Brake van. I designed and printed a brake stand for both the van guard and the loco driver to use. The stand handle was 1mm brass rod bent and cut to shape. |
J70 idling away and making smoke
I have to link off to my YouTube Channel for the next video as it is too large for Blogger. The video is of the full train running at RMCQ's May Buy & Sell Day.
So what's next? I'll continue to tinker with the J70 and run it at the club, but will now look at other G scale based trains. These may or may not be 3D printed in entirety but 3D could be used to enhance other materials.
I am will still continue with my OO home layout as that is not yet finished.
HO and HOn3.5 will also be on the roster.
3D design and printing of railways based models is now an integral part of my enjoyment of the hobby.
