Home Forums Conversions Blue Hymek – Traction

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  • #1266
    Edward
    Participant

    Firstly, hello everyone! Really glad to join the Big Big Forum!

    Here’s my question:

    I have a Hymek, which hasn’t been used for the best part of 20 years. I have modified this, to be controlled by an ESP32 with motor driver. The main issue I am facing is traction. Even two coaches/gondolas is too much for it going round a 90 degree bend or over points. It will just get stuck, spinning its (single) driving wheel. I have see many videos, especially from Spyward’s YouTube channel, of the Hymek pulling much larger consists with ease. What should I do to improve traction? Is there anything worth doing to the motor to help it run smoother?

     

    Here’s the back story:

    I remember the Big Big Train set was very occasionally out at my grandparents when I was very young. 20 ish years later, this has been found in the attic unused pretty much since I last saw it, and I am determined to make the most of it! I am keen to make modifications to improve the locomotive, however, the overarching aim, if possible, is to not modify the body work at all.

    The first thing my brother and I have done to the locomotive, is added browser control via Wi-Fi. What we have done, is removed the D cells, and replaced them for a pair of USB battery banks. One is powering an ESP32 WROOM, and the other is powering the motor driver that’s controlled by the ESP32. When the ESP32 boots, it connects to my home Wi-Fi network. Logging into the IP address from any device with a browser, such as smart phone, tablet or PC, presents you with the controls.

    On the left hand side is a reverser fader, which has three steps for forwards, neutral and reverse. The throttle fader is on the right hand side and is a linear fader, fine tuned with a min level and max level driving the motor. The fader can be operated by a mouse scroll wheel if on PC. The percentage of the throttle is displayed on a classic analogue gauge above the two faders. For a realistic speed around a standard layout, roughly 50% is required.

    The control is excellent. However as mentioned in my question above, the issue I have encountered primarily is traction. Any guidance would be very much appreciated, and also any guidance on how to get the most out of the old motor would be much appreciated.

    Many thanks,

    Edward

    #1267
    Richard S
    Participant

    Hi Edward,

    Your remote control sounds very interesting, maybe do an article here on how you did it?

    How heavy is it now it’s got different batteries, maybe it just needs more weight? I converting one earlier this year to metal wheels to run on standard 12v metal track with a motor in each bogie and even with 2 driven axles it sat on the spot spinning it’s wheels until I put the original 4x D cells back in it to give some weight, then it went like the clappers!

    Another possible cause could be the original rubberised traction wheels have gone hard and aren’t gripping any more. I have replaced most of the drive wheels on my Hymeks with new ones made by ybot999 on eBay. After that they do pull a decent length train. Here’s his current eBay listing: https://www.ebay.co.uk/itm/293759671193?hash=item446570db99:g:b80AAOSwEBhdfldl

    Regards,

    Spyward    🙂

    #1268
    Edward
    Participant

    Hi Richard,

    You are exactly right – weight was the main issue. I am using a pair of slim USB battery banks. They are each the length of two D cells, however about half the thickness of a D cell. I’ve therefore added two short lengths of thin pipe full of ball-bearings and covered in tape, that sit on top of one of the USB battery banks above the motor bogie. There’s still just enough space to get the roof on. I have also glued the driving axel, so that now both wheels are driven rather than just the one. Previously the axel would spin along with only one of the wheels.

    Those traction wheels look good. They might have to be the next upgrade.

    This weekend I did a full strip down of the motor too, which now runs much smoother. So the Hymek is now performing very well!

    This is the hardware configuration I am using…

    https://learn.sparkfun.com/tutorials/tb6612fng-hookup-guide

    It is a very neat modification, and you can get really responsive fine control from the web-server.

    The only issue I am now having, is that at prolonged high power, the ESP32 will power cycle itself. I currently have no idea why – for some reason when the motor is driven at speed for a long time the motor driver is making the ESP32 unhappy.  The simplest short term solution is to not run it near full power for a long time! To be honest this isn’t an issue – that speed is far too fast to be realistic for the radius of the curves anyway.

    Thanks very much for your time.

    Edward

    #1269
    Richard S
    Participant

    Hi Edward,

    I hadn’t registered only one of the driving wheels on the axle was working, that will definitely make a difference!

    The wheels on eBay are quite good. They are softer on the outside than in the middle so give quite good grip. He also sells replacement buffers if you have any broken ones.

    Regards,

    Richard

    #1270
    Edward
    Participant

    Hi Richard,

    Yes – I realised the plastic on one of the wheels where the axle passes through had worn, meaning the wheel wasn’t spinning. The glue is a temporary fix, and I think I’ll get those traction wheels as the next update.

    Thanks for the heads up on buffers – one of my buffers has a small chip out of it, so I’ll get that sorted at some point.

    Edward

    #1273
    Edward
    Participant

    Web-Server Controls

    This is an image of the controls you see, when you connect to the IP address of the ESP32 in the Hymek on a smart phone. My brother has recently done a software update, meaning you can now have multiple devices connected simultaneously, allowing multiple people to control the Hymek at once. Or you could have one person controlling, and another person monitoring the power gauge!

    I was reading the other day, there are only four real Hymeks left in the UK. Two of which are on the West Somerset Railway, which is less than a five minute walk from my house!

    Edward

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