Slot Car Controllers, Spares and Accessories
PWM Controller notes and upgrades

PWM Controller notes and upgrades

2008: The most recent version is now ready, though still all hand made.
Additional sensitivity adjustments have been included to compensate for the large variation in track power supply voltages encountered on the Slot-it challenge in the UK.
New controllers will have this as standard and it is available as an upgrade to fit to the earlier versions. Price is £20

Upgrade and sensitivity Board features (Trigger 0.0)

10-Stage curve control:
This sets the trigger feel by adjusting the shape of the throttle response curve from linear at setting '0' to logarithmic at setting '9'

10-Stage top sensitivity control:
This changes the upper element sensitivity by adjusting the amount by which the speed jumps from the last wiper segment to the final top contact for full speed.

Fast acting short circuit protection:
This helps prevent the drive Mosfets being damaged by short circuits caused by screws in the track, shoring motor braids, failed motors, or any track condition which might result in high current draw through the controller.

2009 March: Production of the Printed Circuit Boards in under way, and those how are awaiting their orders should receive them by the end of October. It is aimed to have stock available from the web site towards the middle of November.

2009 Oct: still on schedule for stock availability for November. Additional current orders are still being process, so stock will be produced one they are fulfilled.
(The new version is the same as the previous ones, but the boards have been mass produced at a factory instead of hand made)

2009 Nov: The new branded controller handles are almost ready now and the final designs for the electronics are being tested. The new range should be available early next year. Pre-orders are being taken now to send out as soon as the stocks are available.

2012: The new PWM II design has proved well worthwhile having the two selectable MODES working very well together. So far all the feedback has been positive with racers reporting better lap times and even more consistent control.

2012 July: Due to demand for controllers suitable for both positive and negative wired tracks, a dual polarity version is in design now. Details will follow as soon as prototypes have been tested. These additions are proposed for the PWM II and the MT I.

2012 August: The dual polarity version has been put on hold since in this power bracket is becomes an expensive option. It will be considered now for the MT II controller.

2013 December: The PWM II is now supplied with the MODE switches operated from the face plate. It was found that there were times when quicker access to them was needed. Recently also there is a new range of very high current Mosfets available, so future models will use these. If any earlier models come in for repair then these new ones can be fitted.

2014 April: The trigger Curve control is under experimentation to  give a curve shape that will move up as well as down from the linear straight shape. This will give the middle range power band adjustment that many 1/24th races have been asking for. If successful the new graphs and feature sets will be shown on the web site as an optional upgrade.

2016: The automatic power cut feature in the short circuit protection has been muted from now on and earlier versions that come in are being modified during the repair process. The cut-out works well, but causes too much trouble during racing with metal chasses cars that regularly short on the track braids. With the new powerful Mosfets being used the short circuits are handles OK as long as they are brief.

2016: The curve control idea was successful and has been extended now to the rotary potentiometer option for the PWM II. This replaces the rotary switches and can be easily adjusted while you drive.

2017: This year the PWM II has been unchanged expect for the custom addition of back emf reduction circuits for a few clubs with particularly sensitive power supplies. the back emf has the effect of making these few power supplies think there is a fault, and so shut down.

2017 April: From April the PWM II controller is out of stock as many people will have noted. The reason another run of them has been organised is that the current design using discrete components is very time consuming and not really profitable to make. 
I made the last batch of 100 promising myself that I'd re-visit the design to make it faster to produce without compromising the performance or features. 
In that re-think, ideas for the new model developed and I've been working on a new design for a while now. 
This is only at the first prototype stage to just verify the theories on a working unit with cars actually on a track. 
So far it's promising, but like any new design has tweaks needed. In the meantime however, the demand for the PWM II remains, with regular enquiries coming through. To keep things going the plan is to make a new version with quicker production methods so that the PWM II will become the PWM III with little changes and possibly a new casing. I am working on this at the moment, so hopefully soon I should have some news about it all. The web site will show availability once they're ready for sale, and another note about it posted here.

Thanks to everyone for their feedback, support and interest in the products.

2020: The replacement for the PWM II controller is the new APEX.
Prototypes have been made up and tested by several top racers and the results filtered to make little changes to the designs. It is now hoped that the new Apex will be available by about June 2020.




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