Used in 'Touch Screen'mode in 'The Brutalist' loco, soon to be seen in 'RC' mode in a new project.
Comprises DISCO-F746NG computer, mounted on custom interface board.
The ST DISCO-F746NG module is one of numerous demonstration computer modules with 'mbed' programming support. It is bristling with goodies and features, most of which are not used for this project. The interface back panel is simple enough, see schematic.
Onboard non-volatile memory is used to store setup and use data. This includes selected operating mode, one of 3 currently offered :-
The 'Brushless Brutalist' Loco uses Touch Screen Slider drive
Radio control modes were developed in collaboration with the 18100 Turbine Loco project (more of which anon).
The unit also contains a data logger (ask ffi), and odometer recording total distance travelled - metres.
The screen shows three mid-20th century UK military inspired 'moving coil' meters, the largest, central one is the speedometer (currently calibrated for up to 12 MPH - other speeds available by simple code tweak), the other two show system voltage and loco / vehicle power consumption.
A Radio Control receiver may be connected to the TS2018 interface board. The receiver is powered by the TS2018. Up to 3 channels are supported.
In either RC mode, one channel may be used (e.g.) for horns, where moving a Tx stick to one end sounds a Hi horn, stick to opposite end sounds a Lo horn.
In RC mode 1, a second channel (preferably with spring loaded centre-zero Tx stick) applies full regenerative braking at the centre setting. Moving the stick a short distance reduces braking effect, until braking gives way to application of drive power. Direction of travel is selected by moving the stick back or forward. This works well, but a lot of action is crammed into the available stick movement !
In RC mode 2, a third channel is used to set direction. Typically a 3 position switch on the Tx will be used - Forward -> 'Forward', Back -> 'Reverse', Centre -> power off, braking on. In this mode, the driving stick sets the loco to 'drift' (no power and no brake) in the centre position. Moving stick forward applies drive power proportional to stick deflection. Stick back applies regen braking effort proportional to stick deflection.
The TS2018 may connect to a laptop or pc USB. Use a dumb terminal programme, e.g. 'PuTTY' (or Mbed Studio for the full works), to setup serial comms (115200 8N1). With comms established, issuing the command :
prompts the TS to list all instructions it currently respond to.
Code compiled using Mbed OS 6.16. Code at Sept 2022 - Complete Source for use with Mbed Studio here, latest binary here
The display sometimes shows a flickering instability. This tends to last a minute or two before regaining stability. Having used the F746NG module for several projects over 7 years, much time has been wasted trying to nail this down - without success. It is an intermittent display problem, having no effect on safe and correct operation of the processor and code. Not a 'serious' problem, but enough to discourage me from offering these for general sale. Feel free to build your own, contact me ffi.