DC controller question

[KiloWhiskey]

With the appropriate dc wallwart, and a DPDT for the output reverse (which I already have)....will this unit or similar work for a small DC switching shelf layout?

DC 6-60V 12V 24V 36V 48V 30A PWM DC Motor Speed Controller, Durable Stepless Speed Regulation Start Stop Switch for Motor https://www.amazon.com/dp/B07G59S3V5/ref=cm_sw_r_cp_apa_i_j5YsDbKZ94PJM

[Alan]

Sure, why not. The Amazon product combined with a wall wart is essentially what we would otherwise call a train power pack. The momentary action of the start/stop switch might be a bit clunky in actual use. In your application it is equivalent to an on/off switch for the train, not the power.

At the very least it really needs a bigger knob. 

[KiloWhiskey]

I agree about the knob.... I got to reading up on these devices, as I wasn't real familiar with the modulation protocol, which led to arduino .... interesting reading /videos.

[Alan]

The Amazon product is a pulse width modulation (PWM) device. PWM is how DC motor speed is controlled digitally hence the Arduino reference. Any digital device that controls the speed of a DC motor relies on PWM. It is also the secret sauce inside switch mode power supplies (which just about every power supply is nowadays). In addition to facilitating digital control, PWM avoids the heat, power losses, and bulky equipment of conventional transformer/rectifier/regulator devices of yesteryear. PWM is why your cell phone charger is the size of an ice cube and not a shoe box!

[KiloWhiskey]

So .... my ebay loco arrived a bit ago, an Athern SW-7  in SP colors, #2286. This has a DCC decoder unit, a digitrax DN 140 . Has 3 LEDs , headlight front rear and a roof strobe.the violet wire is unused. Now I need a DCC system to test/run this instead of the dc plan. Has anyone used the arduino uno and motor shield /JMRI set up? The loco came from a fallen flag it appears.... on ebay with all his other equipment it looks like... may he rest in peace.