Episode 397: Steam Powered Retropie Console

Hey Dubbie,

I'm glad you enjoyed it. Despite the failure, I had fun too. Even unloaded and off camera, I was completely unable to get the engine to run on its own, so it's hard to say how forceful it would have been, I had some leeway to adjust the gearing, so that was the plan for torque issues should they arise.

The CD idea sounds fun. I'll definitely be playing around, ehem, researching different flywheels and such for the inevitable version 2.

Thanks,

DJ

Hey Paul,

Thank you for the input. You're right about the rectification and I definitely could have sourced more current from my one motor.

As for the engine, I'm still confident it would have worked had the engine worked at all. Off camera after the initial test I tried quite a few times to get the engine running unloaded, but to no avail. Even with proper lubrication and varying levels of water, I couldn't start self running action, but I suppose that's what I get for using the cheapest engine kit I could buy!

I appreciate the offer and may reach out when I reinvestigate this build.

Thanks,

DJ

Please find attached a schematic, for better connection of the bipolar stepper motor, to make more efficient use of it, pardon the schematic, I'm still new to Kicad, and still learning how to use the program but the schematic should give you an idea of how to utilise the stepper motor better, as connecting one winding was probably not helping, I used a voltage regulator as a stand in for the buck converter

I really enjoyed this build, mostly because I think I jut like shiny things, especially if they go round and round. It did seem dubious that such a small steam engine would be able to rotate the step motor but I was prepared to suspend my disbelief. I didn't understand what the weighted crank was for, I would have thought that a balanced crank would be better.

I once made a similar concept energy recovery system using CD-ROMs. The CD-ROM would be spun up to speed (very fast!) by a direct drive DC motor, then the power to the motor was removed and the energy stored in the spinning CD could be recovered by using the DC motor as a generator feeding into a boost convertor. CD-ROMs do not weigh much so cannot store much energy and a normal DC motor is not very efficient at being a generator, but it did actually work and I think a few hundred milliseconds of extra voltage output were obtained. It might even have been seconds.

There were some problems. Sometimes the CD-ROM would come free from the DC motor shaft and fly across the room. Completely unsafe. We fixed this by putting a plastic cover over it. We then had some CDs shatter as we increased the hub tightness and span it at faster speeds. Ahh, those were the days.

Dubbie

Hi DJ,

Love the project you have done here but I like to point out one glaring mistake you made with using the stepper motor, you had a bipolar stepper motor, so essentially a 2 phase motor.  But you used a single phase into a regulator circuit.  If you used a 3 phase style rectifier circuit, you would have generated additional current and made the circuit more efficient. https://www.electronics-tutorials.ws/power/three-phase-rectification.html  This is a link to an explanation of a 3 phase rectification circuit, of course with a bipolar motor you just drop a phase off, so you have more AC pulses in the output providing more current for the same rotational motion.  And a more efficient use of the motor, it would not take much to alter to use both phases of the motor and provide more input current to the regulator.  But as part of your testing you should also check your output current whilst the motor is running, not just the voltage.  So if you alter the circuit to utilise both phases for energy you will find it will generate the power needed to be rectified.

On the steam side of things, it is possible to machine a small steam engine if you have access to a metal lathe and the patience to build one, I have built one in the past, you need patience and an eye for detail.  But to add the steam engine you selected was far too small for the torque output required to drive the stepper motor, you need at least one that is 70% bigger to have sufficient torque output to drive the stepper especially once you start to draw at least 1 amp of current from the coils.

On another note, you could 3D print a similar style steam engine and power it with compressed air, to demonstrate the principle of using such a concept to get it working in the absence of using a steam engine. I would recommend using Polymaker Polysmooth for the main piston chamber or similar off the style container for the main piston chamber.  As pressurised air is just as easy to obtain if you have a bike pump handy to pump air into an air tank as your fuel. And an air reservoir pressurised to approximately 100PSI (depending on size) would give you approximately 5 to 10 minutes of run time, as long as the pressure output is regulated to deliver this pressure evenly, to maintain run time.

If you like I could email you some more detailed information to get this side of things working.

Regards

Paul

Thanks Bart! Yeah, this may have been the cheapest steam engine kit I could buy...

Nice video.

You did a great job of showing the difference between making and engineering a product.

An Engineer would have done some calculations to see how much power the steam piston would need to properly drive the generator and sized the steam component appropriately.

Other than those details, I enjoyed the build and the basic idea of a steam punk implementation.

DAB

The console is really well done, but I don't think that silly desk toy was going to cut it even if it wasn't a terrible design. This is a an old toy steam engine I inherited from my grandfather (it's almost a century old. It works, but I'm not giving it away). Something like that could probably run it; I think it was part of a line of model factory machines that it could actually run, so a small generator shouldn't be a problem. (if you'd go that route though you should try to make a period-accurate design, DC generator for it)