3 Speeds Electric Rotating Display Stand Mirror 360 Degree Turntable Jewelry Holder Battery for Photography Video Shooting Props (WHL #62)
We haven’t had a stock product presentation for a while, so why not start 2021 with something new from China… [bitter 2020 stares from the crowd]
Well, for the PCB Tree I figured a 360° view would be nice. I know it does have some ugly holes, but every naturally grown tree has these. Why not get something that not only offers a spinning platter for stop-motion tricks, but instead rotates something on display on its own?
Bought on AliExpress on 12th of December, 8.73€ including shipping, delivered on January 8th – that was a quick one!
It’s a pretty simple turntable with some tiny motor in it and can be powered by USB (actually pretty decent cable included), a single 18650 lithium cell, or three AAA batteries – I wouldn’t recommend the latter, as even with USB and the lithium cell, it does have its limitations. Not sure if it is the controller/circuit or the motor, but it’s not exactly powerful. Frustratingly, it did not work properly with the tree that is just above 3kg, which is about the rated spec (go figure) – the attached LAN cable would interfere although moved separately. I could have sourced power from a powerbank below, circumventing the PoE adapter – but that would have caused even more weight on the bearings, which also did not work to my satisfaction. Furthermore, full load isn’t even possible with all speed settings. Well, should have bought the heavy duty version instead…
The turntable shipped with USB cable and a top cover that is somewhat white on one side and cheaply mirror-y metallic on the other. As you can see, that coating is garbage and one would require a separate real mirror if needed for the display effect. The white surface feels a little rubbery, gathers dust and has no defined color. I just grabbed my China ref panels, it’s certainly off-white.
[Correction from a week later when I threw it away: Turns out that white side is just wax paper covering the self-adhesive back side of the silver dish. Well, when the throwaway wax paper is better than the product, the bin is probably the right place for both.]
The bottom has two battery slots which are aligned in a strange way due to space reasons. I have to say the covers are darn stiff and it hurts getting these off with your fingers – better use a screw driver instead. Also, make sure they are pressed down firmly as they need to latch (which they often do not), otherwise all batteries will fall out. The 18650 holder is longer than expected, so protected cells will fit nicely. Since there’s no fuse and unknown circuitry (see below), plus the cover is a PITA, I would actually suggest using protected cells for that application.
The holes are not covered by e.g. rubber bits, so the entire turntable moves around easily. These are also not screw holes, they’re standoffs for the internal bearings. Not exactly nice, but you’ll get what you pay for.
The top can be removed by pulling hard – it’s just a press fit onto the motor shaft. Careful as this is messy. I actually kept the GIMP auto levels here as the grease has a very intense yellow-green color, almost resembling the radium gin from bigclive. Once again I was disappointed when that stuff didn’t light up under UV light…
Here’s the juicy bits inside – a friggen motor, a tiny PCB and a mess of wires that connects these things to the two battery holders. There’s five plus one off-center ball bearings that the lid rests on, so very simple construction indeed.
Close-up of the PCB (“XRF-138”) bottom. The top is purely used for connecting wires. Motor cable is removable, battery wiring is soldered. The duo LED is just soldered on and bent around the contacts below, there’s a millimeter of space between the pins. A drop of hot snot would be a nice thing if that construction is required for monetary reasons. The LED turns on when used with USB (which could be annoying) and is also a charging indicators. Interestingly, it is a red and blue combo which I think is a first for me.
The circuit board features a ULN2003A that is close to the motor connector. Since it is a 7x NPN Darlington array, driving a stepper motor is a classic use case for these.
The other main chip is totally blank – not erased, but never labelled. So that would be a little microcontroller that does drive the ULN, does some LED magic, and is controlled via the three buttons in front. These change direction of the rotation, rotation angle (or full, continuos rotation, contrary to reports of these on AE), as well as speed. No beeps or lights flashing, one just presses buttons and checks the result.
The lithium cell circuit is separate and has a little DC-DC converter. Not actually sure if that is a step-up for generating higher voltage from the cell, or a step-down to charge the battery a bit more efficiently – it does lack an electrolytic, though. Charging current is 45mA which could also be achieved from dropping voltage the ugly way. Open circuit voltage is 4.14V which is excellent. The AAA holder also has a strange open circuit voltage of 1.4V present – I wouldn’t expect rechargeable batteries to be charged in there (used in series!), but I also would not trust non-rechargeables to be in there…
The little 6 pin chip that does work this magic has marking 17X and the (presumably) MOSFET besides is labelled E50P. Again, the main controller is unfortunately unlabelled.
And here’s what one can do with that, when combined with my new (first proper) tripod:
Yeah, video focus is a bitch…