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  • Author Author: hifromkatie
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Small circuits - Ideas needed for my Fidget Cube!

hifromkatie

Hi all!
I'm currently working on an element14 presents project, to make a electronics/engineers fidget cube. What do you think, good idea?

My original aim was to make a 1" cube with small circuits on each side, but fairly quickly I realised this was going to be tight on space, I have now upped the size to 50mm cube (approx 2").

 

My design spec is as follows:

  • One side is a power supply, has a LiPo battery input and outputs 5v to 5 Molex PicoBlade connectors.
    • Pin1: +5V
    • Pin2: GND
  • Each side is completely stand-alone, has no dependency on any other side, other than the power connector.
    • All processing must be done on that side's PCB
  • The visible area of each side is 40mmx40mm
  • The PCB is 44mm by 40mm (This has a 2mm edge on 2 sides to slot into a 3D printed framework which will hold all the PCBs in to a cube shape.

 

I currently have the Power supply PCB designed, this also includes a fidget element of a push button which will turn 8 LEDs on and off

Front and Back:

imageimage

 

 

 

The next side I have designed is a logic gates and Binary counter board.
The top half has inputs A and B, and surrounding them the output of the following gates, based on input A and B, OR, XOR, NOR, XNOR, AND & NAND.

The lower half has a 6 bit binary counter, with a button to increase and decrease the counter.

 

Front and Back:

imageimage

 

I am planning on a "sketch side" which will consist of an LCD or OLED display and a joystick which will allow you to draw lines on the screen (Think Etch-a-Sketch).

This is currently proving hard to fit into the space and design requirements, but I think I've got a solution, but I haven't modelled this yet, so you might just have to trust me on this one (and I'm desperately hoping I've done the PCB correctly for it to all work like I've planned!)

 

The framework to hold these into a cube will be 3D printed, and currently looks like this:

The red is the top half and the blue shows the bottom, these will slide over the PCBs due to a groove on the 4 outside faces. The top and the bottom will need some hotmelt glue or other fixing method designed into the 3D print to hold them in place. Potentially an internal framework which will push against the back of the PCB and also securely hold the LiPo battery pack.

image

 

So what do you think of this idea?
Have you got any suggestions for the sides I've already come up with? Improvements, or criticism welcome!

I still need 3 sides, if you have an idea for a side then please let me know and I can design it for the cube. Or if you would like to try designing a side I'd love to see your design.


With the sides being independent and fitting the design criteria, I'm thinking they could be interchangeable and swapped in and out.
We could invent our own swapping system, if someone designed a side and makes a few and swaps them with other people who've made their own, we could all make our own unique fidget cubes!

Please feel free to tell me if I'm getting carried away now...!

  • Consider "Touch Switches"

    Physical switches tend to be a bit large.    There are lots of "touch switch" examples online using cmos IC's (eg. How to Build a Touch Sensor Circuit with a NAND Gate chip ) which only need a couple of exposed PCB trace "probe points" in the HMI (human machine interface) area.  Such switches might implement "momentary contact", latched, debounced, auto repeat,... functions into these small spots on the PCB. Many cmos MSI (eg., 74HC4011,...) chips have been revived in surface mount versions possibly making them small enough to be located very close to a trace to be touched.  A "crossbar" switch design on your PCB could provide a very large number of switches in a very small area.    Latched switches might be mounted with an LED to show which switches are in which state with either on/off or color either at the switch or elsewhere.   Using such "touch switches" can dramatically shrink the input "human/machine interface" (HMI) footprint on your fidget, thus greatly expanding the range of applications you might implement.  Touch switches can be one finger spanning two traces, one hand on one trace and a finger on another, one hand on a trace and another hand holding a stylus to touch points in an HMI input area.  An HMI input area might map to a separate HMI output "screen" far enough away to be seen without the input finger obstruction.   There is a whole world of cleverness these I/O area shrinking tricks can make accessible since they greatly increase the HMI input resolution.

    _______________

    thewildotter

  • I have thoughts,

    Would the sides ever connect to inter-communicate across an edge?

    Would that happen on the underside so the 'internal' of the cube?

    Would the cube ever be enclosed? How would it 'latch onto' or 'attach' or 'plug into' the PCB if so? Maybe a mounting hole in the PCB design for that to happen.

    Could a purposeful 'clear' side of the cube be done where seeing the inside is a fidget in and of itself? Visible orientation reaction inside the cube?

  • in reply to hifromkatie

    In theory, you only have to narrow it down when you finally assemble the cube. e.g. you could design 10 different sides of which you select 6 at any given time to form a unique cube. When you get to 12 sides then you can have 2 cubes but then not only do you have to decide which set of 6 to form into each cube but then which cube to fiddle with first... image

  • in reply to beacon_dave

    Thanks, they are super ideas.
    I like the maze idea, pretty similar to the sketch side, but maybe they could be interchangeable sides, or possibly put together, and have 2 options with the 1 screen for the display.
    I'd been trying to think of sound and what could be done with it. but displaying it as a output in brightness or spectrum analyser type display is perfect, I hadn't thought of doing anything like that.
    The spirit level and countdown timer are great too though, I think I'm gone from not being sure on what to do, to having trouble narrowing down these last 3 sides! So many good ideas image

  • in reply to dougw

    Yes, I want lots of interactivity. I though of sound but couldn't think of how to use it, but maybe mixed with motion to control the pitch etc?
    Hadn't thought of temperature, I'm going to see if I can add that in though. First thought was maybe a pad that as you hold your finger on it warms up and a bar graph/LEDs goes up and down as it cools back to room temperature.
    So many good ideas, I'm going to have a think about those sensor suggestions, it would be super to incorporate light, shock temperature etc
    Thanks