Can arduino mini handle 4 identical display? (hologram)

hey guys!
Im looking into making my girlfriend a nice gift, my plan is sort of cube that will have a hologram heart in the middle of it,
this came into my head a few hours ago after watching radeon holocube, and is a very very wild idea... probably wont come to life sadly :stuck_out_tongue: :smiley:

the idea is as follows :
4 small screens will be laid in a way where each screen is below an inverted glass pyramid side, this will create the sort of "smartphone hologram" thing, like here

now - since the hologram works by displaying 4 identical images, each rotated by 90 degrees with respect to its previous brother, does this mean I can simply connect 4 screens on the same exact wires? ie 1 wire out of the arduino into 4 different screen (signal wire) ... and more importantly - can an arduino mini run it?
please note - i do understand that it has very little power, but the "images" im planning on displaying are literally images such as this that are single coloured, and the displays we are talking about are those...

again - this is a very very very rough idea, so please, join in and help. should i use different displays? what arduino fits the best? is the idea impractical?
also - Id like it to be sort of "plug and play", by that itll be powered by a small powerbank or a battery, and will simply turned on once connected to electricity.

You might do better by using just one large screen rather than 4 small ones. It might sound wrong, but it would actually be smaller by doing so, and probably use less power.

Id love to, however money is of the essence here, all the screens that i saw are 50-100$ and higher, and its very much likely to fail...

few Q's.

  1. will the arduino mini be able to run it?
  2. can I connect all 4 monitors to same signal wire?
  3. how come it would use less power? those monitor are overall much smaller in pixel and dont have colours than a bigger one.

thanks!

In the Arduino world, anything over about 200 pixels wide is considered to be "large". The Arduino UNO doesn't have enough memory to store all those pixels in its memory. Larger screens work by allowing the Arduino to specify drawing primitives like lines and squares and the display has its own processor which has enough memory to remember what colour each pixel is.

Many of those larger displays use bus-type communication such as SPI. That means the displays all share the same data pins except for one "select" pin that is different for each display.

The specific display you linked to uses the I2C bus. (It has SDA and SCL pins labelled.) That allows all devices to share the same data wires and the Arduino must send an address before each command so that the correct device knows it is being called. Without looking into it too deeply, it appears that display can only select one of 2 addresses, so there's no way to share 4 displays on one I2C bus.

Thanks ! Il be honest with you, i had a raspberry pi, and im not quite sure hiw the whole arduino business work, but though id give it a shot.
Isnt there a way to increase the arduino memory? Given that i only need black and white pictures, would it be that much? Also - cant i connect the 4 displays signal wire into 1 wire, and then use it as a signal from the arduino? That way the arduino sends signal to "one" display , yet the signal gets split into 4 different displays, each showing the exact same image, and there by all 4 ona single address, please note i have no idea if its even possible or would work, asking to build my knowledge.

I was more thinking of something like THIS. It would be cheaper than 4 of what you listed. As for size, It would be a little smaller, since the small oled’s would have to be placed corner to corner. Using one screen simplifies the wiring involved.

By using the 4 screens, the base of the cube would be almost 2 inches. Using a 3.5 TFT means the base would be similar to what is used to do this with a cell phone.

The one i placed is 5 for 25$, and also, they are smaller, and u dont need to have a middle space, as the hologram is displayed on 4 corners, ie:
H
H O H
H
Key : O - empty
H - picture slot
Also, using 4 smaller screen would allow the full screen size and pixels to be used to its max potential, where on the big one - youll have many dead zones where the LED is simply wasted... and another thing, if im not mistaken , oled has higher lumen rates...

An illustration on what i meant with the dead space and such, (i dont know if i explained it well enough with my challenged english),
Using 4 different small displays:

O
O-H-o
O

Since H is the same display rotated by 90 deg, all of the display will be useable,

Using one big display:
(Remember its not cube)
H O H H
O H O H
H O H H
Where O - used area
H - wasted

So after all, my question is, can i connect all 4 displays on same address given that all will display the EXACT same photo in the same time?

Yes as long as all the wires are inputs to the display you can connect them together and drive them from the same Arduino outputs. The image will be the same. However I am not sure the result will be very 3D, the 3D effect need different images to work. You will just have the same one.

What happens when you connect two I2C displays that have the same address?

Grumpy mike, googling hologram photos for phone show that the image is simply rotated by 90 degrees, an example :

So why would the screen idea not work given that they are also rotated by 90 deg?

INTP:
What happens when you connect two I2C displays that have the same address?

You are not likely to get image capable display with an I2C interface as it would be so slow. But yes point taken.

However I did say:-

as long as all the wires are inputs to the display

Which would not be the case with an I2C interface.

So why would the screen idea not work given that they are also rotated by 90 deg?

The ones I have seen have had different images. With the same image you can not have any 3D effect.

Grumpy_Mike:
You are not likely to get image capable display with an I2C interface as it would be so slow. But yes point taken.

However I did say:-Which would not be the case with an I2C interface.
The ones I have seen have had different images. With the same image you can not have any 3D effect.

thanks, saved me over a month of waiting probably, can you please attach a video/ image of the hologram images you meant? are there any other cheap (5$) and small (1 inch ~) monitors that can change the IC2 ones?, the whole thing suppost to fit in a small cube,

are there any other cheap (5$) and small (1 inch ~) monitors that can change the IC2 ones?

What I2C ones? The one you linked to in the first post is an SPI interface.

Those oleds come in both I2C and SPI, I have one of each. I don't think the 328 has enough mem to run 4 even if you could config 4 addresses.

But you don't need any more memory for four if they are all going to show the same image.

INTP:
Those oleds come in both I2C and SPI, I have one of each. I don't think the 328 has enough mem to run 4 even if you could config 4 addresses.

as said, they are going to show an identical image...
does it mean I can use 1 address and 1 cable for all the displays?
should I use SPI or I2C?

Grumpy_Mike:
But you don't need any more memory for four if they are all going to show the same image.

will it be an issue though? there are many variants of those displays, some have I2C, some SPI, and some both...
can i run all 4 on a single address and single signal cable?
another question - is there a way to add memory card to the arduino? one that will hold the images as an example, and then simply recall them onto the display.

can i run all 4 on a single address and single signal cable?

Yes for SPI no for I2C.
With I2C if there is an address select line then yes you can use one pair of wires.

With SPI as long as you don't need the MISO line then yes. If not then you need a data select one each MISO line to select the one for each write.

Basically their are ways round things, but we need to know the exact display before we can offer definitive circuits.

Grumpy_Mike:
But you don't need any more memory for four if they are all going to show the same image.

Im just checking an option for different images :), sorry im absolutely CLUELESS with arudinos... can you attach a photo / video of the hologram you talked about? the one that doesnt rotate the screen by 90 degrees?

the one that doesnt rotate the screen by 90 degrees?

What?
I was saying that the ones I have seen use different pictures.

Can you send a video or a photo of it? As i want to make it as best as i can! Thanks!