Arduboy Sculpture [RIP]


(Kevin) #1

Enough people I know are doing this so I should probably give it a shot.

My plan is to make an Arduboy without the circuit board.

I don’t have my workbench set up at the moment, so that is the first challenge is making a place to work.


(Kevin) #2

What is the smallest gauge wire I can use in this circuit? The screen power supply consumes the most current at about 15mAh @ 4v

The googles revealed:

And it looks like 30 AWG is probably right on the border with 28 having a nice safety margin.


(serisman) #3

mAh is a measurement of capacity, not current. Did you mean 15 mA? If so, that is a tiny current draw and 30 AWG should be more than sufficient (at least at smallish distances).

According to my usual source (https://www.powerstream.com/Wire_Size.htm), 30 AWG is good for about 0.86 A (860 mA) in air (not in a bundle) conservatively. But, I always like to use something thicker (i.e. 22-26 AWG for something like this) for ‘power’ connections (i.e. VCC/GND).


(Kevin) #4

Ohh I was looking at power transmission. So maybe I could go down to maybe around 36. The goal is to make the wires nearly invisible.


(serisman) #5

Most likely. There is a calculator further down the page. Accordingly, a 30 AWG copper wire with a 6 in (0.5 ft) round trip and a 15 mA (0.015 A) current will only have a 2 mV drop (0.002 V), which is minimal.


(Kevin) #6

I’m only going to be going about an inch, could I use 44 AWG? :smiley:


(serisman) #7

Well, that chart doesn’t go that low, but for these low current draws, probably. Apparently 40 AWG is still good for 90 mA or so.

44 AWG should be about 2.5 times the resistance of 40 AWG, or about 2650 ohms per 1000 ft. So a round trip of 0.5 ft is still only 1.33 ohms. At a current of 0.015 A you will still only see a voltage drop of about 20 mV.

Again, 15 mA is a pretty small current. Things get much worse as the current goes up.

Keep these formulas in mind:
V = I * R (voltage = current times resistance)
P = I2 * R (power = current squared times resistance)

You want to make sure your voltage drop and power loss is low.


(Kevin) #8

Not really concerned about voltage drop to be honest, I guess as long as the wire doesn’t heat up enough to burn up like a fuse then it’s gonna work for me :smiley:

Testing stage is next I suppose.


(serisman) #9

Yes, definitely test it out.

Here is another link that talks about fusing current: https://www.powerstream.com/wire-fusing-currents.htm

30 AWG (copper) fuses around 10.2 A or 40 AWG (copper) fuses around 1.77 A.

Aluminum is worse, but still nowhere near the low currents the Arduboy circuits normally see.


(serisman) #10

Are you planning on keeping this in open air, or enclosing it with epoxy (or something). If open air, you will probably need to worry about the physical strength of the wire too.


(Kevin) #11

When I made the original prototype it was running a 328p on an internal oscillator to really cut down on the part count. Not sure what I’ll do here. I guess making it fully compatible would be nice.


(serisman) #12

It would be a lot of fine detail soldering, but using a bare TQFP or QFN ATmega32U4 IC with deadbug style wires and components would look amazing.


(Kevin) #13

Bruh u dont even kno


(Scott R) #14

I was thinking about having a crack at one of these after recently seeing some free form stuff on Twitter. I think it’s common to use brass rods instead of copper


(Kevin) #15

I’m gonna do something more different from that, I have a secret plan! :slight_smile:

Behind the Scenes BlueRay Extra: Mohit and I shared and office together in Shenzhen he is awesome, I’m happy to call him my friend.


(Kevin) #16

Got this in the mail. I dunno if I’ll be able to meet the deadline if I have any issues with the process it will be tight.

The batteries and epoxy should be in by this weekend.

Now I need to change the button input code to be capacitive touch and find a game to test with. Any voulenteers want to get their game working with 1 wire capacitive touch buttons or maybe a little demo-scene for demonstration purposes? :smiley:


(Simon) #17

Would be great to have a memory game like Simon or mole whacking game

Maybe you can hack this game >


(Kevin) #18

It might end up on hackaday I’d love to use something visually impressive but I can’t code my way out of an infinite for loop.


#19

I’m happy to modify existing a game/demo or even to work on a new demo.


(Shawn) #20

Color me intrigued! Cant wait to see the end result.