ArduBigBOY (WAS: My Homemade: Pro Micro, SSD1309, with Flash Cart)

Sorry, my mistake. You are correct. You could probably get away with 2 or 3.

Another consideration is that if you used them for TX and RX, a custom bootloader would be required. Currently the unaltered Leonardo bootloader is used and @bateske didn’t want to make any changes to it.

Having the buttons directly on the pins means they can be used to trigger interrupts. Although I’m not aware of anyone doing this, using a shift register eliminates this possibility.

Yep, good point. But, does anyone actually care if the bootloader toggles Rx/Tx LEDs? I’ve never needed to monitor those myself.

Still, in our theoretical re-design, a single WS2812B could replace the existing RGB. This only requires a single basic output pin and frees up at least 2 PWM enabled outputs for other purposes.

True. Although I agree that there may not be anyone actually doing this. I suppose it come in handy to wake the device from a deep sleep mode. But Arduboys have an actual hard on/off power switch, so I’m not sure that a soft power on/off would be needed or useful. It might actually confuse people if the device looked like it was off but was just deep sleeping. They would try to turn it back on which would actually turn it off.

Again… all of this is theoretical. I am not actually proposing making any of these changes at this time.

After procrastinating on this for way too long, I finally finished up the v1.0 PCB and sent it out for fabrication (10 pcs ordered).

Now I just have to wait for ~2 weeks for delivery. (I already have enough parts to build 10 of these)

Compared to the earlier draft, this has a lot more pins broken out to the expansion headers (just about everything possible). I also labeled all the expansion pins, added the buzzer, added battery pads, and added some mounting holes.


Nice work … the 2.42" OLED is a nice unit.

I finally received the PCBs today (should have gone with DHL instead of cheaping out).

Anyway, I built one up and tested it out this afternoon. Everything seems to be working great!

The internal flash is using a different chip select pin (E,2) than @Mr.Blinky’s default one (B,2), so I created a pull request for his Cathy3K bootloader repo to add support.

As a reminder the ArduBigBOY has these features (different than the official Arduboy):

  • 2.42" SSD1309 OLED display (need to use @Mr.Blinky’s patcher script or compile with his homemade boards package)
  • Built-in 16 MB SPI flash cart (with bootloader support thanks to @Mr.Blinky’s Cathy3K bootloader)
  • 700 mAh lithium ion cell with protection (TP4056 based charge circuitry)
  • Hardware mute switch
  • Same pinout as the official Arduboy to easy with uploading existing .hex files (after 1309 patch)
  • Expansion header with almost every pin/signal broken out (allows for external SPI, I2C, UART, etc…)

I have enough PCBs and parts for 10 more of these, so if anyone would like one of these built up, send me a private message. The parts cost comes to over $25, and it takes a good hour or so to solder one of these up, so I think $45 + shipping is probably reasonable. I’m also willing to trade one of these for an original Arduboy if someone has an extra one to spare.

I will also be working on a 3D printable case and some expansion modules soon. I already have a double sided ‘cart’ ready to go, but with no software support for it yet, and with a 16 MB internal flash already installed and working, I’m not sure how useful it will be.


Very nice! I like it! Look at all that board space… blackberry keyboard :slight_smile:

You never go with DHL if you can cheap out. Are you going to publish the pcb?

Looking good! Love the pth crystal to smd bodge (I’ve even done the opposite, a smd crystal on a pth pad, on occasion).

Thanks! Yeah, if felt wrong sending out a PCB with so much free space. My usual designs are much more compact and cramped because I am always trying to optimize for as little area as possible (to reduce costs… using OSH Park). This time, I actually needed to have the larger footprint (and went with PCBWay where any size under 100x100 is the same cost).

Yeah, that’s my usual approach, but this time I wanted them so badly that the wait seemed painfully long. I am planning on publishing the pcb (and schematic), hopefully this Friday.

Yeah, still waiting on the 5032 2-pin SMD crystals. Supposedly they have been in the country for two weeks already… why haven’t they been delivered yet? :frowning:

Here is a sneak peek of the 3D printed case I have been working on for this (compared to an actual Arduboy):

There are still a few small tweaks I want to make before calling this good enough for version 1.

I am also looking into other options for the buttons because what I have used so far are very ‘clicky’ and I would love to get closer to the feel of the official Arduboy (gotta loves those buttons!).

I did finally get the correct 16 MHz SMD crystals, so the bodge job is gone.

I hope to button up and release everything later this week, in case anyone wanted to build their own.

I do still have a few of the initial small batch run of these available for sale. PM me if interested.


Looking very nice! I like the RGB LED shining through the case. Those vast white surfaces look like they may want some arcade artwork on them.

If you want the correct button feel you are looking for something under 100 nm activation force, or as close as you can get. In smd packages that are easy to source typically 150 is about as low as you will find. Which is OKAY, but still puts you on the threshold of feeling “I wish this was just a little softer to press”. Standard run of the mill button force is going to be at 250.

Arduboy specifies 85nm but I’ve told the factory that anything under 100nm is fine. I’ve tested all the way down to 60 which starts to get too soft. If you somehow have the ability to add a silicon or rubber layer over the button this will improve the button feel as well, I considered doing this in production but figured it wasn’t necessary, and the process might have been complicated or expensive.


Would love to know if you ever sourced those metal ‘domes’ that you are using on the Arduboy outside of going to a ‘factory’. I can’t seem to find them on the usual channels. I probably just don’t know what to search for. With those domes, I can probably fabricate the rest the required button and I already have PCB traces for a soft touch type button.

I did find some decent looking SMD soft touch / silent silicone buttons, but they are much taller (5mm) than would be ideal for this case design (and I have to wait for weeks for slow China shipping).

In the meanwhile, I will look around and see if I can hack apart any keyboards, remote controls, or the like to re-use any of their silicone domes.

You can’t really find them to purchase straight away. The only time I was able to get something like this was to request a sample set from a manufacturer online and they sent me several thousand and almost as many marketing emails.

Check out stuff like this, adafruit is expensive but it’s the right part:

The manufacturer ALPS has some really excellent stuff.

Yeah, I bought some of those, but they are too big for this case (and the pcb would need to be re-worked).

I actually found that I can disassemble the 6x6x2.5 smd buttons that I am currently using (pretty easy to do), and there is a metal dome in there that looks about right. Testing it now.


Yeah all these type of buttons actually have snap domes in them somewhere. The problem is the “land” or the area they are intended to come into contact with. Unless they are designed for a PCB land then it’s gonna be very difficult to re purpose them.

That said, these button matrixes only cost fractions of a penny. You might need to buy several hundred or maybe a thousand but you might not actually be out that much money. I mean, if you’re really committed to the snap dome route. There are lots of options if you go with microswitches too.

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snap dome - That’s the name I was looking for! I see lots of them now. Thanks!

Yeah, looking into that now. I did set up a set of alternating pcb traces that works great with the silicone rubber button domes, but is a bit fiddly with these metal snap domes. I think part of the problem is the pcb tinning is slightly lower than the solder mask. If I raise it slightly it seems to work pretty good, but if I get to much solder on the traces it stops working again. A properly designed pcb trace would make these much easier to use (i’ll address that if I do a v2 board).

Yeah, I have micro switches now, but they are too noisy. Hence the need to look for something quieter.

Snaptron has a range of snap metal domes and offer a free sample box with many different domes to test out. I got one ages ago to test for a potential product and still have it somewhere.

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Thanks! I submitted a sample request. We’ll see if they honor it.

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