Core Electronics Forum

A new base board for the Adafruit Itsy Bitsy M4

I’ve been tinkering with an idea for a general-purpose base/carrier board for the Adafruit Itsy Bitsy M4.

The idea is to have an Arduino-like system that allows stacked boards to be addressed and also allows for small amounts of IO circuitry to be connected to the edges of the main PCB.

Maybe this video will help explain.

Video about the board.

I don’t show the “walls” in the vid because they are not designed yet for this version, but here is a photo of a previous version that is very similar.

I just sent V2 of the new design off to PCBway, I will load a couple of them and see how they work, based on that I’ll decide if I want to continue with the project.

Anyway I thought you guys might find it a little bit different to other offerings currently available. It will be open source but apart from a networked monitoring system for my solar system it’s just a bit of fun for me that helps me keep my design hand in.

Rob

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Hi Rob,

Thanks for sharing this it looks like a well thought out piece of design work, I wasn’t familiar with the Quub concept so thanks for the summary at the end.
Oh, and the Grey Nomad Designs logo is a very nice touch!

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Hey Rob,

I had a look through your site and came across your boards with the angled connectors, they look fantastic!! Cant wait to see it in action :smiley:

Liam.

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@Trent It’s something I’ve been toying with for a few years, since I finally got sick of the Arduino limitations, not that anybody else cares about them :grinning: It’s had many incarnations but I might finally get this one up and running.

Normally I do the CPU design as well, but I’m a bit over that and bootstrapping a new CPU design from scratch can be a pain, so I decided to go with the Itsy Bitsy.

The logo is also my caricature :smiley:

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@Liam That design was a system of DIN-rail-mounted monitor and control boards I designed for a Brazilian company. Every board had it’s own CPU and they communicated via an I2C backplane.

The blue modules at the top.

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Hey Rob,

That looks great! The cable management is impressively clean, something we’re unfortunately not too familiar with for photos that are generally posted on the forum :sweat_smile:

I’m curious what the control board was used for, obviously it was for some industrial application similarly to how PLC were often mostly used back in the day (I’m assuming it’d be running at around the 12V or 24V mark?). Also if you’d like to shoot through the photo of your V2 once it comes back from PCBway (shipping from China has been taking quite a while to get here to Australia recently as we’ve found with some of our orders too) it’d be great to have a look at!

Enjoy your weekend, and please let us know if you have any questions.

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@Bryce Yeah that’s a neat job. Not mine, despite hinting they needed me in Brazil to help I never got there :grinning: I just designed the hardware and liased with PCBcart, the fab house in China. I could have written the firmware as well but they had their own engineers for that.

Here are two of their promo documents that give some idea as to what they are for

Lite - Catalogo Saneamento (Virtual 1).pdf (2.8 MB)

As you can probably determine from that PDF document they are into water management and yes the modules are essentially PLCs and it’s a 24v system. All IO could read up to 50v, digital was isolated, 4-20mA IO, Ethernet, RF and GSM connectivity, yada yada. Every one was an Arduino-compatible board, the slaves all had ATmega328 CPUs and the master an ATmega256. All talking via an I2C bus running along the DIN rail.

After that I designed a stand-alone data logger for them.

And recently we were talking about another project but I don’t think that will happen, suites me as I’m happy tinkering with my own projects.

I’ll post some pics when I get the new Quub boards, meanwhile here are 3D renders of both sides.

I’ve never been a fan of white solder resist but saw some recently that looked good so thought I’d give it a go.

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Still no boards, shipped two weeks ago, probably on the proverbial slow boat :grinning:

Meanwhile here’s the schematic of this CPU board.

CPU-schem.pdf (121.4 KB)

I can of course still make mods so if anyone spots an error or has an idea for a change let me know.

Rob

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The slow boat from China has finally arrived. Six rev 2 PCBs, just got in and I can already think of a couple of improvements :grinning:

I haven’t ordered any parts yet so can’t really populated anything except the Adafruit module and a switch I had in stock.

I’m working on a couple of prototyping boards now so I can at least get some useful hardware up and running. The freight from PCBway can be more than the boards if you only do one design so I will get 3-4 ready and do them all at once.

The first proto board is designed to play with hardware plugged into the side of the base PCB.

Then I’ll do one to stack on top, plus I need a 4-to-1 relay board to help me control my solar arrays so that’s in hand as well.

I may need to control 12 PV panels so these can be ganged to control up to 16 relays in lots of 4.

That’s all for now.

Rob

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Hi Rob,

Glad your mail finally arrived! The model doesn’t look so nice but the actual white boards in the photos look slick. So glad the days of only green PCBs are over.

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Yeah I’ve never been a fan of white PCBs but these do look good in the flesh.

Green is so 80s eh? :grinning:

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Looks Amazing Rob!! What were you using for those two inputs? Looks pretty interesting :smiley:

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These are the two terminals

https://ihiconnectors.com/IHI-90c-high-current-pcb-terminals.htm

Model B2A9-PCB, 4th one down the page.

I suppose I had better make sure I can get them before I commit eh?

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Siiiick connections, the different screw types are something different from the normal screw terminals as well, almost $1 per terminal though!

Yeah thats a good question, do you grab the components before the PCB or at the same time usually?

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I’m an R&D type, I like designing but not manufacturing, so I hate sourcing components, as is witnessed by the fact that I don’t have any for the CPU board :grinning: So I tend to put it off. In the case of the CPU board however there is nothing unusual that should be hard to get so I’m not worried, but these terminals are from a company I’ve never heard of so it makes sense to order a few up front I think.

Keystone make something similar that’s available in all the usual places so I wouldn’t be worried about that, but it’s only good for 30A.

In general I search on Octopart, if a component is in stock at 4-5 suppliers I’m happy to use it, if not I try to use something else.

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Hi Rob,

Thanks for the pointer on Octopart! My designs are super simple for now, but sourcing has always seemed daunting to me, there’s a million options for each part in my design on Digikey, so which to pick? Seems like picking an available one should be my priority in the future.

When I finally get a PCB design that works and solves a problem, I’ll stick it here for sure.
-James

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Hi James,

Yeah sourcing parts is a pain, necessary though.

I look forward so seeing your design(s).

Rob

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