Announcing the ORDuino !

[IPvFletch]

If the MicroSDcard slot is designed for the SDcard to float over the chips, how would you flushmount it and let the chips land on the aluminum to be used as a heatsink? Or is the MicroSDcard slot going to be on the BACK of the board? Also, how would you swap it out if it's hidden on the underside smooshed between the aluminum heatsink and the PCB itself?

[Oli]

[deleted]

[Stephen Wright]

I'm interested! Count me in for one. Being a C# developer I would also be interested in a future .Net micro framework version.

[dzach]

i went to the webstore and could find no mention of this design anywhere, only a regular arduino board.
So it looks like they got in over their head and bailed. I wonder what happens in that case? did the money go back to the backers?

I had this same discussion in some other forum a couple of weeks ago. They want to go ahead with a multi-thousant $ device but the creators don't have/want to finance even the prototyping boards for the project, in other words they seem to want to pass all risks to the public. I believe it makes a huge difference if the project is proven, i.e. there exists a functioning prototype that's been tested and gone through a number of revisions before it hits the market.Trust is built mostly on hard evidence, not intentions. Like they say it in Missouri: "Show me!"

[frob]

... I think it should offer holes for the stepstick / polulu, but also have SMT pads coming off these holes for a new design of board that uses a castellation array on the edges of the board. It would keep the normal holes for compatibility. That way the new board could be easily hand soldered into place and two large castellation pads could be used at each end for proper heat sinking to the motherboard, something the current designs lack (proper heatsinking through the pcb). It is unlikely they will ever need to be removed if they are the current limited variety...

Yup i though of that, i've done a few modules already using castellations - which i really like- no flaky , costly, and space consuming connectors - and you dont pay for them when you dont need the option.
The problem i see with castellations is it only works if the "on-board" version was never populated with parts, unless you have a means of desoldering those parts - in the case of the QFP package with lots of thermal vias underneath to a heavy ground plane, that is very difficult to do without a hot plate and IR/ hot air rework station.
I was looking for a way to support a surface-mount strip header or socket for the pololu's which could double as a castellated SMT land, but the trouble with those is the single row SMT hears use zig-zag style bent leads which waste a lot of board area and don't leave enough room for the IC and parts in between. and they're significantly more expensive than plain 0.1" strip headers.

Considering that the actual use of that option (installing pololus to replace a burned-out motor driver) may actually be quite low to nil, i am ok with having through-hole pads for that.
I may extend the top pad outward and make it rectangular to accept a castellated module later, as you suggest.
i will make the pad hole barrels fairly snug to the pins with minimal pad on the underside to reduce the risk of shorting when a heatsink is used on the back. When installing pololu's, I recommend installing the female sockets on the pololu's and the male pins on the board; When pins are installed along with a heatsink i would recommend putting kapton tape in between, and sanding down the pointy end end of the pins first - then assemble the board to the heatsink, carefully insert the pins, check for shorts with a meter, and solder the pins from the top side. a little tricky but not too much so.

- I think it might be worth considering including atx power supply sockets. They are used as the power source in most builds and modifying connectors etc is a real pain.

I agree, especially since this allows me to power the board from the standby 5V rail and connect the remote power on-off control to an i/o line and monitor the power good signal. also the remote sense terminals will be properly terminated. The connectors are inexpensive - The only downside is the connector takes a lot of space ( the board will have to get bigger) and is only available as through-hole with very thick / long pins. I wish there were a SMT version. I considered making a custom lead bending jig to make it into a SMT connector but its seems like more trouble than its worth.

- I am slightly skeptical of the ffc type connectors. I know it would be a tidy solution and in principle a good one but they are not really designed for high currents. I guess we'll see. Costs on custom lengths of this ffc are what I see as another problem. I don't really see a big problem with normal low temperature / silicon cable provided it is routed correctly. I have another solution that I have PM'd you about

. I have to go back and reread your PM on that - The FFC cable is available in standard lengths like 8", 12", 18" etc from Digikey and in stock for a reasonable price, $5-10 typ in small qty. Molex will custom make them for me even in smaller qty (like 100 pcs) for much less than that per piece price, typ less than $2, sometimes less than $1. Depending on the source and pitch, they are rated 1-3A per conductor. i am using 30 conductor , with 4 used for signals and 26 for power, thus 13A should be fine. probably more. Also remember once target temperature is reached the current is cycled on/off at a pretty low duty cycle, so even if a little heating happens in the cable, it shouldn't be significant. What i'm more worried about is the plastic material of the connector body, and how it might degrade or weaken over time, being mounted to the hot plate. that's partly why i like having it mounted backward and the cable sandwiched between it and the carriage so it cant accidentally pop open in use. I agree there isn't any major problem with using regular cable, i just find this option neater and a little more elegant so i thought it would be worth trying in the prototype. Eventually i envision replacing all of the cables with FFC, so i though trying a test case starting with the most challenging section was a good idea.
The connectors are cheap and don't take much space, so if its not popular or doesnt work well, i just wont install them, or leave them out of the production version.

Imagine having a single board that means that you can buy Barts kit, the ORDuino board for less than $150 and an ATX power supply to have it mostly complete. This would be a real winning formula. Very exciting stuff

Thanks !

[dzach]

Generally when we refer to PCB layers we're talking about copper layers, not the laminate/prepreg (FR4)

Some 25-30 years ago, I was doing my "multilayer" hobby PCBs by stacking single sided PCBs underneath a top double sided one. I guess things have changed since

I got my RAMPS from RepRapWorld, he is located in the Netherlands (ebay too). Best price, yes, and good service too.

[frob]

If the MicroSDcard slot is designed for the SDcard to float over the chips, how would you flushmount it and let the chips land on the aluminum to be used as a heatsink? Or is the MicroSDcard slot going to be on the BACK of the board? Also, how would you swap it out if it's hidden on the underside smooshed between the aluminum heatsink and the PCB itself?

All the parts are on the top side, the back of the board is completely empty of parts.
The heat generating parts on top are thermally coupled to the back side of the board with a grid of vias underneath large thermal pads on the bottom of the parts. When i'm closer to final layout i'll post some renderings which should make it easier to see how the SD card is accessed.

[frob]

The LCD and uSD are two things that I feel quite strongly about, primarily because it will create fragmented firmware versions (with uSD support, without, with LCD support, without). For those that want everything else, including the bathroom sink, the standalone arduino platform is ideal - they can expand as they please. Truthfully, for those with LCD's / uSD, who has actually used them for a practical purpose? For everyone else, it will simply be an increase in board size and cost (albeit a small increase).

I hear what you're saying and i mostly agree with you. On the other hand, some extras are so cheap and easy, i don't mind throwing them in for free - i honestly see little downside to adding a $0.50 connector for an optional LCD that needs ~ 1/2cm of board real-estate. maybe i'll drop it on the back side of the board if space is getting tight on top. If no LCD is connected you can call it a "free expansion connector" instead
Edit: i forgot to add, about code fragmentation, its not automatically the case. The updated firmware should work fine whether or not the LCD is in place. same with the SD card. The changes to the code a quite minor.

In my view, the primary goal is to optimise to a single board and reduce cost - so we're left with a compact, low cost, elegant design that together with the Hadron will make the total build far more 'plug and play' and less of a rats nest of wires.

Exactly right.
Sometimes i can get a little carried away with my enthusiasm for technology.
I consider a first prototype "fair game" to experiment with new parts and extra features that may or may not make it into the final production version.
Its always safer to cut stuff out than add new stuff in, at the last minute when ordering production boards.

Obviously though, this is Frobs build first and formost and I support his decision either way.

Well thanks but i am now considering this a community project - so i wont overrule popular consensus without a *very* good reason.
At the moment it seems more people are in favor of the LCD than not, so i will include it in the prototype.
On the other hand, if the wind changes direction and more people are vocally against it by the time i'm ready for a production batch order,
i will delete it, or at least not populate the parts if it takes insignificant space.
Isn't democracy wonderful?!

Cheers
Frantz

[Zat German]

Please don't cut LCD or SD card, both of these are extremely appealing to me.

I do not agree that the inclusion of either will cause fragmentation. Firmwares are open source. Someone can always come around and implement the functionality in the firmware they need if it doesn't have it. If they do not have the skills to, they can always put up a bounty to get it done.

[Enraged]

I'd like to keep the LCD and SD as well.

Any timeline on a first batch of these boards? With Hadrons going out in around a month, I'd love to get one of these rather than buying a RAMPS setup and then switching.