
OpenRex – Open Source Hardware Project - peter_d_sherman
https://www.imx6rex.com/open-rex/
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turblety
Great work on this, it looks like a great project. Right up my street with
open source. For me personally the price vs specs [1] just don't make this
viable, considering you can get a Rockchip board for half [2] the price and
with better specs. It's also pretty open source [3] too.

I'm really excited for the iMX8 though. It looks like it has much better
specs, and if they can remain as open source and hobby friendly as the iMX6
then I'm all for it, even if it costs slightly more.

1\. [https://www.voipac.com/#category1](https://www.voipac.com/#category1)

2\. [https://www.pine64.org/?product=rockpro64-4gb-single-
board-c...](https://www.pine64.org/?product=rockpro64-4gb-single-board-
computer)

3\. [https://github.com/rockchip-linux](https://github.com/rockchip-linux)

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cushychicken
I wish more OSHW boards featuring the imx6 gained momentum. It's a lovely
processor to work with, and NXP's documentation puts most vendors' manuals to
shame.

Plus, if you ever ship at scale, it's pretty easy to get your hands on a large
quantity of them!

~~~
joezydeco
I've been developing on i.MX6 for the past 6-7 years and it's been the easiest
Linux processor to work with out of the lot (looking at you, Renesas!)

And there's no shame with using a processor/RAM/eMMC combo on a SOM, either.
Doing the high speed DDR layout on 6 or 8 layers of PCB is not a task for
novices. Saving the low-speed interface work for a larger 2-layer carrier PCB
makes the project go really smoothly (just watch the EMI off those right angle
card-edge connectors!)

There are plenty of companies selling the IMX in all kinds of configurations
for really decent volume prices. TechNexion and Boundary have been my
favorites so far.

~~~
fest
I concur. i.MX6 not the fastest nor least expensive nor most power efficient
SoC but the documentation and wide variety of SOMs make it competitive for
lots of products.

I've designed it in a thermal imaging product, where it's 20 bit wide DVP
support came in very handy.

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bsder
Why not Beaglebone Black/Green/Blue? This is a real question.

TI's stuff is open. TI's manuals are awesome. It already exists. There are
user iterations that are different from the TI reference. The board is a much
cheaper 6 layer board.

What niche does this serve that a Beaglebone would not?

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johnwalkr
I use iMX6 because it has nice features for image processing, like compressing
camera input to H264 before putting information to memory.

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mntmn
We’re using a derivative of this, the TinyRex SOM, in MNT Reform (libre
laptop).

~~~
fest
I only wish the mating connectors had an alignment pins, those are a pain to
solder accurately when placed manually.

~~~
mntmn
Oh man, very true.

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tonyarkles
I'm a happy Fedevel customer. Robert does a great job putting together the
material. I haven't finished the course I bought, but I've gotten a lot out of
what I've gotten through so far. Definitely helped me "level up" on my PCB
design skills.

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ac29
Some of the PCB layer diagrams look pretty cool: [https://www.imx6rex.com/wp-
content/uploads/2016/02/OpenRex-L...](https://www.imx6rex.com/wp-
content/uploads/2016/02/OpenRex-L8-1182px.jpg)

Anyone know why they are designed this way? Very wiggly traces.

~~~
nyc
Typically those wiggles are for length matching on parallel busses. Since the
signals are clocked at a high speed, ensuring all the bits arrive at the same
time is crucial.

~~~
akiselev
Not just parallel buses. You can see several differential pairs as well, which
look a lot like the parallel buses except the pairs are routed much closer
together.

Differential pairs carry polar opposite signals so that any noise can be
canceled out by comparing the two. While parallel bus traces need to be routed
to 1/20-1/40th of a wavelength, the differential pairs need to be routed to
within 20mils of each other with impedance controlled traces (which depends on
distance to each other and other traces as well as material variability, hence
the tight routing).

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howard941
All other considerations aside IMO the Rex board is aesthetically a beautiful
board. For me that was enough to overcome the sticker shock.

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MeteOzturk
Is anyone aware of a similar open-source hardware project around camera
sensors image processing?

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sigmaprimus
I'm a bit confused with why the prices in the Web store are so high. Is it the
fact that it is open source driving the price up? Or is the Slovak
manufacturer just faced with high manufacturing costs? Would getting seed
studio's fusion pcb service to manufacture drive the prices down? Or Would
getting China to manufacture this be considered immoral some how?

~~~
baroffoos
The prices seem fairly in line with what you normally see for fully open
source boards. They cost a lot because of the low volume and huge amounts of
work that have to be done. For a regular board you just slap down whatever
parts you want but if it has to be open source you need to put in a lot more
work looking for parts with free firmware and spec sheets as well as writing a
lot of firmware yourself.

The GnuBee is an open source nas that is actually cheaper than everything else
on the market. I suspect because its a fairly simple device and the
proprietary versions are super marked up as well as the creator being located
inside Shenzhen

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m0zg
200 euro? That's gonna be a no from me, dawg.

