Stalled Iris 16 - RGB Vandal Button

[iFreilicht]

Learning from mistakes.

So today I had a bit of time and wanted to complete the BOM that I already started working on. This uncovered a very dumb mistake that I've made previously: I didn't finish the BOM right away. The problem there was that I didn't check whether the exact variant of the board-to-board connectors I wanted to use was available to buy. As it turns out, it isn't. This means that I have to use a different variant with two bosses that turned this

into this:

Whoopsy daysie, that's not good. So I spent the better part of the day reworking all three PCBs, two of them are finished now. What an unnecessary hold-up. I also tidied the schematics up, they are much nicer to look at now.

 

[ricochet]

Luv'in these informative updates! You definitely will be a PCB BOM expert when all said and done! Looking great!

 

[HeroXLazer]

Sure is. Didn't want to invest thousand or more into a professional CAD package, and after a bit of learning it works quite well.

Do you have an update yet?

 

[iFreilicht]

Not right now. I've been cleaning up the schematics and finalised the PCBs, including the advice that @hardcore_gamer gave me, but nothing that's worthy of an update. I wanted to order a few prototype parts but that'll have to wait until I get my tax ID, so now I'm mainly prepping all the parts for a first prototype run. If it works well enough, I might let a few lucky people get them for testing, but I won't promise anything until I'm somewhat confident that everything works as it should, and for that I need to make the firmware first, as well.

 

[iFreilicht]

HDMI Cable dismemberment

Sorry for the lack of updates, I want to prototype stuff before putting a first prototype run out (especially the oscillator circuit), but I'm in a weird limbo-state right now where I can't order as an individual anymore because I've already submitted the base capital and inventory lists to the tax office, so I couldn't get tax returns on stuff I now bought, but I can't order as a company either because I'm still waiting for my tax return ID which is required by some shops (especially element14 and digikey).

I was also on holidays from Christmas until Saturday and had to fight a small flu until today, so I was somewhat limited in the stuff I could actually show updates on.

But, today I've got a little interesting bit to share. Not really progress, but gained knowledge. So if you don't care about technicalities, you can safely ignore this post. I got one of those HDMI cables from Amazon Basics and dismantled it. Here's the schematic I've drawn up:

First of all, I found out that the colour coding of HDMI cables is NOT standardised. This means that these colour codes will only hold true for the particular cable I bought and might even change between batches if the supplier of the cable changes.

The thick blue lines represent separate wires being in a separately shielded part of the cable, which have quite unique colours:

We can see here that this particular cable supports Ethernet. How? Let's show that as well:

Image courtesy Blue Echo solutions.

As you can see, An HDMI cable with Ethernet is not only using separately shielded wire pairs for the four TMDS signals, but also for the HEAC signal. For this application, I'd actually have preferred a non-Ethernet cable because the non-shielded wires are a bit thicker in some cases, so a higher current could've travelled through them, but I had a free position anyway, so I now ended up with the (hopefully) final I/O spec on the micro HDMI connector:

You can see a lot of ground connections, but most of them are not supposed to carry any power, they are just ground references for the shielding.

Most notable are the grounds on the three HEAC circuits (power ground) and on P5 and P6, which are reserved right now for future use. As I explained in a previous post, 5 GPIOs is the maximum I could get from the microcontroller I'm using, but a potential 22mm version or even just a later revision with more tightly packed innards might be able to get 7 out, so I'm preparing for that.

 

[ricochet]

Enjoying this thread immensely.

 

[HeroXLazer]

Yes, there's an update, maybe the begging helped.

 

[iFreilicht]

Yay update, maybe the begging helped.

Maybe a little I don't think I would've normally written an update about this, but apparently you peeps like that stuff. Maybe I'll do more of these conceptual updates in the future to help understand why certain decisions are being made.

 

[ricochet]

Maybe a little I don't think I would've normally written an update about this, but apparently you peeps like that stuff. Maybe I'll do more of these conceptual updates in the future to help understand why certain decisions are being made.

Please do! I have actually learned a lot and what I don't understand I am forced to google and research. Your write ups and build logs are much appreciated. Plus, it is fun to be part of a product development from the very beginning.

BTW:
I have decided I will be drilling the 16 mm hole for this switch on the much thinner top panel instead of thorough that thick aluminum face-plate on my Silverstone ML06B-E case. Directly above the power button symbol on the face-plate in fact.

 

[iFreilicht]

Great to hear!

I have decided I will be drilling the 16 mm hole for this switch on the much thinner top panel

How thick/thin is that panel if I might ask? Also, maybe I'm seeing this wrong, but wouldn't a button in the top panel directly above the power symbol completely obstruct the ODD slot? And, isn't the top panel the only one that can be removed?

 

[ricochet]

Great to hear!



How thick/thin is that panel if I might ask? Also, maybe I'm seeing this wrong, but wouldn't a button in the top panel directly above the power symbol completely obstruct the ODD slot? And, isn't the top panel the only one that can be removed?

Yes, I am a dummy... I never thought about having to remove the top panel! Didn't care about the ODD though as I don't use one. Damn. Plan B... left side panel through the grill then.

 

[iFreilicht]

Well it won't be as problematic because you can disconnect the cable from the switch itself, so you can lift the panel up a little bit and then disconnect it completely without having to uninstall the switch.

 

[ricochet]

Well it won't be as problematic because you can disconnect the cable from the switch itself, so you can lift the panel up a little bit and then disconnect it completely without having to uninstall the switch.

That's very true, the ole' gray matter failed me there... that was actually my original reasoning/plan behind the top panel location... fully taking advantage of the switch connector. Though now after mulling over using the left side panel instead I realized that I can simply cut a hole (expand) at the two (2) audio IO ports or at a single USB 3.0 port as the entire audio/USB 3 IO panel is now completely defunct (I removed all the wires).

 

[HeroXLazer]

I'm just making sure 16mm is the diameter of the hole, right?

 

[ricochet]

Just making sure 16mm is the diameter of the hole, right?

Thus far, yes.

 

[HeroXLazer]

Thus far, yes.

Thanks for responding so fast and I always thought it was diameter but had a little doubt.

 

[iFreilicht]

@ricochet is correct. The button itself is actually a little smaller than 16mm, so it fits through such a hole very easily. This is always the case with buttons like this. A 12mm vandal switch is one that can be installed in a 12mm hole, not one that has an outer diameter of 12mm. It's easier for users to drill a 12mm hole than to drill a 12.2mm hole

 

[HeroXLazer]

Keep in mind that my button won't have enough power to power those strips. Absolute maximum power output on each GPIO is 50mA, which is plenty for a single dome-head LED as they appear in front-panels, but by far not enough to light a strip like this.

You could go with an Arduino with an RGB LED shield and mount that somewhere where it fits. In the LZ7 you could stick it in place of one 2.5" drive or onto the side of the PSU maybe.

I just realized, what is the connection on the button?

 

[iFreilicht]

It has a micro HDMI connector.

 

[HeroXLazer]

It has a micro HDMI connector.

So, then do we splice to 2 pin on motherboard?