Hardware Recomendations

Archive - Mycroft Project Picroft
22

You where prob given a design spec and did the best with what you where given.

I only wrote what my opinion was that for me a finnished Mycroft II had very little appeal.
I wondered generally with alternatives avail and at a expected price point if generally the appeal would be narrow.

It was just going the DIY root myself where some really simple kit forms just don’t exist. When you find something that doesn’t exist when there seems to be a market, it makes you wonder if that is a better option.

But yeah more modular that it isn’t just a single Mycroft II but a line of a base with upgrades that helps fit more pockets and choice.
I went on a bit of a purchase spend, but much hasn’t arrived and would have more specific info on the kits purchased.

I found 4" pipe annoyingly tight and problematic whilst 110mm a metric format was a perfect fit, think 5" is next US but it was just how to do a puck without much gear so the S-pipe design came to mind.
Its just an extremely low cost engineering material that was sourced because its round but its validity grew on me :slight_smile:
I should of been able to tell you about those tectronic BMR speakers if its just sales pitch and if stealing the google form of a central pimple to create a ripple over what might be a first logical assumption that you needed a shapeform to further disperse over the horizontal axis of a single speaker.
I wondered about Pi4 thermals which I have found those ‘armour’ case/heatsinks with a just a little air flow to be great.
If a bass reflex was pointless or not…

I meant to have a few photo’s and write up by now but the coronavirus has had much effect with deliveries even if well, .

I was supposed to demonstrate how a tube form and some discs could be solvent welded into product that creates a customisable stack that went from bluetooth speaker to the full pan-tilt cam/screen robot AI.
I have some lovely carbon fibre effect vinyl for the ‘wrap’, the 4" tube that turned out just slightly too tight for respeaker 2 and some cone sizes whilst the 110mm, and various bits seem to be in coronavirus limbo.
So yeah still very much at an initial stage myself.

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23

PS some of my shopping has turned up and during the wait some of my shopping I have found much cheaper elsewhere.

The 4 mic respeaker clones are extremely cheap.


2 Mic module is prob not worth the few $ saving apart from the speaker out that is good to get you going.

I am waiting for quite a ‘nice’ usb dac but still waiting for the el cheapo PCM2704 usb which supposedly sound pretty good.

My Sure Electronics not 100watt Class-D amp turned up .


What a quality module that is and I will be using the mute and standby pull to gnd pins on it.
It really is excellent quality but the extra $20 dollars over an el cheapo TPA3116 is sort of hard to justify.
Its 100watt into 2Ohm with 10% distortion I run from the max of 24VDC and get 48watt that is pretty damn clear and boy is it loud.
12Vdc prob would be OK it would halve the wattage but ears work on a decibel scale not linear so it doesn’t sound half the volume.
I rarely have the volume above a third with 12v a guesstimate 50% volume would prob be your norm.
The Pi 3.5mm is a strange beast and on average isn’t that bad sounding then you will get a track where you will wondering if the amp or speaker is dying with the distortion on the vocals.
Dunno what it is the method of recording, frequencies in the track or sample rate, VBR or CBR but anyone listening will cringe.

So it wasn’t the el cheapo TPA 3116 and now understand why the Pi gets such bad rep for hifi audio unless you use a dac, but those are cheap and plentifull also and in comparison sound sweet,
PCM2704 usb stick or board and TPA3116 all can be got for $6-8 apiece!

But must say My Sure Electronics Wondom board is a quality piece of kit, so no sulks about its purchase due it really being the Pi.

I presume the respeaker 4 mic clones are just treat as respeaker and grab there git hub drivers.
I have an respeaker on order as hadn’t noticed the availibility of the clones.

My 30watt 8cm speaker is a great compliment to the Amp and copes & sounds well produces a good full range with quite good bass.

Still waiting for the Techtonic MBR horizontal speaker is like the wondom and justifies extra.
Its 20 watt in comparison and quite a bit more than the good quality Visatron, dunno on that one yet. The quality of the Vistron and 10 watt more means this might be worth it or not.

https://uk.rs-online.com/web/p/speaker-drivers/8765241/

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@StuartIanNaylor That are some nice tools you are getting in!

Keep us posted on how they act / perform.

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@j1nx I have prob gone too ‘nice’ as what I have been surprised with is the cost and quality of these cheap class D amps that are mega efficient and give off little heat.

They are dirt cheap on aliexpress ￡3.21 and honestly they are not that bad.


DAC ￡3.05

Speakers I haven’t tested apart from more local £10 vistron 30watt to go with the above but that is my top budget pick that will blow the knickers off many expensive usb speakers.

That Sure electronics badly sounded Wondom is pure quality and build with a PCB that you only find on the insides of very high end gear.
But my findings are there are some ultra budget gear that is amazingly close and fit for purpose.

The only other thing I have been playing with is isolated usb hubs as it can be really annoying for the power to feed back so your Pi never reboots properly.
The isolated ones available unless expensive are reduced speed
I have been a bit hacky here but since its all from the same source supply…

£3.88

Hub to Pi I only use 2 wires D+/D- and just solder external 5v or use one of the ports to feedback 5v.

I have a 4 mic respeaker but if someone fancies having a punt on the cheaper clones.


It certainly looks identical and £12.88

Its actually pretty amazing and much fun what you can do on an extremely low budget from pizero, pi3A+ to pi42b you can make an array of wireless speakers to AI that have an extremely meaty volume for little £

I am going to have to go on a budget speaker crawl and see how the < £4.00 perform but the £10 30watt visatron cone is absolutely mighty when in a enclosure.

But for just over £6 you can get a resonable amp+dac that makes the a pi 3.5mm output sound like dirt and rumble at quite a volume. Then again it just does but those dacs like the amp are good for purpose, they are not audiophile but sound good.

Like they are not as good as my AKG Y50 phones and my SA9023A ES9018K2M headphone amp/dac combo but the difference to the difference in price is actually outstanding.
Prob been enjoying the budget buying more as its very cheap, quite good and its been quite fun.

The deliveries are hard work at the moment but externally coranavirus is approx 72 hours so three to 4 weeks from the other side of the world is probably better than a couple of days somewhere close.

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@j1nx Might of found an inbetween the ultra cheap tpa3116 and the Surelectronics.


Stereo or bridged mono but also has a mute and the caps look audio grade.
I am so out of the loop nowadays as used to be able know with a glance if the rest are tants, ceramic or polyester.
It was £9 so will let you know :slight_smile:
I like having a mute input as basically going to do a circuit with gpio to unmute when running so no pops clicks or farts and also no hiss whilst not playing.

The circuit and gnd plane on the double sided board looks like it might be better, what the design is like…

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27

Looks nice, but me personally am looking for a proper (USB) soundcard - including Amplifier. On the cheap of course. I’m Dutch :wink:

The 3.5 jack on the Raspberry Pi is, well… Crap!

Not looking for a HAT as I would like to support it for non RPi builds as well.

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28

I don’t bother with a sound card the PCM2704 DACs are so cheap auto detect and become your USB amp preamp.
You can get better DACs but they are like a huge improvement over the Pi which is very weird as mono which is no problem but you will get a track and not sure what goes on if sampling rate VBR or CBR but wow you will think your amp is on its way out how much it farts in mid range.

I have actually been really enjoying the cheap purchases as its for a mono satelite and its amazing how good they are.

29

You have some links for me, just like your posts above?

You know your stuff if it comes to that. Looking for a proper board/device that can give me better sound quality.

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The one I listen with my AKG Y50 headphones is good and still relatively cheap.
https://www.ebay.co.uk/itm/USB-HiFi-Sound-Card-OTG-DAC-Decoder-Amplifier-SA9023A-ES9018K2M-Fever-PM-P8S/143509854403
But with the amp and speakers prob wouldn’t bother as to be honest the difference is not all that much via the headphones but by the amp its minimal, in fact lost as you need a really high end amp.

That is why I have been enjoying it as those really ‘dirt’ cheap are actually quite good.

The tectonic Balanced Mode Radiator,round, 30W, 4ohm £11 from RS turned up and just going to have to play with that thing.
The magnet and weight for size is absolutely huge on that and going to have to play with enclosures with it.
Its not as sensitive as my other but also how the sound comes out is just head twistingly weird it could well be perfect for a google style puck but haven’t quite yet worked out best options or got an enclosure for it but the full range higher end is great but so needs an enclosure so can not say.
I am going to have to weigh it as it feels heavier than 685g but maybe its just that its such a solid lump compared to the 280g Visatron FRS 8 I got.
Sound quality and volume they are prob about the same no MBR tech for the visatron but for same cone size its generally half the size of the Tectonic and that might be a criteria for or against for some.

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Hi, I am very happy that I found this great project. I don’t like the other available assistants because of the privacy issues. Sadly Mark I is out of stock, and Mark II isn’t expected this year. So I want to build a “Mark II” on my own. Is the Mycroft Mark II - Rpi Prototype Hardware still up to date posted on Github by Derick? Can I use these components from the BOM? I want to change the Raspberry 3 for a more powerful Pi4 with 4GB RAM. Can I use the newer PI4 instead of the listed PI3? Is the Seeed Studios Respeaker Mic Array v2.0 still recommended? Or are there better solutions meanwhile? Does anyone know if Mycroft AI has changed some of the prototype components for the final product which will be sold later? What do you recommend for building a Mark II by myself? I have a 3D printer so I also can print an enclosure like Guhl’s modified version on Github.

I would be happy to get some answers that point me in the right direction for this project.
Thank you.

32

When using a RPI4 in the Mark-II RPI you should consider that:

  • some connector/ports have a different format and location compared to the RPI3 (e.g. RPI4 has Micro-HDMI, USB and LAN-ports have switched position, power input is USB-C instead of Micro-USB, etc.).
  • most important: heat dissipation - RPI4 gets much warmerhotter than a RPI3. I doubt there is enough room in the Mark-II RPI enclosure for a proper heat sink or fan. Maybe Guhl’s design has more room for that?
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Yep heatsink on a Pi4 is well needed, would never run without one.

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Hi @Tom74

I am running the “Mark-II” with almost all of the BOM components from the original BOM.
But I am using a PI4 (4GB) in it without any additional problems (and no heatsink).
The waveshare display comes with the connectors for PI3 and PI4.
The only thing you have to change is that you will need a USB-C Cable for the power supply.

I am not totally sure if I updated the STLs and Freecad file to may latest optimizations on Github but I will check that.

Actually the case is a little bit too low to fit the components (the mic array) perfectly it should be changed to make it about 3 millimeters higher.
And I only use “M2.5 Threaded inserts 3.5 mm OD x 4 mm” and only “M2.5x6 screws”
If you still have some time then I will update the CAD design over the weekend and update the git repository.

There is also and additional posting from me on how to build the software stack, especially the GUI.
If you need any help - ask!

Have fun - Guhl

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I think a sticky topic with a spreadsheet of all tested/supported hardware would be awesome. Or even just a sticky link to a git repo with this information including setup notes.:grin:

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Hello @guhl

Thank you for the information. It would be nice if you could update the CAD designs.
Yes I have time and meanwhile I can switch to the software part and start to install the needed software stack on the PI4.

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Hi @Tom74,

I did update the freecad file and the STL-files and updated the original posting and the git repository.
I think it is obvious that you need to rotate the STL-files before printing them. (The angle of the front is 6° btw.)
For the front there is a STL-file that includes support structures. In general I printed all the files without generating additional support material.

Have fun - Guhl

38

@guhl

Prob one of the best recomendations for low-end audio is 2x I2S mems microphones.
You have done such great work with the 3D builder files wondered if you could add them to your BOM.
Being wired they are far more flexible but a mouting bracket would be a great addition.

Real easy to set up and they are clock synced to the 3.5mm.

With a Pi3A+ they prob make the best budget base and if on a really tight budget the lower price circular I2S boards work with the above adafruit software driver.

Touch less sensitive but practically as good but diferent mount.