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ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker
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ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker

by EkDor on Sun Jan 20, 2019 4:40 am

Hi All,
I am working on a light sabre project. I have not purchased electronics yet, partly due the ItsyBitsy being out of stock and shipping to Australia is hideous so want it all in one go.

I am enquiring as to whether anyone has tried or knows if the "ItsyBitsy M4 Express (3800)" can happily run the "4 Ohm 3 Watt (3968)" along with perhaps 3 or 4 "NeoPixel 5050 RGB (1655)"? Also I am thinking of adding a small vibrating moto to add a physical layer to the effects. Not decided on that. I expect it to end up a subtle vibration to correspond with the idle hum of the audio. Yes more power load but I don't need it to have a long run time between charges.

I have read many bullet-point spec sheets today. Can anyone confirm if the ItsyBitsy can charge a polymer cell? Or do I need a breakout charger board for that? Does anyone have advice on a suitable battery for such a narrow project? I haven't looked into those yet.

Thanks for any advice and suggestion.

EkDor
 
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Re: ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker

by adafruit_support_mike on Mon Jan 21, 2019 7:16 am

The ItsyBitsy can't handle enough current to drive a 4-Ohm speaker by itself. You'll need to add a power amplifier like the PAM8302:

https://www.adafruit.com/product/2130

NeoPixels can run from the same power supply as an ItsyBitsy, and most of our NeoPixel devices will run from a LiPo.

The ItsyBitsy doesn't have a built-in LiPo charger, but you can add one easily enough:

https://www.adafruit.com/product/2124

LiPos come in all shapes and sizes, but for a light saber build, a cylindrical one would probably work well:

https://www.adafruit.com/product/1781

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Re: ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker

by EkDor on Mon Jan 21, 2019 8:08 am

Great! Thank you for that info. I’ll at it to my project notes.

EkDor
 
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Re: ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker

by EkDor on Mon Jan 28, 2019 4:55 am

In regards to the ItsyBitsy M4 Express. It looks like there is a pinout for powering it without using the USB Micro. Is there also a pinout for the data for the USB Micro socket? Due to the confinement of the project I am designing I can't really fit a USB Micro cable and it's plug. Well I could push my limits to get a trimmed down one in. I would rather solder a cable directly to the PCB but the pitch of the connected is beyond my soldering skills. FYI I would like to solder the other end to a custom PCB that will contain a USB connector for charging and re/programming and also serves as mounting point for my LED's.

Thanks.

EkDor
 
Posts: 26
Joined: Thu Nov 17, 2016 4:01 am

Re: ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker

by adafruit_support_mike on Mon Jan 28, 2019 5:04 am

The micro-B jack is the only place where the USB data signals are connected. In theory you could remove the jack and connect wires directly to the pads, but that is tight soldering.

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Re: ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker

by EkDor on Mon Jan 28, 2019 6:58 am

Ok thanks. Pitty though. I’ll try slimming one of my spare cables and see how small I can make the hole for it. I looked at one of these connectors on a scrap pcb and it really is a fine pitch. Might try it on this board. Never know I might surprise myself.

EkDor
 
Posts: 26
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Re: ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker

by EkDor on Tue Jan 29, 2019 1:48 am

In half sleep last night it occurred to me that Adafruit (AF) being open source I could modify the ItsyBitsy M4 Express board to break out the USB Data pins and use a prototype PCB service. Then buy the board from AF and transfer the components. I think that would be easier than trying to solder the wires in. The more I look at them the less I think I can do it. That way I get what I need and AF gets paid for their open source. Win win... Also I've wanted to try out Eagle and get a PCB printed and populated. Seems like a good start since it's a small change. Worth a try.

EkDor
 
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Re: ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker

by adafruit_support_mike on Tue Jan 29, 2019 4:11 am

That's worth a shot, though transferring the microcontroller might be a challenge.. it's a QFN package (Quad, Flat, No-leads), so you'll need reflow capability.

The design files for the ItsyBitsy M4 are here though:

https://github.com/adafruit/Adafruit-It ... xpress-PCB

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Re: ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker

by EkDor on Tue Jan 29, 2019 4:18 am

Yea I have reflowed in the past. Seen lots about it from various sources including AF itself. I figure the reflow of the chip will be a bit easier than soldering wires to the tiny solder pads. Also i get to start learn something new.

I have already started editing the board. Bit more to learn but getting there. I'll post what I have done here, when I have finished, for some inspection by anyone willing to check/advise/etc. I will no doubt break some rules etc.

Sorry if this isn't place to be posting this.

Thanks again for all your advice.

EkDor
 
Posts: 26
Joined: Thu Nov 17, 2016 4:01 am

Re: ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker

by EkDor on Tue Jan 29, 2019 10:44 pm

Hi, I have spent a few hours learning to use Eagle. So on a test file I made all the changes I wanted to make. Once I had completed that I started fresh with an untouched project copy from AF. I'll list the things I did to the ItsyBitsy M4 Express project.

In the Schematic Editor
- Removed the USB Micro part. Put in it's place a 4 pin header footprint.

In the Board Editor
- Removed the two vias that were located under the USB part.
- Put the 4 Pin connector in the space previously used by the USB part.
- Reconnected the traces as per air-wires.
- There was one short unconnected ground trace that was automatically ripped up by removing the USB part.
- Moved the bottom layer trace to avoid being drilled through by the new pin header foot print.
- Added labels.
- Removed the indent in the board edge routing.

I was very careful not to make unplanned clicks within the work area and are pretty confident I have not made any changes I didn't need to. If there is an issue I would predict it to be related to the small unconnected ground trace that was removed when removing the USB part.

If anyone is willing to take a look and see if I have made any obvious errors; it would be greatly appreciated. I will in no way hold it against anyone who does a check and fails to detect a flaw.

Bellow I have attached the project which includes the original master project; for convenience.
ItsyBitsy M4 Express - USB Pinout.zip
(525.32 KiB) Downloaded 11 times


Thanks in advance.

EkDor
 
Posts: 26
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Re: ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker

by EkDor on Mon Feb 11, 2019 3:02 am

Well that idea might be dead for me.

I just got email of new stock of the ItsyBitsy M4 Express in stock so I thought I might get back onto the PCB and get the first attempt underway... I thought JLC would be a good choice. After making some tweaks to the top silkscreen and exporting gerbers and uploading and filling an order for 5 parts for $2.82 AUD and then proceeded got a whopping $61.36 AUD shipping added... No way is that possible. The shipping from AdaFruit wont even be that much. Based on a previous order I expect it to come to about $35 AUD, although I'll add extra so might be higher. Maybe Australian shipping has gone up across the board since then. But I can kind of justify by making a bulk order for a couple of projects at once with AdaFruit but I can't do that with the PCB manufacturer.

Does anyone in Australia have any experience with this and some advice, solutions etc? Other affordable PCB Manufacturing in Australia. I'll take a look obviously but if anyone local Oz can chime in would be great.

Otherwise I'm just going to have to have to find a hack way to get a USB to fit... I guess I just have to make project a bit longer than wanted. Still I am disappointed as I was kind of looking forward to this. Was also planning to do a couple of other boards too. But adding those won't justify that much on shipping. Ridiculous.

EkDor
 
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Re: ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker

by adafruit_support_mike on Mon Feb 11, 2019 4:58 am

Check with Dave Jones over at the EEVBlog:

http://www.eevblog.com/

He's an EE from Sydney and well-known in the world of YouTube electronics bloggers. He's done videos on having his own boards fabricated (usually from shops in China), and will have plenty of good information about sourcing components in your area.

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Re: ItsyBitsy M4 Express and 4 Ohm 3 Watt speaker

by EkDor on Mon Feb 11, 2019 11:27 pm

I know him well. Followed his channels for years.

EkDor
 
Posts: 26
Joined: Thu Nov 17, 2016 4:01 am

Please be positive and constructive with your questions and comments.