Arduboy Mini [Kickstarter Funded!]

Where did you find the battery?
Also in Aus

Online at Metro Hobbies. You in Melbourne?

Thanks.
Yes.

3d printed case in!

Had to make some modifications because of the spray varnish closed some tolerances. @acedent you were right that’s all I can say!

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This looks so good! Cannot remember if I ordered… need to check! :sweat_smile:

Pre-Orders still open. Will be taking them off sale as soon as production starts. Which would have been this week, but I think I need to delay a few days to add reverse polarity protection which I know someone warned me about why didn’t I listen. My prototypes are more than $100 and I smoked one just by hooking up the wrong battery :frowning:

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:grimacing: :cold_sweat:
Good your testing found this now! I’ve released the blue smoke in exactly this way… it’s always frustrating… @Mr.Blinky’s suggestion was a diode.

Also, at least you can now centre the front LED… :wink: :traffic_light:

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I realized the LED in front didn’t get centered because doing so would take a lot of work adjusting traces only for a mm of difference so it’s just, there.

Spending the day looking at diode specifications to use here, if anyone has suggestion on what diode to use for reverse polarity protection on the battery would be much appreciated, thanks!

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You could use a schottky diode but a p channel mosfet would be better. Check out this
Reverse voltage protection video

you could probably use a FDN340P/PMV48XP but do check the specs on the datasheets to be sure.

Cuz the voltage drop right?

Is it just close enough to being centered but not quite there enough to upset my OCD :stuck_out_tongue_winking_eye:?

Yup. The battery will have a nominal voltage (that it spends most of its discharge curve at) of about 3.6V. You have a 3.3V LDO to provide power for the Qwiic/I²C connector. That LDO will have a dropout voltage requirement.

A Schottky diode will drop about 0.3V. If you put one in series with the battery, the LDO (and the rest of the circuitry) will get 3.3V. This means there’s no voltage to cover the dropout requirements of the LDO.

A MOSFET circuit with a low RDS(on) might give you enough output voltage to allow the LDO to output 3.3V over a fair amount of the battery discharge voltage curve (at least if the device(s) attached to the Qwiic don’t draw much current).

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@bateske,
I forgot that you already have a battery voltage drop through the MOSFET used for switching between USB and battery power. This will make it worse for any additional drop caused by reverse polarity protection.

Should be fine I’ve only seen .1 or .2 drop so shouldn’t impact anything but need to check.

Good news looks like I can hopefully reuse the mosfet for the battery protection. Added bonus this will be easy to test.

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oh, why didn’t I back this? :frowning:

It’s still available for preorder isn’t it?

Sure is!

https://www.arduboy.com/shop/mini

Coming off discount end of this week! Grab them now!

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I have an order in the pipeline. Looking forward to getting it. However, I like that you are trying to improve it still, so I can wait.

Free lanyards! *Random colors

I guess if the site is called X then it brings a double meaning to xposting.Cross-posting. Anyways, it kind of saves on community storage resources ;D

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