[Resolved] Omega 2 DOA or Power Issues



  • I just got my Omega 2 in the mail yesterday from the the Kickstarter campaign. I did not buy a power shield. Instead I am trying to power it off the 3.3v rail on my Arduino Uno, and the Arduino Uno board I'm powering off of a PC USB port.

    When I connect it this way, the orange LED lights for about 20 seconds and then turns off. My understanding from the Omega 2 getting started guide is that at this point I SHOULD be able to see a wifi network called Omega-B415 (last four hex digits of my device's MAC, from the sticker on the device), but I do not see it. Tried both with my laptop and with a "wifi analyzer" app on my phone.

    It doesn't seem like the shield gets noticeably warm to the touch after 10 minutes or so of being powered.

    In my photos you'll see some electrical tape on the power wires, but the connections are soldered underneath the tape and the tape is just to prevent them from shorting.

    I saw another thread about sloppy soldering being the cause of Omega2s being DOA, but I carefully inspected my device and I don't see anything sloppy or any pads being connected that shouldn't be.

    Is my device DOA, or am I just not powering it correctly?

    Update: the Omega 2 is just more finicky about input power than I would have guessed. I eventually was able to power it off of a 3.7v cellphone lion battery

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  • @Alex-Clark Pretty sure your Uno's 3.3V rail can't supply enough current. You need a power-source that can handle spikes of around 250mA to be on the safe side.



  • @WereCatf Ok, what about tolerance on the input voltage? Would two AAA batteries in series (3.0v) be alright? Would a 3.7v lion battery from a cell phone work?

    Should I try the 3.3v from an ATX power supply?



  • @Alex-Clark According to specsheet, minimum voltage is 2.97V and maximum is 3.6V. Even if your two AAA-batteries were totally full they'd just barely reach the minimum requirement, and for the li-ion battery you'd have to drain it to 3.6V or less first.



  • Update: I tried with an ATX power supply, jumpering the green and black wire so it would supply power while not connected to a mobo. I measured 3.4 volts between an orange wire and an adjacent black wire on the same connector.

    Powering the Omega 2 in this manner produces the same results as all the other methods I have tried, which includes a CR2032 (3.0v), two AAA batteries in series (3.0v), and the 3.3v rail from an Arduino Uno. The results are that the amber light lights up for about 20 seconds (this time I counted about 24 seconds in my head), and then it turns off. There is no Omega-XXXX ssid being broadcast that can be seen either by my laptop or my cell phone.

    Below is a picture of my setup. Any ideas? Or is my Omega 2 dead on arrival?

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  • @Alex-Clark said in Omega 2 DOA or Power Issues:

    Powering the Omega 2 in this manner produces the same results as all the other methods I have tried, which includes a CR2032 (3.0v), two AAA batteries in series (3.0v), and the 3.3v rail from an Arduino Uno. The results are that the amber light lights up for about 20 seconds (this time I counted about 24 seconds in my head), and then it turns off. There is no Omega-XXXX ssid being broadcast that can be seen either by my laptop or my cell phone.

    I still retain the opinion that it sounds like a power-failure; when it tries to bring up the WiFi-interface and the SoC's power-usage spikes and your device turns off, when it's not getting enough juice. You really should try with a proper power-supply.



  • @WereCatf Even an ATX power supply can't handle the power-usage spike from this thing booting up?

    What would be a proper power supply? Is anything a proper power supply other than the Onion-branded power dock?



  • @Alex-Clark An ATX power-supply can be a quirky supply, like e.g. some of them require a 1A load on the 5V-rail in order to work right, even if you weren't using the 5V-rail for anything. I obviously cannot tell how your ATX-power handles things, but I wouldn't be surprised if it's a similar issue. As for how to power your device, you could use a linear voltage-regulator to drop down voltage from a USB-charger to 3.3V, or like I do, use a small step-down switching power-supply to drop voltage from a USB-port to 3.3V. The important thing is that the power is as close to 3.3V as possible and can handle ~250mA spikes.



  • @WereCatf That's interesting. I don't think I have anything like what you describe on hand, so looks like I'll have to order something. I'll have to wait longer to play with this thing, but on the plus side I'm learning a lot of interesting stuff, especially thanks to you. Thanks again for being so informative and patient.



  • I'm waiting on a better 3.3v supply in the mail now, but I took one of @WereCatf's suggestions of draining a 3.7v lion battery a little. I soldered leads to its terminals and ran a little motor off of it for a while, checking the voltage periodically.After I got it down into the input voltage range I was able to run it off battery, set it up, etc.

    Now if I can just figure out how to mark this as resolved...



  • @Alex-Clark I'm not sure that what was meant by "drain the battery" was to actually empty the energy of the battery until it reaches 3.3V. What you can do is put enough little resistances in series (or easier using a potentiometer) so the voltage drops to near 3.3V. Going from 3.7V to 3.3V will not make the resistance very hot.



  • @fossette A passive resistor is in no way a better solution, it's still the wrong way of going about it. It was simply to confirm that OP's problem was a power-supply issue, which it was, and it's now solved. The proper way of doing it would still be a linear voltage-regulator or a small SMPS, and he did mention he is looking into a proper power-supply now.



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