2 questions about the new Particle Mesh devices

I’m considering pre-ordering some particle mesh devices (1 Argon and 2 Xenon devices), and I just have a couple of questions:

  1. How would I provide power to these devices? Can I power them using batteries? If so, where can I buy them, and approximately how much do they cost? Also – do I need to buy any additional hardware to be able to power the devices using batteries? And what kind of battery life can I expect based on the type of battery that’s recommended?

  2. Can these particle mesh devices be used as WIFI repeaters at all? If so, what kind of bandwith and/or reliability should I expect? And is there a limit as to how far out I can expand the mesh network until the performance degrades to a point on unusability?

Thanks,

  • Yvan
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How would I provide power to these devices? Can I power them using batteries? If so, where can I buy them, and approximately how much do they cost? Also – do I need to buy any additional hardware to be able to power the devices using batteries? And what kind of battery life can I expect based on the type of battery that’s recommended?

Yes, you can power the devices by batteries. However, gateway and repeaters have to be on all the time, so it’s only practical to power them by USB power adapters, computers, etc…

All of the devices have a JST-PH battery connector for a 3.7V LiPo battery, same as the Electron. Only the Boron 2G/3G includes a battery, however. All others you will have to purchase one separately.

All of the 3.7V LiPo batteries at Adafruit are compatible, and are available in sizes up to 6600 mAh.

There is a charger built into the devices that will charge the battery when powered by USB.

It’s too early to say the exact battery life, and it really depends on a lot of factors. Using a Xenon that only wakes up for a second every 15 minutes would probably run for months. An Argon running full speed, maybe a day or two, using a 1800 mAh battery.

Can these particle mesh devices be used as WIFI repeaters at all? If so, what kind of bandwith and/or reliability should I expect? And is there a limit as to how far out I can expand the mesh network until the performance degrades to a point on unusability?

No, they cannot be used as a Wi-Fi repeater. And the mesh network is low-bandwidth. You should only expect to get the low 10s of Kbytes per second. It’s not intended for high-bandwidth usage. The exact numbers have not been determined and will vary depending on the number of hops in the mesh as well.

Rick

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Thanks for your reply Rick. That’s a shame that these devices can’t be used as WIFI repeaters. I had a big million dollar idea, and now it’s shot. Oh well.

Regarding the batteries – is there a more cost effective option besides LiPo batteries (they seem rather costly)? I remember there being some discussion about using coin/watch batteries as a power source (for low power usage situations, presumably). Was I mistaken about this, and Is that simply not an option with these devices?

Thanks,
– Yvan

Anyone?

The possibilities for batteries are endless. But you have to have a use-case or some type of desired runtime between charges/replacements to determine what batteries you can use. For super low power applications, consider the 15uA quiescent current for the mesh voltage regulators as discussed in this post. I haven’t seen specs on nominal current while awake yet but the promise is that the mesh devices will have a fairly low power consumption compared to the Electron and Photon.

For extremely low power applications there a couple solder pads on the Xenon. One (normally closed) connects 3V3 to the output of the regulator. You can cut that one and close the one that connects VBAT to 3V3.

Then you can instead put your coin cell power directly into VBAT without a regulator. The nRF52840 has a wide supply voltage of 1.7V to 5.5V, though other parts have a smaller range (like the external SPI flash, 2.3V to 3.6V recommended).

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Thanks guys. I was hoping there would be a simpler way to connect the smaller and more cost effective batteries to these devices (without having to do any soldering) … but it appears that this isn’t possible. Regardless, I’m curious to see what kind of innovation occurs once these devices are finally out in the wild.

– Yvan

The Xenon has some limitations imposed by the Adafruit feather form-factor. The X series SoM (system-on-a-module) does not. The SoM does not contain a voltage regulator and breaks out the various supplies in separate pins so you can easily implement things like coin cell power.

Of course you do need to build your own board with the M.2 connector to plug the SoM into but you don’t have to manually rework a lot of Xenon modules, which would of course be impractical at scale.

Hi Rick,
So if you are building boards that have an external power supply of 5V would you use the method above? Or would it be preferable to add a USB cable from said board to the Boron? I am used to having the VIN on my electrons so trying to figure out how I am going to keep this sucker charged. :slight_smile:

I would prefer to have it wired on the board to a pin on the boron rather than have another cable.

Thank you in advance.

Charging or using the device with a 5V external supply is a different matter.

I’m pretty certain from reading the schematic and trying it that you can supply 5V to the VUSB pin to power and charge the mesh devices. There is one really important caveat, however: There is no Schottky diode like there is on VIN on the Photon and Electron so you should never both power by VUSB and the actual USB connector at the same time.

Thanks Rick,
Note to self, remember to flip the kill switch before plugging the unit into the computer. :joy:. I wonder how many of these I am going to fry before I remember that.

@RWB See above about charging the new devises.

If you are putting them on a custom PCB just make sure to add a protection diode to - at least - protect your own PSU :wink: Nevermind the USB port :sunglasses:

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Thank you.
I had to add one on my electron PCB. I found if I plugged the usb into the unit while connected to the board, the screen on my flow meter would light up. oops.

I was more concerned on the new units that if you had power to both the VUSB from external power supply and plugged the Boron into the computer via USB you would fry the Boron. Is this incorrect? Is the concern more for frying the external power supply?

You won’t damage the Boron, but you could damage either your regulator or your computer USB port, depending on how much they dislike being fed voltage.

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Makes perfect sense. Glad we discussed it.

Thanks again for your time answering all my questions @rickkas7 and @ScruffR

I appreciate the detailed support.

Cheers,
Tom

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Does the yellow light to the left of the usb port glow solid when charging? See photo.

Yes it should. Why?

From the docs:

https://docs.particle.io/datasheets/wi-fi/argon-datasheet/#charge-status-led

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Because if it didn’t mean charging, but instead meant something like the Argon was about to burn up, then I would have unplugged the USB. Glad to know it means charging and even more happy that I can charge the battery with the USB.