Hi, I have a bunch of nRF24L01 Nodes in our IoT setup and all is working fine. But, we live out in the boonies within 50 miles of three power generation stations in three different directions.
Despite what the power company says, we get outages that last about 2-seconds several times a week and I believe they are power-distribution switching related. So, they came out and checked everything here and decide I must be imagining it. {sigh}
I know we do get the short breaks as the UPS on both desktop computers and two 3D printers all give a squeak for a few seconds then go quiet. Two different wiring circuits so it ain't the house.
Anyway, right after a 2-second break, sometimes, one or more of the Arduino-Nano Nodes lose contact with the base and I have to go manually reboot and all is good again.
I do not want to go to the trouble of batteries and chargers as the Nodes all come up OK after a full outage of 30+seconds or more. So, I am wondering if I can just add a Super-Cap to the supply that would hold the Nanos up for 10 or so seconds.
How would I do that? I am OK with soldering etc, just no idea on design.
If you live in the US or Canada, call the power company - your line supply should not be cutting out like that. Supercaps will certainly protect a circuit against a 2 second shut down, but depending on the circumstances, I would worry about spikes from whatever fault is causing them.
ChrisTenone:
If you live in the US or Canada, call the power company
Thanks Chris, as I mentioned above, I did that and they came out and they said, they found nothing in their stuff. All my neighbors get the same things, so it is the power company but I am guessing it costs a lot to fix so they are going with the "there is nothing wrong' ambit until someone sues.
I'd much rather just put in some super-caps than waste time on those greedy idiots. What value is the diode? Zener? Where does the free end connect +V or -V? Just a solderer I be.
SalineSolution:
Thanks Chris, as I mentioned above, I did that and they came out and they said, they found nothing in their stuff. All my neighbors get the same things, so it is the power company but I am guessing it costs a lot to fix so they are going with the "there is nothing wrong' ambit until someone sues.
I'd much rather just put in some super-caps than waste time on those greedy idiots. What value is the diode? Zener? Where does the free end connect +V or -V? Just a solderer I be.
The little curly-cues on the ends of the bar indicate that it is a Schottky diode. That's like a regular diode, but with a lower voltage drop. Your 5 volt (or whatever) power supply goes into the diode, and the VCC goes into your circuit. Depending on the current draw, it should last a couple seconds. Bear in mind that the voltage out of a supercap starts to decrease as soon as it starts. Also be sure not to over-volt the capacitor, even by a little bit. I particularly like the 5.5 volt Vishay caps, like this 1 farad one:
There are some nice supercaps coming on the market now. They used to be rather limited, particularly in voltage, but newer ones put several caps in series inside a package to increase the voltage.
If you put your own series circuit together you must "balance" them. That can be just a simple resistor in parallel with each supercapacitor.
The main issue to overcome is the inrush current at startup. The supercap will take an almost infinite amount of current when power is first switched on. I've been working on this for a while and there are several solutions I've found. I'm not at my computer now; I'll post a circuit recommendation later.
I suppose you pay for power?
Then you shouldn't accept brownouts like that.
If the neighbours also have that problem, then you have a strong point.
The power company should install monitoring equipment in your house.
Or maybe you could make a brown-out logger yourself with an Arduino (and one or two for the neighbours).
A Wemos D1 mini could log many events with timestamps on it's internal SPIFFS memory.
Use a cellphone powerbank as UPS.
My Wemos keeps on running for 36hours on a small 5Ah powerbank after it's mains power cuts out.
Leo..
ChrisTenone:
The little curly-cues on the ends of the bar indicate that it is a Schottky diode. That's like a regular diode, but with a lower voltage drop.
I have some 1.5F and 4F, 5.5v caps I bought some time back on special somewhere. The name looks to be "cdo" and thought I might have a use for them some time.
MorganS:
I'll post a circuit recommendation later.
Thanks, but don't go to trouble on my account. I'll give the caps a try.
I am mainly bitching today as the Node that did not start correctly today is outside in the well-head. It's ten minutes work getting in and out of it. Most of the other Nodes are all easy access.
Also, quite often when they almost restart after the blip, the radio is often still active and I can trigger a reboot I have built into each Node. Today the radio did not come back up. So out to the well head in the freezing cold.
I would also have a serious chat with your state regulators - you are at risk of voltage spikes that can damage your equipment - some years ago the power company was doing work on the lines and put some trees into the lines - some power surges got past my protectors and fried the motherboard on my computer - was an expensive fix - I would think your other electrical appliances would be at risk -
We live 5-10 mikes from two dams producing the electric power we use. The Bonneville Power Administration, a government agency, moves the electric power generated at the dams to a central distribution substation where your local power company buys the power to sell to you.
Your power company is correct, it is not their equipment. It is the BPA doing it. We have the same problem with short. tiny, power interruptions. Just a few cycles, usually. Try to complain to a government agency.
To complicate the system even more, the dams and dynamos in the dams are owned and operated by Portland General Electric Company.
That way, no one can be held accountable for yours and my power glitches!
Paul_KD7HB:
Try to complain to a government agency.
Thanks Paul, way too hard, we will just continue to live with them. Hopefully the Super-caps will solve the problem, or at least have enough capacity to work most of the time.
If not, I may just do the battery and charger thing on the well-Node. The rest of the Nodes are just an annoyance, but fairly easy to get to the reset button.
