So, just thinking how coverage could be expanded out west here where there are large swaths of open area with limited coverage at lower altitudes.
How much power would it take to run a Pi with Piaware, and a cellular modem to send back the data? I’m thinking a solar panel and battery large enough to run the Pi 24x7 assuming nearly every day is sunny (AZ desert). Put the thing in a weatherproof container and put on top of a mountain for best reception - range should be incredible.
I looked into this a few months ago and this would be doable with a sufficiently large solar panel, but I think you’d have to cobble something together yourself since the “solar/battery USB chargers” on the market are not sufficient for 24/7 operations.
What kind of site are you talking about and what is your access to it? Or are you thinking just build the thing for a couple hundred bucks and leave it on a mountainside? That would probably work for a long time although you’d need to make sure your scripts could reliably restart and reconnect the cell connection.
I’m thinking “build it and put it on the mountainside”, security would be via making it blend in and having it in a remote area not frequented by people… No question I’d have to cobble it together myself… What kind of datarate does a busy PiAware need?
If it’s on a mountainside in the US, it would definitely get some unique coverage but probably not be busy compared to the urban installations, particularly in Europe. Probably a few hundred megs a month? If it was running MLAT, it might be a few times more.
I’m sure someone here has the tech to determine the exact power requirements and knows more about solar/battery rigs than me.
Documenting this process well with links, pics, videos, etc, could allow a large number of people to do similar setups.
If I attempt it, I will document. Pretty much all jet traffic is covered well by existing stations, but for the piston folks, FlightAware’s ADS-B coverage is more limited at the altitudes we fly at in some areas.
I’m not sure what would be more reliable, plugging the USB modem into the Pi, or using something like this… It definitely ups the price of the entire setup, which is especially undesirable if leaving unattended on a mountain.
i looked in to doing the solar panel/rechargeable battery thing for this application, but solar panels are pretty expensive, and the size/cost is kind of prohibitive for this project, especially since you need to juice the battery long enough to last the night. if you’re in the states there is a wireless provider (the name is escaping me right now) that offers a 3g/4g usb stick with 200mb of of data free per month.
i was also concerned with wildlife interfering with the unit cascading into some wild event where the hillside would end up on fire.
A raspberry pi B+ has a power consumption of around 3W. The R820T2 receiver draws 350mA from the USB port, and I don’t know what a USB cellular data dongle draws, but a quick search suggests that a maximum of around 300mA is somewhere in the right area. It would probably be a good idea to use a powered USB hub, as my pi is unreliable with a wifi dongle and R820T2 connected. I don’t know if the hub itself will draw any power, but lets assume it uses 1W (probably an overestimate for a decent one). The total electrical power needed is about 7.25W from a 5V supply.
If we use a switching regulator to obtain the 5V supply from a 12V battery there will be some inefficiency, so a worst case power consumption from the battery is about 10W that we have to sustain 24 hours a day. If we assume 12 hours of sunlight, then you need a minimum average of 20W from a solar panel (to power the pi during the day and recover energy used over night). The solar panel will need a higher output than that, as unless you have some arrangement to make it track the sun, it won’t produce its maximum output all day, and there are inefficiencies in charging the battery.
I would estimate that a 40-60W solar panel and a 20Ah sealed lead acid battery would be sufficient to reliably run a set up like that with a bit of power in reserve. According to ebay, panels that power are about 900mm x 550mm and cost somewhere in the region of £100. You would also likely need some kind of charge regulator as without one the battery will be damaged.
It’s probably going to cost a few hundred £/$ to do this unless you can do the electronic bits yourself.
I may do this with WiFi just for Shiggles (that is a technical term K6RTM might use). Would be another way to get everything up to the antenna without running a cord. Home Depot, Lowes, Menards, Wally World, and even Meijer carry solar panels in my area. Outdoorsy stores carry Coleman “camping and RV” panels too. A lot of variety in size, efficiency, and price range. The appropriatly sized panel should be the most expensive part.
Everything is right about the power usage numbers but the implementation has some pitfalls if you are not careful.
The solar insolation values are probably the best way to rate the total power generation of the system. It can be a lot less than the 12 hours of sunlight that was mentioned because of clouds and angle of the sun. It is usually closer to 7-8 hours for Arizona. Sun tracking system bump the values up a couple hours but usually it is cheaper to get bigger panels. wholesalesolar.com/solar-inf … urs-us-map bigfrogmountain.com/SunHoursPerDay.html
A 30,000 mAH Li battery packs for recharging cellphones work great for a power source. They usually are the same price and capacity of a Lead-acid battery without the size and bulk. The only problem I found was that the a lot of packs would disconnect the RPi and wouldn’t turn it back on without a physically disconnecting and reconnecting the power cord. I also haven’t tested Li-ion packs for temperature so it might not work in a the hot Arizona summer.
The small lead-acid batteries (not car size but golf cart size) for $30-50 should work fine. The power regulators that were linked before works well with 12V lead-acid systems but you can also check if panels have built in regulators for 12V systems. Most camping panels have built in regulators.
Ultra capacitors and still too small a charge for running a remote PiAware but the tech is improving fast. Just another 5x improvement and we would see them a lot more devices. They are mostly a niche product but they have started to appear in more computer backup systems.
One last thing. We also have a software that work on android phones (flight feeder for android). Cellphones has built in 3g or 4g data and a battery for an hour of run time. An external battery pack and solar panel should get the system working over the entire night with cloudy conditions during the day.
A friend is running a fairly large wireless Wi-Fi network on solar. Has relay towers on terrain high points. Covers 10-15 miles out from his base. Has offered to host receiver on his tower(s) and tells me power is not a concern. But, we have to dig into filtering interference (1000 MHz) from another transmitter he runs on the same towers. Would be great if it works - no cell data charges.
That sounds like the way to go. Filtering is the easy part.
Harbor Fright (sic) solar panels? Very funny…
Anything you put up on a mountain has to be built to survive the apocalypse… Please remember also that things put up on towers on a mountain never fail in good weather.
One of the first things I’d want to figure out before putting a Pi-based system in a remote location (and I’m thinking of putting one at a friend’s house on the other side of the Valley) is a reliable way to remotely force a reset on the little sucker. Having it at someone’s house at least gives me the option of giving someone a phone call and telling them to push a button on the box.
Suddenly the whole android app makes a huge amount of sense! May bust out the Kill-A-Watt meter to do some comparisons between Pi, Phone, and tablet. Also have a BitScope that could come in handy with a shunt for measuring current in more detail.