DriveWay entry monitor array

[defragster]

A variation of SensorNet, I want to purchase and modify some solar charging PIR activated motion lights.  I have seen (on ebay not tested $15-30) some now shipped with an 18650 LiPo that have a built in solar recharge system.  The 18650 is a 3.7v battery with decent reserve power that could enable periodic activation between low power sleep.  With good sun recharging they may self sustain.

These units wired with a PIR might be hacked to detect any motion (typically they don't turn on lights when charging i.e. daylight) and if that could wake the OAK/ACORN it could report to the network the detected motion.  Even from a cold boot the OAK is seen to be network ready in 6 seconds - perhaps faster from a sleep state or transmit off receive only state if possible.

Problems: Some have metal shells that would inhibit radio signals getting very far up my 500ft driveways.  Also they may have limited room inside for adding hardware.  And adding an active load on the LiPo may confuse the required control of the detection system that is needed to safely charge LiPo cells.  Others use 3 AA NiMh cells that could provide similar reserve.  One factor in this is the included solar panel - the $30 unit with 18650 seems to have a larger recharge output which could be important to no maintenance usage.  Adding this might take an external wired housing to hold the OAK (and perhaps even a way to switch between a running cell and a charging cell)?

I'll look to buy one or more of the PIR/SOLAR lights and maybe start with a PRO nRF24 solution until the OAK KS hardware is made ready.  Any tips on similar experience are welcome.

[defragster]

Erik: On KS you once posted the range you were seeing on these?  Was it 150ft?  It must have been a comment and older posts not paging in for me.

I walked my driveways and 180 feet was the common mounting and clearest line of sight points - except of course an evergreen tree branch may come in at the last - and those hold lots of water some months here. And the two drives are about that far apart - with higher tree count between.  Maybe I can find a sweet spot - but no sun there.

OAKs don't do MESH networking - it there an easy way to transmit data point to point up the chain?  Manual IP chatter?

[Solice]

I was thinking about this when I read your project.  I recall Erik saying that the Oaks can operate in access point mode.  Perhaps there's a way to leverage this by having an Oak AP (maybe two Oaks, to create an Oak router) to cut the effective total distance between links?

EDIT:
On second thought, that would require you to keep at least one of the Oaks in the Oak router powered up.  I'm not sure what the power budget is for this, but it would probably eat right through it like that... Pringles cans?

[defragster]

We'll have to see where that goes - on one end I have power at a couple points - but it is the middle where the AP would be needed - with no power and no sun.  I'll have to find a decent battery exchange system - or make the units interchangeable and swap them out as needed.

One other thing I saw was - creating a MESH with NRf24 devices to connect?  Perhaps those would be lower power with Pro's or something?  But unless they gain range and use much less power it would be adding another layer and it seems one OAK would end up like your post and need to have an OAK with both radios active for routing.

[dougal]

If you have line-of-sight (more or less), you might consider a cantenna to extend your range directionally.

[defragster]

Will have to see - but I'd need that on both ends - or is the cantenna that receptive from distance as well?

[dougal]

I'm not positive, but I'm *pretty* sure that you can probably just use it on one end. Also the "line-of-sight" might not have to be *completely* clear. A few tree branches and such might not be a big problem? Seems worth a try!

[jamieisboss]

https://en.wikipedia.org/wiki/6LoWPAN seems to be pretty much designed for this, there doesn't appear to be a reason why the hardware couldn't to it, it'd be a case of adding to the firmware but how much I dont know, if the boards are ipv6 ready then maybe not as much work as it sounds?

On the other hand presumably you've got a wireless AP outdoors that the Oaks will be talking to if you've got a 500t driveway, could you not just buy a high gain antenna/antennae for that, not sure what the laws are or where you are but I can't imagine you'd get in trouble/anyone would notice if you were only covering your own property. If the Driveway is relatively straight, you could even add a dish to make it more directional

[PeterF]

One other thing I saw was - creating a MESH with NRf24 devices to connect?  Perhaps those would be lower power with Pro's or something?  But unless they gain range and use much less power it would be adding another layer and it seems one OAK would end up like your post and need to have an OAK with both radios active for routing.

I don't know if you're still thinking about this, but I'd be strongly considering the nrf24 route for all the nodes bar the last, and do an oak with nRF for that if you want to end at a wifi connection / web page. you can get nRFs with external antenna which will do a decent range, and then go for ones with Power Amps if you really need a power boost... but are a bit power hungry when going to those extremes. Normal nRFs with external antenna in mesh mode would probably do the job you need.

Pete

[defragster]

I just saw that Adafruit is making a breakout version of this device (low data rate) HopeRF RFM95W 915Mhz [Long range: 15 - 20 km.] - LoRaTM Ultra Long Range Wireless Transceiver: http://www.ebay.com/itm/181442612615

AdaFruit breakout is $30 - the raw radio is $10: https://www.adafruit.com/products/3072

It is SPI - not sure if driver code will work for OAK - for remote places it could be tied to a Teensy or other.

http://www.radio-electronics.com/info/wireless/lora/basics-tutorial.php