The WORKBENCH part 2


(LoRaTracker) #128

LoRa CAD.

I did some checking to see how effective CAD was at detecting SF12 packets, you might be interested in the results.

The CAD process detects the preamble and the body of the packet. There is around a 5dBm loss in sensitivity, i.e. it wont detect the weakest packets.

There is a gap in the CAD detect at around the point the pre-amble ends. Its possible CAD picks up the pre-amble and the body of the packet, but not when there is bits of both during the detect window.

Full details here;

http://www.loratracker.uk/?p=884


#129

interesting experiment … and indeed that 'gap is a bit strange.
I was thinking about a graphical equilizer like led display, representing the channels and the signalstrength :wink:


(LoRaTracker) #130

Indeed the gap is odd.

The consequence would be that if a CAD was detetected, and you waited for it to fail dont assume a clear channel, it could be the gap.


#131

stuck in the LoRa twilight zone :rofl:


#132

Thanks Felix,

Nice improvement for uCurrentGold,

Awesome, got $120 less on my bank account, and I guess @BoRRoZ also soon :wink:


#133

need one :rofl:


#134

image


#135

you happy with it Charles ?


#136

I’ve got old version and LowPower switching from sleep uA to wake mA was really a pain, this one will solve this this issue :wink:
Waiting for it, and got an uCurrentGold to sell :wink:


#138

waterproof

:stuck_out_tongue_winking_eye:


#139

x1082

while the ‘official’ charger is under construction, I use a bench power supply


#140

expensivemail

something I noticed lately … why is shipping to NL getting more and more expensive ?


(Jeff Uk) #141

Same in UK I’m afraid…tied to recent increases in Oil price hence petrol diesel shipping oil & aviation fuel all heading north!? :frowning:


#142

yes maybe… I think there are some ’ postal problems’ between countries behind the scenes… we’ve seen that before.


#143

tested various buck/boost modules (for a mobile powerhungry device)

x1084

and we have a winner :thinking:


#144

It’s too good to be true .:grin:… I paid a little more but I have a nice device on my desk and made some handy adapters for my lipos.

Opus


#145

charge1

:stuck_out_tongue_winking_eye:

got my money back 5 minutes after I complained to eBay … so no problem.

charge2

the used lipo business is booming


(Amedee) #146

What ‘s the purpose of all this?

Sorting to match capacity?


#147

There is a trend at the moment (mostly US / AU) that people are interested in storing energy (search FB groups) coming from their solar panels / windmills.

diywall

But also in certain area’s… where people know they are out of electricty when a hurricane strikes.
There you see these kind of ‘energy suitcases’ … professional but also DIY
Filled with battery’s and an inverter, sometimes solar chargeable too.

tksifs0

lightcase

Problem is that you need a lot of battery’s (and know what you’re doing!)
If you can afford it you buy a used TESLA battery pack (U$1400)
Tesla-battery-pack

or a bunch of new NCR 18650’s … but many DIY are using recycled (but still good and capacity tested) battery’s for 1/4 of the new price.

For example, battery packs from electric handtools… if the battery doesn’t work they end up at a dumpster somewhere.
If you open them in many cases there’s only one bad cell… the same is to say for laptop battery packs.

So what they do is sort them on capacity.
First discharge them completely and then charge them… let them rest for a month and measure the self discharge…
bulkdischarge
Then some rewrap them in a new plastic and use/sell them.

If you create a battery pack with these used cells you make sure you match the capacity because you connect a few paralell (with a battery management system or BMS)

pack1

building these packs is a form of art :sunglasses:
also you see interesting developments… like stackable 3d printed battery ‘drawers’.
lipodrawer1

lipodrawer2

just some more pics (yes I’m interested :sunglasses:)

minicase

setup

table

casefull

So where comes the LoRaWAN ?
Well… what they do is monitor each cell (barium) and good systems shut down a pack when there’s something wrong.
My idea is to try todo that over LoRaWAN … so wireless monitoring of powerwalls / energy backup suitcases.

russian LiPo test LAB


#148

x1086
RJ45 connectors from the patch cables are to long, can’t put the lid on the enclosure. :unamused:
I ordered Right Angled 90 degree patch cables.

x1087
ruggedising interior (battery compartment) enclosure