Hungry for Pins, RAM?

Any other STM32 based boards
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Slammer
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Location: Athens, Greece

Re: Hungry for Pins, RAM?

Post by Slammer » Thu Apr 28, 2016 10:51 am

STM8 price is sub 0.50$, for devices with A/D, and specs similar to ATMega8-16
You will find STM8 anywhere, specially in low-cost chinese systems. No wonder for hot sales.....

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martinayotte
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Re: Hungry for Pins, RAM?

Post by martinayotte » Thu Apr 28, 2016 2:01 pm

RogerClark wrote:I also googled LoRa and it was rather vague.
Although I didn't play with LoRa yet, there is plenty of manufacturers that provide such module.
The main advantage of LoRa is the "Long Distance RF".

http://www.microchip.com/wwwproducts/en/RN2903
http://www.semtech.com/wireless-rf/rf-t ... ers/sx1276
http://www.hoperf.com/rf_transceiver/lora/RFM98W.html

stevech
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Re: Hungry for Pins, RAM?

Post by stevech » Thu Apr 28, 2016 4:57 pm

LoRa is "just" spread spectrum with very long codes plus very low data rates, like a 1Kbps or less. And heavy forward error correction coding (ratio of check bits to data bits = coding rate).
So LoRa allows a receiver to get a decent frame error rate (FER) after coding corrections... of say -130dBm instead of typical SCADA 900MHz FSK modes that struggle at -95dBm.
As ever, this is trading coding rates and slow data rates for range - where range means long with line of sight or shorter with buildings/trees in the path but much longer than higher speed FSK.

What is interesting is that in the EU, and less so in the US so far, people are putting up LoRa "cell" sites in cities and backhauling these to form a WAN, using 2.4 or 5GHz for backhaul and 902-928MHz ISM band for LoRa access. Putting these cigar box sized things wherever easements and power permit. Mostly in 400MHz area, or 868/900MHz (for better building penetration than 2.4GHz). This bypasses the cellular operators' telemetry data pricing of about $5/month for SCADA, HVAC monitoring, home toys like IoT, and so on. I wonder if this self-funded thing will catch on in the US. Not much need for LoRa unless you live on acres of land. Or have commercial intents. The few LoRa gateways on the market are rather expensive for hobbyists; one can make a box for $50 or so. Power and fire code issues are ever-present challenges.

The Radiohead protocol guys are using the low cost LoRa modules for something. I did a lot of work with Radiohead a couple of years ago. Freeware. Excellent example of prudent use of C++ inheritance applied to small microprocessors. And exemplary use of Doxygen! That work is light years away from Arduino's kludging. http://www.airspayce.com/mikem/arduino/RadioHead/

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RogerClark
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Re: Hungry for Pins, RAM?

Post by RogerClark » Thu Apr 28, 2016 9:28 pm

What is interesting is that in the EU, and less so in the US so far, people are putting up LoRa "cell" sites in cities and backhauling these to form a WAN, using 2.4 or 5GHz for backhaul and 902-928MHz ISM band for LoRa access

I wonder how long it will be , before authorities, decide that this is illegal, as it makes it hard for them to monitor the traffic.

stevech
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Re: Hungry for Pins, RAM?

Post by stevech » Fri Apr 29, 2016 5:52 am

RogerClark wrote:
What is interesting is that in the EU, and less so in the US so far, people are putting up LoRa "cell" sites in cities and backhauling these to form a WAN, using 2.4 or 5GHz for backhaul and 902-928MHz ISM band for LoRa access

I wonder how long it will be , before authorities, decide that this is illegal, as it makes it hard for them to monitor the traffic.
In the US... never. FCC doesn't monitor unlicensed bands (e.g., ISM 430MHz, 902-928MHz, 2.4GHz Wifi/Ham band, 5.4/5.8GHz ISM) except when there is a serious complaint about intentional interference or radiating outside the band edges. NSA and local law enforcement, well, politics aside, 99.99% of these people are doing us all a good service, IMO.

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