SPI Port Expansion using MCP23S17 DEMO

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Re: SPI Port Expansion using MCP23S17 DEMO

By forlotto
- Sat Sep 03, 2016 5:11 pm #54406 Electrogaurd I think you are looking for something more like this maybe?

http://www.hobbytronics.co.uk/adc-i2c-slave

ADC's to get analog readings from devices possibly.

Or are you looking for something to use that has better interrupt features to preform a task if a button is pressed hard to understand specifically from your question just what it is you want without knowing what you are trying to do I guess.
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Re: SPI Port Expansion using MCP23S17 DEMO

By Electroguard
- Sun Sep 04, 2016 6:21 pm #54474 Thanks forlotto, but I think I've already got things covered ok.
And I doubt anyone could have guessed my intentions just from those questions... it's for an automation and control system - and if that seems a bit vague, it's because the system is intended to be versatile and pretty much whatever may be needed.

I've been down a similar road in the past, but with arduino, until eventually running out of arduino resources just when things were starting to get useful.

So now, rather than trying to squeeze everything onto any single device, my intention is to create similar equivalent system functionality but distributed across a cluster of interacting ESP_Basic udp wifi nodes. In theory this should allow almost any new functionality to be added whenever needed.

It's all still only proofs of concept (as is ESP_Basic itself according to the disclaimer), but I've successfully achieved working hardware for a Relay node, PIR sensor node, Voice Announcer node, Infra-red TX/RX extender pair, and an IR voice menu with IR button cloning... which already offers most of the required system functionality.

My questions were due to the fact that I still need to do a multi-sensor Triggers node (port expander inputs), a CCTV camera switcher (port expander outputs), and a CCTV PTZ joystick controller (multiple ADC channels), plus other stuff.

I've already got some PCF8591 i2c 4-channel A2D modules (they even come with LDR and thermistor), so I'll probably use one of those for the joystick controller, and another to monitor PSU voltage and light levels etc.
http://www.ebay.co.uk/itm/1pcs-PCF8591-AD-DA-Converter-Module-Analog-To-Digital-Conversion-Arduino-Cable-/191840415195?hash=item2caa946ddb:g:cJEAAOSw6wRW~6-Q

I've also got some 8 bit cascadable i2c PCF8574 modules
http://www.ebay.co.uk/itm/PCF8574-PCF8574T-Module-Communication-Module-I-O-Expansion-Modules-I2C-W-/262382854591?hash=item3d173ca1bf:g:GBwAAOSwsN9XDJ9t

and a bunch of 16 bit i2c MCP23017 port expander chips, plus I've ordered some spi MCP 23S17 versions ... so I'll be able to 'suck it and see' whatever's going to be the most suitable. I don't have a problem with mixing spi nodes for some things and i2c nodes for others, rather than trying to squeeze everything on to 1 device (I've already got that T-shirt).

The multi-input Triggers node is perhaps the single most important system item because it will be hard-wired to the beam-break sensors, PIRs, and magnetic door contacts etc, and needs to be responsive and reliable, plus electrically bullet-proof (a combination of PTC fuses and opto-isolators should deal with that).
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Re: SPI Port Expansion using MCP23S17 DEMO

By forlotto
- Sun Sep 04, 2016 9:53 pm #54485 Wow sounds excellent man !

Where did you pick up your breakbeam sensors?
I'd like to get a few for my project but specifications are rather odd on these things I read something like 10" at 5v.
I need a break beam at least as wide as a door way.
Unless the 10" is referring to the width of the beam.
errr IDK would be handy though to have some break beams in my doorways.
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Re: SPI Port Expansion using MCP23S17 DEMO

By Electroguard
- Mon Sep 05, 2016 5:19 am #54507 Most of my stuff has come from ebay, mainly because ebay gives buyer protection to prevent seller rip-offs.

There's a bit of a trick I've learned for finding the best ebay deals.
I'm an ex-pat Brit living in France, so I would use ebay.co.uk, but the trick is to change the left-hand 'Item Location' from 'Default' to 'Worldwide', so then you will get shown similar listings from the same asian suppliers but posted also on the likes of the Aussie and USA ebays etc, which often offer better prices on the same items because of fluctuating exchange rates and global language misunderstandings.
It doesn't matter to the same asian supplier whether he sends his foreign better-priced listing found on another countries ebay directly to your country instead - he makes a sale that he may not have done otherwise, and you pay less for the same item than you would have if bought from your local ebay. That is assuming that the wanted item was even available on your local ebay, often it might only be available from a different country.

I also change 'Format' from 'All listings' to 'Buy it now' to get rid of all the haggling rubbish.

And I would always click 'Free P&P' in 'Delivery options' when lookinfg for the cheaper stuff...if you can't find what you want with free delivery, you can always unclick it and see what's on offer with paid delivery.

Some pointers about Beam-break sensors...
Some short-range types just bounce an infra-red LED back from a remote reflector and look for the reflection to be interrupted. Others have TX and RX units, but it's still just a simple led beam. Possibly battery driven. Range is typically just a few feet.
Do a 'Worldwide, Buy-it-now, Free-delivery' ebay search for "infra beam sensor" to see what's available.

Better security type beam-breaks will typically use a 12v supply, dual beams, probably through optical lenses, and using coded pulses to improve reliability and range and minimise false triggering from falling leaves etc. Range is typically 10 to 100 metres.
Do the same search as above, but without Free-delivery, to see what else is available.
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