Electronics for the JavaScript Developer Using Wi-Fi and Bluetooth LE
dev.opera.comThat sure was Very Pedagogical, with large pictures of components and wires. Nice!
Nitpick: it says that "capacitors are polarized", which is not true in general. There are many kinds of capacitor, some of which are polarized. The electrolyte capacitor in the image is polarized, but I feel there could be a bit more precision in the wording.
Thanks for spotting my mistake. I have amended it in the article.
Definitely not nitpicking when it's a fact :)
I think one should consider COAP or MQTT over HTTP protocol on low energy devices. May be author is using HTTP because it's simple to start with.
I like spark wifi module. But, I feel it's quiet costly (Photon $19) for some countries (Example: In India it's almost 1200Rs). Mount it on every IoT device will not be cost effective. May be that is one of the reasons, everybody is excited about it but very few are buying/using it.
Now a days, I am working with ESP8266(around $5) wifi module and found it very interesting. It is quiet new, but programming is pain on it.
Edit: ESP8266 price update
i think there's arduino support for the esp:
http://makezine.com/2015/04/03/esp8266-community-added-ardui...
I'd love to try Spark - Photon seems to be out of stock at the moment though.
In the last couple of weeks I've been dabbling with Arduino Uno and Nano and have been very impressed by how plug-and-play everything is.
But I've been super-impressed with the ESP8266. A thumbnail-sized wonder which has a 32-bit CPU, GPIO pins, wi-fi, more RAM than the usual Atmels, costs peanuts ($5) and is available worldwide on ebay and other sources. Now that it has both the Arduino IDE and the nodemcu Lua environment, this little thing is poised to take off. I just finished wiring up a temp sensor to the 8266 using the Arduino IDE. Now I have a tiny temperature web-service on my wi-fi network, responding to a Bonjour/mdns name and it took all of half an hour.
Everyone understands HTTP and it interoperates with all your existing systems. To do COAP or MQTT requires sorting out a suitable backend.
The big IOT unsolved problem is more to do with security and updates.
ESP8266 is amazing, but I think it's problem is that it doesn't have CE certification, which will make it harder to sell devices with it on-board.
But it does -> http://www.seeedstudio.com/depot/ESP8266-based-WiFi-module-F... :)
You're right, but apparently there are caveats:
http://hackaday.com/2014/12/17/esp-gets-fcc-and-ce/
"This announcement does come with a few caveats: the chipset is certified, not the module. Each version of the module must be certified by itself, and there are versions that will never be certified by the FCC. Right now, we’re looking at the ESP8266-06, -07, -08, and -12 modules – the ones with a metal shield – as being the only ones that could potentially pass an FCC cert."
You can get the esp8266 modules for around $2.43 now from Aliexpress
Talking of Hardware and Javascript I have to plug the Espruino: http://www.espruino.com/Reference
Disclaimer: My pico arrived the other week.