https://github.com/mignon-p/esp-opc-server

Open Pixel Control server for ESP8266
https://github.com/mignon-p/esp-opc-server

adafruit-feather-huzzah esp8266 neopixels open-pixel-control

Last synced: about 1 month ago
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Open Pixel Control server for ESP8266

• Host: GitHub
• URL: https://github.com/mignon-p/esp-opc-server
• Owner: mignon-p
• License: bsd-3-clause
• Created: 2017-01-25T17:54:23.000Z (almost 8 years ago)
• Default Branch: master
• Last Pushed: 2019-12-04T21:28:09.000Z (about 5 years ago)
• Last Synced: 2024-09-06T11:07:21.819Z (4 months ago)
• Topics: adafruit-feather-huzzah, esp8266, neopixels, open-pixel-control
• Language: C++
• Homepage:
• Size: 319 KB
• Stars: 15
• Watchers: 4
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

        
This is an [Arduino][1] sketch which implements an

[Open Pixel Control][2] server for controlling [NeoPixels][3] from an

[ESP8266][5], such as the [Adafruit Feather HUZZAH][4].

Here is an example circuit:



Bill of materials:

* [Adafruit Feather HUZZAH ESP8266][4]

* [74AHCT125 - Quad Level-Shifter][6]

* [470 ohm resistor][7]

* [Big Freaking Capacitor - 4700uF][8]

* [NeoPixel stick][9]

You will need to edit the sketch to set the number of pixels you have,

and your WiFi SSID and password.

Once the sketch is running, you'll need to figure out which IP address

it has been assigned.  Generally, your router's web interface will

have a way to look at DHCP leases, and you can find it from there.

It may also be useful to call [WiFi.hostname()][13] to assign a

hostname to your ESP board.  This may show up as `hostname.lan` in

your DNS, although it [depends on your router][14].

Once you know the IP address or hostname, you can connect with any

Open Pixel Control client.  The [openpixelcontrol repository][10] has

some [clients in Python][11], and I have [a client in Haskell][12].

## Caveats

This example is a nice proof-of-concept, but there are a couple of

reasons it isn't a robust solution.

First, interrupts are disabled while writing to NeoPixels.  Interrupts

are necessary for WiFi to work, so the server may eventually crash and

need to be rebooted, especially if you have a lot of NeoPixels.  (This

problem could be alleviated by using [DotStars][15] instead of

NeoPixels, because DotStars are not timing-sensitive and do not need

to disable interrupts.)

Second, Open Pixel Control runs over TCP, and

[TCP is not the best for real-time applications][16].  If a packet is

lost, TCP will retransmit it, delaying the packets after it.

[UDP][17] would be more suitable for this application.

[1]: https://www.arduino.cc/

[2]: http://openpixelcontrol.org/

[3]: https://www.adafruit.com/category/168

[4]: https://www.adafruit.com/products/2821

[5]: https://github.com/esp8266/Arduino

[6]: https://www.adafruit.com/products/1787

[7]: https://www.adafruit.com/products/2781

[8]: https://www.adafruit.com/products/1589

[9]: https://www.adafruit.com/products/1426

[10]: https://github.com/zestyping/openpixelcontrol/

[11]: https://github.com/zestyping/openpixelcontrol/tree/master/python

[12]: https://github.com/ppelleti/hs-opc-client

[13]: https://arduino-esp8266.readthedocs.io/en/latest/esp8266wifi/station-class.html#hostname

[14]: https://unix.stackexchange.com/questions/92441/whats-the-difference-between-local-home-and-lan

[15]: https://www.adafruit.com/category/885

[16]: https://en.wikipedia.org/wiki/Transmission_Control_Protocol#Alternatives

[17]: https://en.wikipedia.org/wiki/User_Datagram_Protocol