Cinema Display LED control with 9V-12V ESP8266 Web Switch

I picked up one of the A 4 Cinematic Light Box devices to use as a team sign in an Agile Program Increment planning meeting.  The unit requires 6 AA batteries. That seemed wasteful so I added a 9V barrel jack to it to power it with a 9V wall wart.

The next step in turning a $15 box into a $40 project was to add an ESP8266 relay board to enable WiFi control for the sign light.  My controller is ESP8266 Link Sprite LinkNode R1 that was locally available at Microcenter for $11.


Basic Circuit.

The basic idea is to turn the ESP8266 into a 9V switch that needed no external power. I wanted to tap the 9V intended for the display LEDs and drop it to 5V to run the ESP8266 without need of a 2nd power source.


Two diodes tap power from either jack and sends it to the ESP8266 and relay circuits.  It doesn't matter which jack is used as the inbound power source and which as the outbound to the display. Either will work because of the two diodes. They are arranged a way that doesn't limit which direction current flows through the relay.

Fritzing didn't have any LinkNode devices. The relay and WeMos in the Fritzing diagram are actually on the same LinkNode board.

Parts


The whole circuit, regulator, control board , diodes and jack all fit within a Mentos tin.

I was worried about wifi reception but that isn't an issue with my target location.

The final design uses a UBEC switch mode DC regulator intended for R/C devices. That regulator accepts 5.5V to 26V inbound that it converts to 5V outbound. This means the device actually acts as a self powered in-line switch for any circuit 5.5V to 26V
  • ESP8266 board with relay
  • 2 panel mount barrel sockets.
  • 1 UBEC regulator
  • 1 Mentos tin
  • 2 Diodes

Input / Output

The two barrel jacks act as input and output ports. The ports are "joined" through the actions of the relay.  Either port can act as either input or output.

GitHub

Source code for this project can be found on GitHub: https://github.com/freemansoft/ESP8266/tree/master/Relay-OTA-demo




You wanted Video?

We got video!
 


Comments

Post a Comment

Popular posts from this blog

Installing the RNDIS driver on Windows 11 to use USB Raspberry Pi as network attached

Image
I do a lot of my development and configuration via ssh into my Raspberry Pi Zero over the RNDIS connection. Some models of the Raspberry PIs can be configured with  gadget drivers  that let the Raspberry pi emulate different devices when plugged into computers via USB. My favorite gadget  is the network profile that makes a Raspberry Pi look like an RNDIS-attached network device.  All types of network services travel over an RNDIS device without knowing it is a USB hardware connection. A Raspberry Pi shows up as a Remote NDIS (RNDIS) device when you plug the Pi into a PC or Mac via a USB cable. The gadget  in the Windows Device Manager picture shows this RNDIS Gadget connectivity between a Windows machine and a Raspberry Pi. The Problem Windows 11 and Windows 10 no longer auto-installs the RNDIS driver that makes magic happen. Windows recognizes that the Raspberry Pi is some type of generic USB COM device. Manually running W indows Update  or  Upd...
Read more

Understanding your WSL2 RAM and swap - Changing the default 50%-25%

Image
The Windows Subsystem for Linux operates as a virtual machine that can dynamically grow the amount of RAM to a maximum set at startup time.  Microsoft sets a default maximum RAM available to 50% of the physical memory and a swap-space that is 1/4 of the maximum WSL RAM.  You can scale those numbers up or down to allocate more or less RAM to the Linux instance. The first drawing shows the default WSL memory and swap space sizing. The images below show a developer machine that is running a dev environment in WSL2 and Docker Desktop.  Docker Desktop has two of its own WSL modules that need to be accounted for.  You can see that the memory would actually be oversubscribed, 3 x 50% if every VM used its maximum memory.  The actual amount of memory used is significantly smaller allowing every piece to fit. Click to Enlarge The second drawing shows the memory allocation on my 64GB laptop. WSL Linux defaul...
Read more

Almost PaaS Document Parsing with Tika and AWS Elastic Beanstalk

Image
The Apache Tika project provides a  library capable of parsing and extracting data and meta data from over 1000 file types.  Tika is available as a single jar file that can be included inside applications or as a deployable jar file that runs Tika as a standalone service. This blog describes deploying the Tika jar as an auto-scale service in Amazon AWS Elastic Beanstalk.  I selected Elastic Beanstalk because it supports jar based deployments without any real Infrastructure configuration. Elastic Beanstalk auto-scale should take care of scaling up and down for for the number of requests you get. Tika parses documents and extracts their text completely in memory. Tika was deployed for this blog using EC2 t2.micro instances available in the AWS free tier. t2.micro VMs are 1GB which means that you are restricted in document complexity and size. You would size your instances appropriately for your largest documents.   Preconditions An AWS account. AWS ac...
Read more