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Category Archives: ESP8266

This winter I noticed several times that the temperature at our church was not where it should be. Either the heat was on on a day when it was not in use or there was a chill on Sunday morning. Ours is not a large church and the thermostat is not out in the open. I do not suspect that people are altering the temperature so it could be that the system is having issues. I needed data to understand what is happening and to possibly take action.

esp201_dht11

ESP201 (white), DHT11 (blue), 6-12vdc to 3.3vdc converter (black)

I put together a couple of sensors using an ESP-201 (esp8266) and a DHT11. The DHT11 is not very accurate as compared to a DS1820, but it is good enough for my purposes.  I wrote a simple program for the ESP201 that will connect to the WiFi, read the temperature and send it via MQTT. This is repeated every 10 minutes.

On my server I have MQTT and Node-Red installed. I have setup the Node-Red to capture the temperature readings to a MySQL database for future analysis. I have also created a simple status page to see what the temperature readings are. Future plans would be to send an alert if the temperature is out of bounds.

Future enhancements might focus on monitoring the HCVAC system for run-time and energy consumption.

NodeRed screenshot

Node-Red screen shot

coop-lightsensor

Light sensor

Vacation time was coming up and we needed a way to open and close the chicken coop. This project design began as an analog system with an automotive power window motor control (H-Bridge) and a couple of alarm door switches. However, the switches were of the normally open (NO) type. I needed normally closed (NC). We decided that rather than ordering NC switches it’d be “easier” to use an ESP8266 to control a relay module and provide real time status via wifi. An RTC module rounded out the hardware. This was a rather large shift from the original design … cool.

coop-motor

Cordless screwdriver

I had acquired a Black&Decker rechargeable screwdriver from a thrift store sometime in the past and this became the basis of our motor. It has a docking station which made it convenient for mounting. For the brains of the operation I used a NODEMCU 0.9 that I had laying around. I found two alarm reed NO switches that would make the limit sensors. A photocell for daylight detection and a surplus power brick that has 12VDC & 5VDC outputs. Some 2×4 lumber and a small piece of plywood for the door. A short amount of kite string is used to lift and lower the door.

I cut the the plywood into a 12″ x 18″ door. The 2×4 was cut into a frame with a notch to allow the door to slide up and down. The notch was cut using a router with a 3/4″ bit. A 1″ hole was drilled on the top of the frame to allow the string to freely move the door up and down.

I found an existing Arduino program on github that looked like I could use as a starting point. After a number of changes I was able to get a functioning unit. We installed it into the chicken coop and after a few days of beta testing we opened the hole and went live with it. The chickens took to it right away.

For my software I chose to use the ESP8266 instead of the ESPDUINO board, add a motor run timeout, & door sensor validation. Version 2 will have OTA updates and an LCD display.

coop-cpucoop-relaycoop-door