In a project I wanted to measure the amount of light in the room for controlling the backlight of a Tft display. The project uses a Raspberry Pi, which sadly don't have any analog inputs. In this case one can use a Ldr or a photo transistor with a capacitor. The principle is that you set a pin as output and make it high. This charges the capacitor. You then set the pin as input and measure the time until the Pi consideres the input to be low. The time this takes depends on how much light the detector is exposed to and will be a value depending on how much light there is in the room.
Electric tea lights are nice but they have a great disadvantage. There are small batteries in the base which dont last long and you have to replace them often. A modification is to remove the small batteries and add an external battery pack. The tea lights work on 3 volt, so two AA:s, rechargeable or not, will do.
The goal of this project is to measure the light level in a room and send the value to a web server. One difficulty here is the lack of an ADC-pin on the ESP01 that is used. This is solved by letting a capacitor discharge through an IR-transistor, an idea taken from Pololu.
The goal of this project is to build a unit with four relays that can be controlled via Wifi. The components are mainly a ESP-03 wireless module, a ready-built relayboard and a 3V3 regulator.
I start by flashing firmware found here.
Then I can use the Arduino IDE to program the ESP. Ch_pd is connected to Vcc and Gpio15 to ground. To program, Gpio0 is connected to ground while the power is cycled.
In the bedroom we have a portable AC to cool of the room. It creates some noice, and therefor we prefer
First flash the ESP8266 with the Nodemcu firmware using this guide: http://www.whatimade.today/flashing-the-nodemcu-firmware-on-the-esp8266-linux-guide/.
Then install Esplorer, a Java tool to work with the Esp:
More info coming soon.