Low noise electret MIC pre-amplifier module can be used to sense sound signals and to amplify it to a high voltage. This module can be used with a power amplifier to make MIC and speaker circuit. This can also be used as sound sensor module.
Operating voltage – 9V
Working of low noise electret MIC pre-amplifier module : https://haberocean.com/2019/08/working-of-low-noise-electret-mic-pre-amplifier-module/
Running LED or Johnson counter module of 25 LEDs designed using 4017 IC. Programming is not required for the working. Module can be worked using astable multi vibrator designed using 555 timer IC. Watch the video demonstration to get the working of module.
Purchase from Amazon : http://www.amazon.in/dp/B07YBD33G9?ref=myi_title_dp
Controlling using Arduino UNO, Circuit and program at : https://haberocean.com/2019/12/controlling-siren-module-from-arduino-uno/
Manually controlling UM3561 siren module, circuit at : https://haberocean.com/2020/01/manually-controlling-um3561-siren-module/
Purchase from Amazon at : http://www.amazon.in/dp/B082T3GFF2?ref=myi_title_dp
It is a temperature monitoring system over WiFi using ESP8266. Temperature can be monitored on any android or IOS device through a web browser. This device will help you to set the lower threshold temperature and upper threshold temperature remotely from your mobile device through WiFi. Any low voltage device can be connected at the output. This device will turn on when temperature is above upper threshold and turns off when the temperature is below lower threshold. High voltage devices can be connected through relay. Also, there is an option provided to set the delay after which the output device will turn ON or OFF when the temperature is above or below the threshold values.
Circuit and program at : https://haberocean.com/2020/01/temperature-monitoring-and-device-control-system-over-wifi/
ESP8266 programmer circuit at : https://haberocean.com/2020/01/esp8266-esp-12f-esp-12e-programmer-circuit/