Energy-efficient lighting

LED brightness regulator: K561LE5 schematic, 6–15 V supply

In large apartments and private houses, it is difficult in the evening and at night to walk along dark corridors or stairs and find the switch by touch to turn on the lighting. There is also an alternative — to buy autonomous “soft light” fixtures; they can be installed anywhere convenient for the owner. However, Read more…

If watering, then automatically

Auto watering & spraying for houseplants

I offer readers of our favorite magazine an automatic plant watering and spraying system of my own design, which has proven itself both indoors and in a greenhouse, winter garden, and flower bed. It consists of two interconnected subsystems: “sensor — water supply” (fig. 1) and an electronic control unit (fig. 2). While the first Read more…

Automatic incubator

Fig. 1. General view of the incubator

A compact incubator in which you can hatch turkeys and chickens, ducks and geese, operates from an AC power supply. The design automatically maintains the required temperature: chicken and turkey eggs are cooled twice a day, and waterfowl eggs — four times. In addition, the machine turns the eggs 180° every hour. If something fails Read more…

Metal detector

DIY Metal Detector: Circuit & Assembly Guide

This device helps detect hidden large metal objects at depths up to 0.6 m. It is needed by builders, gas service workers, and utility workers to search for metal manholes and covers that, during building construction or street reconstruction, ended up under a layer of earth, asphalt, or were covered by sand. With a metal Read more…

Safe with a secret

Cybernetic Safe Lock: DIY Build & Algorithm Guide

“Open Sesame” — with these words, the resourceful and brave Ali Baba opened the magic door to the cave with treasures. Let’s imagine that Ali Baba is solving a more difficult task — trying to open the door to another cave, the entrance to which is blocked by a magic barrel. It can rotate around Read more…

Electronic thermometer

DIY Electronic Thermometer: Circuit, Assembly, Calibration

This device can quickly and accurately measure, for example, the temperature of a human body, water, and air. An electronic thermometer is needed by agricultural workers to determine the temperature of grain, potatoes, and soil, and by medical workers. The thermometer consists of five main units: a temperature-to-frequency converter, a rectangular pulse generator, a pulse Read more…

Burn, fire!

IR flame alarm for fireplace & stove: DIY circuit, build guide

When heating a fireplace or sauna stove at a dacha with wood, the combustion process must be monitored from time to time: adding firewood, increasing draft, etc. The proposed electronic device can replace the “owner’s eye” and remind of this by signalling when the flame in the stove (firebox) diminishes. I experimented a bit and Read more…

Ultrasound against rodents

Ultrasound: Nature, Tech & DIY "Antigryzun" Rodent Repeller

Among elastic oscillations of air, ultrasound (from Latin ultra — beyond, more, above), inaudible to the human ear and with a lower frequency limit conventionally taken as 20 kHz, has long attracted special interest. Insects, bats, and even cetaceans make successful use of this natural gift: some for communication, others for hunting, others for locating Read more…