In spot welding mode

DIY spot welder for sheet steel with OSM-1.0 transformer

The welding apparatus I built is a modernized version of a device that has proven itself well in practice; its description and sketches were published in the magazine Modelist-Konstruktor No. 3, 1966. The main point is that the new “welder” is significantly more powerful than its predecessor, and simpler to build and operate. Without any Read more…

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…

Fireplace for bees

SKVU: winter hive heating and convective ventilation system

Research by scientists and beekeepers’ experience show that with adequate quality feed and careful management, flying honey producers tolerate wintering well even in severe frost. For a weakened bee colony in cold weather, the trouble is less the low temperature than high humidity, when frames and the inner surfaces of hives grow mold, and the 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…

My assistant

DIY Aquarium Automaton: Automatic Control Device

Summer vacation time is approaching. To the numerous concerns related to preparing for the upcoming vacation, aquarium owners have one more: how to provide everything necessary for the underwater inhabitants during the owner’s absence. If you have no one to entrust your aquarium to, entrust its care to an automaton (Fig. 1) and rest peacefully. 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…

How to change the voltage?

Step-Down Transformer 4-12V: Complete DIY Guide

The simplest electrical devices that our magazine offered to beginners work from a 3336L battery for a pocket flashlight. But it cannot provide much energy: after several hours of continuous operation, the battery “runs down”, and then it needs to be replaced. It is much more convenient to power homemade devices from a constant source 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…