If you go to most supermarkets today you will see plug in mains powered digital programmable timers. These are designed to be used to automatically turn lights on and off, to turn washing machines on when you are out and so on. Prices start from as little as 5 pounds ($10) and these products are very feature rich often offering full seven-day programming and multiple
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on-off cycles per day. Sadly these mass-produced units are only designed for mains powered devices. If you want to purchase a 12V Programmable Timer Switch you`ll find them to be feature-poor and very expensive (read linked-to article to find out more). In our article Convert Thermostat to 12V Timer Switch we showed how a £20 battery powered timer thermostat could be converted easily to operate as a programmable timer relay switch. Unfortunately such a thermostat can be programmed with only one on-off cycle per day, and the shortest on (or off) interval it can provide is 15 minutes. In this article we will show you how a cheap supermarket bought mains timer can be converted to operate on low voltage and control (i. e. switch on and off at programmed times) low voltage devices. The timer pictured above is a TE7 7 Day Electronic Timer marketed within Tesco`s energy saving promotion and priced at just £8. This is the timer we will convert in this article. NEW - After publishing this article, we discovered that the exact same timer is also sold by Sainsburys for around £8, but this time branded as Masterplug 7 Day Electronic Timer. With this branding it is also sold in the UK at Halfords, Woolworths, Focus DIY, and numerous other outlets. The display on a programmable digital timer is not powered directly by mains electricity. Instead a small 1. 2V NiMH rechargeable backup cell is kept charged, and the display and electronics...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
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The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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