This circuit is intended to signal when a plant needs water. A LED flashes at a low rate when the ground in the flower-pot is too dry, turning off when the moisture level is increasing. Adjusting R2 will allow the user to adapt the sensitivity of the circuit for different grounds, pots and probe types.
This circuit was designed to provide that continuous light lamps already wired into a circuit, become flashing. Simply insert the circuit between existing lamp and negative supply.
Flashing frequency can be varied by changing R1 value in the 1M to 4M7 range. This circuit is very efficient when driving a small 3.2V incandescent lamp. In this case omit the LED and R3, connecting the bulb across Q2 Collector and positive supply, further reducing parts counting.
The basic circuit illuminates up to ten LEDs in sequence, following the rhythm of music or speech picked-up by a small microphone. The expanded version can drive up to ten strips, formed by up to five LEDs each, at 9V supply.
Alan Parekh designed a rotating LED display where the board can be seen rotating very quickly and a word appearing in mid air.
The LED Torch in Fig. 1 consumes just 24 mW, giving it more than80 times longer service from 4 AA alkaline batteries that is, up to one month continuous service. Although the torchs light output is modest, it is nonetheless quite sufficient to illuminate a pathway for walking.
This circuit uses the integrated circuit LM3909 perform be LED Flasher and Oscillator. For Drive LED give Flasher on off with Frequency 2Hz. For formed show of office equipment with Battery For battery 6V size Capacitors
Here is a new version of the classic color organ, where different color lights are triggered by different frequencies of sound, resulting in a display that flashes along to music. In this case the newer type high intensity LEDs-3000 - 5000mcd were used along with a very simple discrete transistor drive circuit.
This circuit operates a LED in pulsing mode, i.e. the LED goes from off state, lights up gradually, then dims gradually, etc.this gives an astonishing effect with
This schematic is a version of a simple 10 LED chaser. There is no 555 timer used .Instead, an oscillator made up of two sections of a 4011 NAND gate is employed. This chip is very inexpensive and extremely common.