Powering the LED with a 3V CR2032 battery and hoping I could extend the battery life by making the LED blink instead of having it on all the time. The 555 timer one, with large value resistors in the voltage divider, is probably the best. It might need an extra transistor to handle the 100ma. pjc50 Dec 17 `12 at 15:04 It might be useful to know how often do you need your led to blink, and how long
Click here to download the full size of the above Circuit.
should it stay on. And you might wand to add further details about your specific project. Vladimir Cravero Dec 17 `12 at 16:15 555`s operating current is too large to be powered by a CR2023. If you really want to use a 555, instead use 7555, a CMOS variant of 555 timer. Chetan Bhargava Jan 6 `13 at 23:42 The comment above is right. "555" and "energy efficient" are like a fist and a face. When they meet, nothing good happens. Jonny B Good Jan 7 `13 at 11:09 You guys should probably take this to chat or form it into an answer. long comment chains are usually discouraged because it makes it hard for future readers to glean the actual answer. Toby Lawrence Jan 8 `13 at 16:53 As several of the answers so far have dispensed with the 100 mA LED drive current requirement, limiting it instead to the 20 to perhaps 50 mA that typical microcontrollers will safely sink or source, here are some minimal, high efficiency solutions within the same current constraints. Bowin M34-2H is a 3-pin part that will flash an LED at 2 Hz with 25 mA current. It contains an internal RC oscillator, with +/- 20% tolerance, hence not terribly precise. The pin-out and application circuit from the datasheet: This 8-pin TSSOP part can be "trained" with a sequence of up to 3 blinking elements, and will then continue to blink as trained. The programming connection can be removed after training, and this programming is achieved via a single signal line from any...
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....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
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.....
characters left: