Designing a circuit that will use a combination of switches and resistors to allow a microcontroller to identify which switch was pressed based on the voltage read and perform a switch-specific action. The design that I`ve come up with involves using a transistor to activate a relay, which powers the microcontroller. When the microcontroller is powered, it pulls a pin high to take over powering the relay. When the action is finished
Click here to download the full size of the above Circuit.
the microcontroller pulls the pin low, deactivating the relay and cutting power to the microcontroller. I`ve tested the circuit with one switch and a voltage divider to simulate the largest resistor/lowest voltage combination from my switch array. The voltage that I`ve calculated at the transistor is 1. 6 V, and the current is 0. 017 mA. The high resistor values are necessary since I need approximately 0. 2 V differential between switches. The problem is that the transistor is not being activated (it works if I feed it 5V directly). My question: Is this because the current is too low How would I go about rectifying this (other than decreasing resistances) If there is a better approach to this problem, I`d love to hear it also. This is a circuit for a picture frame that will do specific actions depending on the button that is pressed. This will be battery-operated using 6 D-cell batteries, mounted on the wall. I`d like to get months if not years of operation out of it before having to replace the unit. My Arduino with an attached shield (with using a MAX667 power supply rather than the stock one) consumes 45 mA at low power. The stock Arduino doesn`t go into low power mode although with a programmer the chip can be modified to go into low power mode and consume nA of current. At 45 mA, the batteries will last about 11 days (266 hours for a 12000 mAh battery). Hence the requirement that the resistive ladder turn on the...
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: