The first test circuit (see figure 5) is about the simplest circuit that can be designed around the device. The sensor is drawn in the schematic as if you are looking through the top of the sensor to the 12 leads below. The circuit uses four LED`s for display. Each cardinal position on the compass lights one LED. The intermediate directions light
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two LED`s as shown in figure 6. Notice that all the number 2 ground leads are tied together. As are the number 1 leads connected to +5 volts Vcc. The sensor will operate supply voltages from 5 to 18 volts. I used a 7805 to regulate the 9V battery to a constant 5 volts. The LED`s used in the circuit are red micro-miniature type that operate using little current. The 1K resistors limit the current flowing through the LED`s to about 5 mA. The sensor is dampened to approximate the speed of a liquid filled compass. The dampening prevents over swinging the direction. In addition the built in hysteresis prevents flutter when near a switching direction. The 1490 device is sensitive to tilt. Any tilt greater than 12 degrees will create directional errors. Figure 6, shows the minimum components of figure 5 mounted and soldered to the pc board, figure 7. Q1 is a 7805-voltage regulator. R1 through R4 are 1/8 watt 1K resistors. Four sub-miniature LED`s are soldered into the B0 through B4 positions, with the positive lead of the LED orientated on the right side with the board as shown in figure 4. Capacitors C3 and C4 are 22 uF capacitors. 9V battery cap is wired into the Vin positions, and finally a switch is wired on to the pcb in the lower left hand corner. When I first assembled this circuit onto the board it did not function properly. The compass did not respond, as it should. I tracked the problem to the switch that is in close...
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.....
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