After reading Robert`s article, I immediately wanted to build this project so I ordered an HMC 1001 sensor and started breadboarding the circuit. As it turns out, there were a couple errors in the schematic that appeared in Sport Rocketry. I took Robert`s design apart and did a bit of redesigning to make it work. There has since been a correction
Click here to download the full size of the above Circuit.
published, but I had already come up with a much simpler circuit that works perfectly. Instead of trying to amplify then compare the outputs, I simply used a single op-amp as a comparator right off the magnetic sensor. Like the original, this drives a Field Effect Transisor to fire a flashbulb (or e-match) circuit. I also found that the voltage regulator really isn`t neccessary. The components are rated for up to 12 volts, so a 9 volt battery could be used to power everything without having the 5 volt power supply from the regulator. Be cautious as the HMC 1001 can be damaged if it sees more than 12 volts. According to Honeywell, the circuit performs better with a 5 volt supply, so I have left the regulator in this schematic. Another option on the power supply is to use the 544 battery. This is a small 6 volt battery found in the photo section. The battery is a little smaller than an "N" cell and measures about 1/2" diameter and 1" long. They are also available in Lithium. I built a circuit without a voltage regulator using a single Energizer 544 battery. It was able to fire the smaller flashbulbs taken from flash cubes very well, but didn`t have the power to handle the larger AG-1 flashbulbs. Of course it was easy to simply replace that battery with a standard 9 volt and it will fire the AG-1 bulbs just fine. I haven`t done any testing with electric matches or any other type of ignitor. For the serious weight conscious...
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: