magnet


Posted on Feb 6, 2014

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


magnet
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...




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Wide band 10MHz 500MHz RF amplifier
    um3561 high temperature detector circuit diagram
    BATTERY MONITOR
    24v 7ah lead acid battery charger
    Car Boot Lamp Warning (ICM7556)
    The many DC to DC converters using IC-555
    VLF Whistler Reception
    Fire siren



    Top