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Help!!! Voltage Regulation!!! — Parallax Forums

Help!!! Voltage Regulation!!!

BS2FreakBS2Freak Posts: 5
edited 2008-04-10 16:53 in BASIC Stamp
Hello. I am new to Basic Stamps. I have made a robot similar to Boe-Bot. I have an Ultrasonic, 3 irda sensors, one lcd and three servos on it. I would like to know if it is possible to provide power from and external source in the LCD or in the Ultrasonic. I have created a mini power supply from the Education board schematics but both the LCD and the Ultrasonic don't have a normal behavior. They power up and seem to work normal but they don't. I've used an LM2940CT-5.0 P+ regulator and a Capacitor 1000uF/10V. The LCD power up and can do the test in the test mode but cannot print any characters. The Ultrasonic measures the distance but with breaks. Any help it would be appreciated.

Sorry for my poor English

Comments

  • marzec309marzec309 Posts: 146
    edited 2008-04-09 23:03
    First off make sure all your grounds are connected. Share a common ground with all your Power Supplies. Second make sure your battery voltage is greater than 5.5 Volts preferably 6.0 Volts. Third if you are pulling more than 1/2 amp (500mA) you need a heat sink. Also make sure your max current isn't exceeding 1 amp. You have a lot of things running off that regulator and its possible you are. Lastly double check that your power supplies ground is connected to the BOE's ground. More then likely you don't causing communication problems.
  • BS2FreakBS2Freak Posts: 5
    edited 2008-04-10 08:53
    I use a heatsink and i supply voltage more than 7 volts from a 9 volt battery. However i don't know how to ground the whole thing.
  • BS2FreakBS2Freak Posts: 5
    edited 2008-04-10 09:07
    Ok i used this schematic and my real circuit is this. I 've added a heatsink too that cannot be seen in the photo
    power.JPG
    314 x 148 - 6K
    power2.JPG
    3072 x 2304 - 2M
  • David H.David H. Posts: 78
    edited 2008-04-10 16:19
    BS2Freak,
    Just run a wire from your board, where your -9v line from your battery hooks up. This will be the ground. Connect that to your other grounds you mentioned.
    Good luck

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    David


    There are 10 types of people in this world,...
    Those that understand binary numbers, and those that don't!!!
  • BS2FreakBS2Freak Posts: 5
    edited 2008-04-10 16:33
    So i need to run a wire from the Vss point to the -9v pole right? Thanks!!!!!
  • BS2FreakBS2Freak Posts: 5
    edited 2008-04-10 16:53
    I 've connected the Vss to the -9Volts of the battery and it workeD!!!!Thanks a lot!!!
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