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CDMaxibug v5

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  • Wilf Rigter
    OK here is CD Maxibug v1. It is based on the MaxiBug by Math Vos. If I had only taken some time to read his excelent tutorial (
    Message 1 of 2 , Mar 25, 2003
      OK here is CD Maxibug v1. It is based on the MaxiBug by Math Vos. If I had
      only taken some time to read his excelent tutorial (
      http://home.wanadoo.nl/m.m.avos/maxibug.htm ) in which he describes feeding
      stations etc, I would not have wasted my time reinventing the wheel.

      Having said that, maxibug is not perfect: it churns its wheels while
      feeding and does not back out of the feeding station when full. So here is
      CDMaxiBug v5. It uses just a few more parts but has powerful and efficient
      motor drivers, its motors are off while feeding and it backs up when full.

      The CD Maxibug v5 uses just one 74AC240 chip. The motor drivers are of the
      Current Dump variety which do not waste any base current and can handle a
      wide range of motors. The voltage comparator uses two inverters with
      positive feedback to make a Schmitt trigger circuit. The 1K feedback
      potentiometer has a small value to control the LED current when changing
      state. A steady LED indicates low supply voltage and the phototropic mode.
      In addition, the comparator uses an FLED to provide efficient voltage
      sampling to minimize the 74AC supply current associated with a slow changing
      analog input voltage. Note that the schmitt trigger configuration does not
      exclude the analog level from the input but does insure positive switching
      when triggered and reset.

      Maxibug is designed to work with a 5V feeding station that charges Maxibug's
      super cap used for energy storage. The cap must be rated 5.5V and is
      usually constructed with two equal capacitance 2.5V super caps connected in
      series to provide the voltage rating. The charging current is limited by a
      22 ohm resistor in series with the feeding electrodes.
      A bright light beacon just above the feedingstation electrodes is designed
      to attract and to line up maxibot's charging electrodes during the incoming
      trajectory. The physical design of the feeding station is up to the reader
      and will require considerable ingenuity to perfect. One consideration for
      "jacking" into the charger is to avoid closing the reverse switch when in
      the docking bay since that may cause it to back out before the charging
      contacts mate. Once contact is made MaxiBug v5 charging interface circuit
      applies +V to pin 19 and automatically turns off the B section motor drivers
      for a low power standby mode. The Maxibot charger interface circuit also
      charges the reverse delay circuit through a diode so that when the motors
      are turned on the maxibug will back up for the duration of the reverse
      delay.

      The super cap charges up fairly rapidly while the storage cap voltage is
      monitored by the voltage comparator.
      The Maxibug v5 comparator is designed so that when the output is low, the
      feedback pot forces several milliamps of current through the reference LED
      to set the forward voltage to about 1.8V. The pot should be adjusted to set
      the trigger level close to 5.5V . Use a 6V supply (or battery) for the
      charging station. Turn the wiper of the feedback pot all the way to wards
      the LEDs. When the cap is fully charged (~5.5V) slowly adjust the pot until
      the circuit triggers. Once triggered, the comparator applies a low voltage
      to pin 19 to enable the B section motor drivers and Maxibug v5 disconnects
      from the charger and backs out of the feeding station.

      When fully charged maxibug is photophobic and avoids bright light. The FLED
      and LED will both flash as the comparator samples the lower threshold
      voltage with each FLED current pulse. When the voltage drops to about 4V the
      comparator switches low again and LED turns on solid. MaxiBug now seeks out
      the beacon.

      The circuit is attached and a layout will follow.

      enjoy

      wilf



      ----- Original Message -----
      From: "Wilf Rigter" <wrigter@...>
      To: <beam@yahoogroups.com>
      Sent: Monday, March 24, 2003 7:14 PM
      Subject: Re: [beam] response to wilf- (um, is this safe?)


      > Hi John-Isaac,
      > I enclose the complete mazibug v4a schematic and layout more as an example
      > of a CD bridge application and as the starting point for a new mazibug
      > design that can "jack" into an e-Station and reverses when full.
      >
      > regards
      >
      > wilf



      ---
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    • Adam
      Would it be easy to use two of those little rechargable RC car batteries in series to replace the big cap? then the bot could venture farther from the feeding
      Message 2 of 2 , Mar 25, 2003
        Would it be easy to use two of those little rechargable RC car
        batteries in series to replace the big cap? then the bot could
        venture farther from the feeding station after every charge, it
        might take a little while longer to charge, but i would think that
        the bot would show more complex behaviors if it were left out
        to "play in the dark" for longer periods of time.

        Adam
        (by the way, really cool scheme, can't wait to build it)
        --- In beam@yahoogroups.com, "Wilf Rigter" <wrigter@d...> wrote:
        > OK here is CD Maxibug v1. It is based on the MaxiBug by Math Vos.
        If I had
        > only taken some time to read his excelent tutorial (
        > http://home.wanadoo.nl/m.m.avos/maxibug.htm ) in which he
        describes feeding
        > stations etc, I would not have wasted my time reinventing the
        wheel.
        >
        > Having said that, maxibug is not perfect: it churns its wheels
        while
        > feeding and does not back out of the feeding station when full. So
        here is
        > CDMaxiBug v5. It uses just a few more parts but has powerful and
        efficient
        > motor drivers, its motors are off while feeding and it backs up
        when full.
        >
        > The CD Maxibug v5 uses just one 74AC240 chip. The motor drivers
        are of the
        > Current Dump variety which do not waste any base current and can
        handle a
        > wide range of motors. The voltage comparator uses two inverters
        with
        > positive feedback to make a Schmitt trigger circuit. The 1K
        feedback
        > potentiometer has a small value to control the LED current when
        changing
        > state. A steady LED indicates low supply voltage and the
        phototropic mode.
        > In addition, the comparator uses an FLED to provide efficient
        voltage
        > sampling to minimize the 74AC supply current associated with a
        slow changing
        > analog input voltage. Note that the schmitt trigger configuration
        does not
        > exclude the analog level from the input but does insure positive
        switching
        > when triggered and reset.
        >
        > Maxibug is designed to work with a 5V feeding station that charges
        Maxibug's
        > super cap used for energy storage. The cap must be rated 5.5V and
        is
        > usually constructed with two equal capacitance 2.5V super caps
        connected in
        > series to provide the voltage rating. The charging current is
        limited by a
        > 22 ohm resistor in series with the feeding electrodes.
        > A bright light beacon just above the feedingstation electrodes is
        designed
        > to attract and to line up maxibot's charging electrodes during the
        incoming
        > trajectory. The physical design of the feeding station is up to
        the reader
        > and will require considerable ingenuity to perfect. One
        consideration for
        > "jacking" into the charger is to avoid closing the reverse switch
        when in
        > the docking bay since that may cause it to back out before the
        charging
        > contacts mate. Once contact is made MaxiBug v5 charging interface
        circuit
        > applies +V to pin 19 and automatically turns off the B section
        motor drivers
        > for a low power standby mode. The Maxibot charger interface
        circuit also
        > charges the reverse delay circuit through a diode so that when the
        motors
        > are turned on the maxibug will back up for the duration of the
        reverse
        > delay.
        >
        > The super cap charges up fairly rapidly while the storage cap
        voltage is
        > monitored by the voltage comparator.
        > The Maxibug v5 comparator is designed so that when the output is
        low, the
        > feedback pot forces several milliamps of current through the
        reference LED
        > to set the forward voltage to about 1.8V. The pot should be
        adjusted to set
        > the trigger level close to 5.5V . Use a 6V supply (or battery)
        for the
        > charging station. Turn the wiper of the feedback pot all the way
        to wards
        > the LEDs. When the cap is fully charged (~5.5V) slowly adjust the
        pot until
        > the circuit triggers. Once triggered, the comparator applies a
        low voltage
        > to pin 19 to enable the B section motor drivers and Maxibug v5
        disconnects
        > from the charger and backs out of the feeding station.
        >
        > When fully charged maxibug is photophobic and avoids bright light.
        The FLED
        > and LED will both flash as the comparator samples the lower
        threshold
        > voltage with each FLED current pulse. When the voltage drops to
        about 4V the
        > comparator switches low again and LED turns on solid. MaxiBug now
        seeks out
        > the beacon.
        >
        > The circuit is attached and a layout will follow.
        >
        > enjoy
        >
        > wilf
        >
        >
        >
        > ----- Original Message -----
        > From: "Wilf Rigter" <wrigter@d...>
        > To: <beam@yahoogroups.com>
        > Sent: Monday, March 24, 2003 7:14 PM
        > Subject: Re: [beam] response to wilf- (um, is this safe?)
        >
        >
        > > Hi John-Isaac,
        > > I enclose the complete mazibug v4a schematic and layout more as
        an example
        > > of a CD bridge application and as the starting point for a new
        mazibug
        > > design that can "jack" into an e-Station and reverses when full.
        > >
        > > regards
        > >
        > > wilf
        >
        >
        >
        > ---
        > Outgoing mail is certified Virus Free.
        > Checked by AVG anti-virus system (http://www.grisoft.com).
        > Version: 6.0.463 / Virus Database: 262 - Release Date: 3/18/2003
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