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The Autopilot using a Stamp — Parallax Forums

The Autopilot using a Stamp

ArchiverArchiver Posts: 46,084
edited 2000-03-22 20:22 in General Discussion
Hi all,
Regarding my last message about the Autopilot using light sensors, I
want to be able to build this myself and not get one off the shelf
already made (there's no fun in that), So if anybody knows the best
type of light sensor to use or maybe some sort of weighted pot, How do
you convert these measurements to output pulses to the servos.
Thanks in advance

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2000-03-22 17:24
    HI I am totally new to Pbasic and STAMPS but the system i am trying to use for
    my X-Y solar panel tracking system should be OK for your app.
    I would use silicon photocells for the light detection.
    They are diodes ( Alltronics.com has some very nice small ones ) and can best be
    used by connection to an op amp.. LM324 or ?
    The best way to connect them is to put them across the op-amp inputs and use a
    resistor
    to feedback current.. this current will exactly match the diode /light current
    and os you can adjust the sensitivity.
    For just a single plane as you describe you'll need 2 diodes set at about 90-120
    degrees .
    The outputs of the op amps can then goto a ADC (LTC1298 see page 357 of STAMP
    manual )and then as digital signals
    via a shiftin ( BS2 ) to the BS2. You then can do a simple routine :
    flylevel:
    if leftlight > rightlight then liftright
    liftright:
    liftR = out0 ' makes pin 0 same state as liftR
    liftR var bit
    liftR = 1 ' this will be an output to liftR that you put to a pin0
    ' pin0 going to 5.0 volts can then move a flap via a servo etc..
    you need to loop around this so the sensors keep looking for the
    difference. For stable flight you might need to put a PAUSE delay in the
    loop otherwise the plane might fly along "wagging" itself...



    Date sent: Wed, 22 Mar 2000 00:41:44 -0800
    From: "Paul" <paul.byrne@b...>
    To: basicstamps@eGroups.com
    Send reply to: basicstamps@eGroups.com
    Subject: [noparse][[/noparse]basicstamps] The Autopilot using a Stamp

    > Hi all,
    > Regarding my last message about the Autopilot using light sensors, I
    > want to be able to build this myself and not get one off the shelf
    > already made (there's no fun in that), So if anybody knows the best
    > type of light sensor to use or maybe some sort of weighted pot, How do
    > you convert these measurements to output pulses to the servos.
    > Thanks in advance
    >
    >
    >
    > -- Easily schedule meetings and events using the group calendar!
    > -- http://www.egroups.com/cal?listname=basicstamps&m=1
    >
    >


    ron... the motor man...
    Ronald Doctors
    http://www.members.home.net/rdoctors
  • ArchiverArchiver Posts: 46,084
    edited 2000-03-22 17:45
    I just wanted to point out that the RCtime command can read photodiodes
    directly, without need for an op-amp or ADC. For a tutorial, download--
    http://www.stampsinclass.com/downloads/em4.pdf

    -- Tracy Allen
    Electronically Monitored Ecosystems
    http://www.emesystems.com



    ----original message---->
    HI I am totally new to Pbasic and STAMPS but the system i am trying to use
    for my X-Y solar panel tracking system should be OK for your app.
    I would use silicon photocells for the light detection.
    They are diodes ( Alltronics.com has some very nice small ones ) and can
    best be used by connection to an op amp.. LM324 or ?
    The best way to connect them is to put them across the op-amp inputs and
    use a resistor
    to feedback current.. this current will exactly match the diode /light
    current and os you can adjust the sensitivity.
    For just a single plane as you describe you'll need 2 diodes set at about
    90-120 degrees .
    The outputs of the op amps can then goto a ADC (LTC1298 see page 357 of
    STAMP manual )and then as digital signals
    via a shiftin ( BS2 ) to the BS2. You then can do a simple routine :
    flylevel:
    if leftlight > rightlight then liftright
    liftright:
    liftR = out0 ' makes pin 0 same state as liftR
    liftR var bit
    liftR = 1 ' this will be an output to liftR that you put to a pin0
    ' pin0 going to 5.0 volts can then move a flap via a servo etc..
    you need to loop around this so the sensors keep looking for the
    difference. For stable flight you might need to put a PAUSE delay in the
    loop otherwise the plane might fly along "wagging" itself...



    Date sent: Wed, 22 Mar 2000 00:41:44 -0800
    From: "Paul" <paul.byrne@b...>
    To: basicstamps@eGroups.com
    Send reply to: basicstamps@eGroups.com
    Subject: [noparse][[/noparse]basicstamps] The Autopilot using a Stamp

    > Hi all,
    > Regarding my last message about the Autopilot using light sensors, I
    > want to be able to build this myself and not get one off the shelf
    > already made (there's no fun in that), So if anybody knows the best
    > type of light sensor to use or maybe some sort of weighted pot, How do
    > you convert these measurements to output pulses to the servos.
    > Thanks in advance
    >
    >
    >
    > -- Easily schedule meetings and events using the group calendar!
    > -- http://www.egroups.com/cal?listname=basicstamps&m=1
    >
    >


    ron... the motor man...
    Ronald Doctors
    http://www.members.home.net/rdoctors
  • ArchiverArchiver Posts: 46,084
    edited 2000-03-22 17:46
    Paul,

    Okay, this should keep you busy for a while...


    http://www.euronet.nl/users/ragman/robot1.html

    >Regarding my last message about the Autopilot using light sensors, I
    >want to be able to build this myself and not get one off the shelf
    >already made (there's no fun in that), So if anybody knows the best
    >type of light sensor to use or maybe some sort of weighted pot, How do
    >you convert these measurements to output pulses to the servos.

    Mike Hardwick, for Decade Engineering -- <http://www.decadenet.com>
    Manufacturer of the famous BOB-II Serial Video Text Display Module!
  • ArchiverArchiver Posts: 46,084
    edited 2000-03-22 20:22
    Very nice too, I can't use this approach as i have 2 many ins and outs for a
    STAMP so i needed to
    MUX both the A/D in and the control bits out.
    Might be good for a RC plane though!
    Thanks for pointing the article out.

    Date sent: Wed, 22 Mar 2000 12:45:58 -0500
    From: Tracy Allen <emesys@c...>
    To: "INTERNET:basicstamps@eGroups.com" <basicstamps@eGroups.com>
    Send reply to: basicstamps@eGroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: The Autopilot using a Stamp

    > I just wanted to point out that the RCtime command can read photodiodes
    > directly, without need for an op-amp or ADC. For a tutorial, download--
    > http://www.stampsinclass.com/downloads/em4.pdf
    >
    > -- Tracy Allen
    > Electronically Monitored Ecosystems
    > http://www.emesystems.com
    >
    >
    >
    > ----original message---->
    > HI I am totally new to Pbasic and STAMPS but the system i am trying to use
    > for my X-Y solar panel tracking system should be OK for your app.
    > I would use silicon photocells for the light detection.
    > They are diodes ( Alltronics.com has some very nice small ones ) and can
    > best be used by connection to an op amp.. LM324 or ?
    > The best way to connect them is to put them across the op-amp inputs and
    > use a resistor
    > to feedback current.. this current will exactly match the diode /light
    > current and os you can adjust the sensitivity.
    > For just a single plane as you describe you'll need 2 diodes set at about
    > 90-120 degrees .
    > The outputs of the op amps can then goto a ADC (LTC1298 see page 357 of
    > STAMP manual )and then as digital signals
    > via a shiftin ( BS2 ) to the BS2. You then can do a simple routine :
    > flylevel:
    > if leftlight > rightlight then liftright
    > liftright:
    > liftR = out0 ' makes pin 0 same state as liftR
    > liftR var bit
    > liftR = 1 ' this will be an output to liftR that you put to a pin0
    > ' pin0 going to 5.0 volts can then move a flap via a servo etc..
    > you need to loop around this so the sensors keep looking for the
    > difference. For stable flight you might need to put a PAUSE delay in the
    > loop otherwise the plane might fly along "wagging" itself...
    >
    >
    >
    > Date sent: Wed, 22 Mar 2000 00:41:44 -0800
    > From: "Paul" <paul.byrne@b...>
    > To: basicstamps@eGroups.com
    > Send reply to: basicstamps@eGroups.com
    > Subject: [noparse][[/noparse]basicstamps] The Autopilot using a Stamp
    >
    > > Hi all,
    > > Regarding my last message about the Autopilot using light sensors, I
    > > want to be able to build this myself and not get one off the shelf
    > > already made (there's no fun in that), So if anybody knows the best
    > > type of light sensor to use or maybe some sort of weighted pot, How do
    > > you convert these measurements to output pulses to the servos.
    > > Thanks in advance
    > >
    > >
    > >
    > > -- Easily schedule meetings and events using the group calendar!
    > > -- http://www.egroups.com/cal?listname=basicstamps&m=1
    > >
    > >
    >
    >
    > ron... the motor man...
    > Ronald Doctors
    > http://www.members.home.net/rdoctors
    >
    >
    >
    > eGroups.com home: http://www.egroups.com/group/basicstamps
    > http://www.egroups.com - Simplifying group communications
    >
    >
    >
    >


    ron... the motor man...
    Ronald Doctors
    http://www.members.home.net/rdoctors
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