Activities/Turtle Art/Using Turtle Art Sensors: Difference between revisions

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Standard 3.5mm 2-pin switched mono microphone jack; selectable 2V DC bias; selectable sensor-input mode (DC or AC coupled); selectable +20dB boost.

On the XO-1, mono data is measured, the left channel, the tip (usually the red wire). The XO-1.5 ~~and the~~ XO-1.75 can read both the left and right channel.

On the XO-1, mono data is measured, the left channel, the tip (usually the red wire). The XO-1.5, XO-1.75, XO-3 and XO-4 can read both the left and right channel. (Currently on the XO-1.75, XO-3 and XO-4 stereo input is disabled).

The XO-1 is protected at the input by a 5V zener diode. The allowable input is -0.5V to 5V. Inputs outside this range will cause excessive current and damage. Even a single 1.5V battery can cause damage if connected reverse polarity.

The XO-1 is protected at the input by a 5V zener diode. ([http://wiki.laptop.org/go/File:XO-1_Schematics.pdf 1]) The allowable input is -0.5V to 5V. Inputs outside this range will cause excessive current and damage. Even a single 1.5V battery can cause damage if connected reverse polarity.

The XO-1.5 is protected by a resistor,(1/16W 470 ohm SMD0402) and a pair of diodes to ground and to +3.3V which should protect -6V to +9V continuously, and up to higher voltages for shorter periods of time.

The XO-1.5 ( [http://wiki.laptop.org/go/File:XO-1.5_Schematics_rev_G.pdf 2] [http://wiki.laptop.org/go/File:XO-1.5_Schematics_rev_I.pdf 3] [http://wiki.laptop.org/go/File:XO-1.5_Schematics_rev_M.pdf 4] )and XO-1.75 (XO-3 and XO-4 presumably too) are protected by a resistor,(1/16W 470 ohm SMD0402) and a pair of diodes to ground and to +3.3V which should protect -6V to +9V continuously, and up to higher voltages for shorter periods of time.

~~The XO-1.75 also has the 470 ohms series resistor to the 2 diodes. If the resistor has the same wattage then the limits are the same~~.

For the XO-1, the addition of a 150k ohm series resistor would (I expect, no guarantee) give a reduced sensitivity in voltage mode (0-4V) but allow inputs to +- 100V without damage. Input impedance in resistance, volume and pitch modes is much lower but a 1k ohm series resistor should still allow inputs to +-12V.

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<i> 680 ohm series resistor on a 3.5mm audio plug</i>

Test leads with a zener diode and series resistor would expand the safe range for the XO1.5 ~~and~~ XO1.75.

Test leads with a zener diode and series resistor would expand the safe range for the XO1.5, XO1.75, XO-3 and XO-4.

Damage can also be caused by applying voltages between the grounds of any of the external sockets.

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===XO-1.75===

Two channels

Two channels, -0.3V to 3V, input impedance 4k ohms to a 3V bias, (models SKU204+ *) . At the time of writing, as a workaround to a bug with dual channels, apply the input to both channels, only a mono reading is available.

-3V to +3V, input impedance 1k ohm to a +3V bias, model SKU199

(* A small number of pre-production laptops were built with -3V to +3V input range and input impedance 1k ohm to a +3V bias, eg. model SKU199. Turtle Blocks V141 and previous is correctly calibrated for these laptops but not for production laptops)

-0~~.3V~~ to 3V, ~~imput impedance 4k ohms~~ to a ~~3V bias~~, ~~models SKU204+~~ to ~~be confirmed~~

===XO-4===

Two channels, 0 to 3V. At the time of writing, as a workaround to a bug with dual channels, apply the input to both channels, only a mono reading is available.

==Resistance Mode==

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===XO-1.75===

zero ohms to open circuit

Two channels, zero ohms to open circuit. At the time of writing, as a workaround to a bug with dual channels, apply the input to both channels, only a mono reading is available.

===XO-4===

Two channels, zero ohms to open circuit. At the time of writing, as a workaround to a bug with dual channels, apply the input to both channels, only a mono reading is available.

==Pitch Mode==

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== RC time constant ==

IT IS RECOMMENDED THAT A SERIES PROTECTION RESISTOR BE BUILT INTO THE PHONO PLUG AND LEADS IF USING AN EXTERNAL VOLTAGE

IT IS RECOMMENDED THAT A SERIES PROTECTION RESISTOR BE BUILT INTO THE PHONO PLUG AND LEADS IF USING AN EXTERNAL VOLTAGE WITH THE XO-1

[[File:Rc cct.jpg]]

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R = T/C

= 0.14 /(4x10^-6) = 35k

[[File:Rc-time.jpg]]

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[[File:RC data to clip.jpg]]

See also a similar experiment which uses the [[Activities/TurtleBots#Buti.C3.A1|USB4Butia]] board (in Spanish) http://youtu.be/eewFtOHX5-Q and http://youtu.be/KmNwC1qBhtA

==Voltage-current relationship==

Some devices including light bulbs have non-linear voltage current relationships. In this experiment, the V-I graph of a light bulb is drawn using the stereo input of the XO-1.5.

[[Image:VIgraph.jpg|250px]] [[Image:VI Turtle Art.png|400px]]

[[File:Turtle Art Activity VI.ta]]

The light bulb and resistor were chosen thus. The maximum measurable input of the XO-1.5 is +3V, at maximum you want approximately 1.5V across the resistor and 1.5V across the bulb, the bulb should be near full brightness. A 2.8V 0.85A torch/flashlight bulb was used. The estimated resistance of the bulb is V/I, 2.8V/0.85A = 3.3 ohms, chosing from resistors at hand, trial and error found 2.2 ohms was OK. The power rating of the resistor is V*V/R, 1.5*1.5/2.2 = 1.02W, a resistor of 1W or higher rating is required.

A laboratory power supply was used in this experiment. It is safest if its output is within the maximum allowable voltage range of the XO-1.5, -6 to +9V. Low cost options would include a selection of dry cells in varying states of discharge. It may be practical to construct a variable resistor using a pencil lead.

The X axis is voltage across the bulb, voltage2 - voltage, the Y axis is the current which is proportional to the voltage across the resistor or the L channel voltage.

See also http://youtu.be/37vJEUr5nRI and http://www.youtube.com/watch?v=_iSXHsGvLaY (in Spanish) for experiments plotting linear and nonlinear V-I relationships using the [[Activities/TurtleBots#Buti.C3.A1|USB4Butia]] board.

==The XO as an audio amplifier==

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http://www.youtube.com/embed/l3vKVTW1LQA

One laptop running Turtleart is used to generate a 3kHz audio tone. The second laptop, XO-1.5 or higher, graphs the output of 2 microphones with Measure. If the 2 microphones are at equal distance from the source then the 2 traces are in phase. Move one microphone by half a wavelength and the 2 traces are opposite phase.

This experiment is best with a XO-1.5 or higher with stereo input. If you only have a mono XO-1 then you could parallel the 2 microphones to the mono input and see how the amplitude of the summed signal changes as you move one microphone

===Gliding tone===

@@ Line 11: / Line 11: @@
 Standard 3.5mm 2-pin switched mono microphone jack; selectable 2V DC bias; selectable sensor-input mode (DC or AC coupled); selectable +20dB boost.
-On the XO-1, mono data is measured, the left channel, the tip (usually the red wire). The XO-1.5 and the XO-1.75 can read both the left and right channel.
+On the XO-1, mono data is measured, the left channel, the tip (usually the red wire). The XO-1.5, XO-1.75, XO-3 and XO-4 can read both the left and right channel. (Currently on the XO-1.75, XO-3 and XO-4 stereo input is disabled).
-The XO-1 is protected at the input by a 5V zener diode. The allowable input is -0.5V to 5V. Inputs outside this range will cause excessive current and damage. Even a single 1.5V battery can cause damage if connected reverse polarity.
+The XO-1 is protected at the input by a 5V zener diode. ([http://wiki.laptop.org/go/File:XO-1_Schematics.pdf 1]) The allowable input is -0.5V to 5V. Inputs outside this range will cause excessive current and damage. Even a single 1.5V battery can cause damage if connected reverse polarity.
-The XO-1.5 is protected by a resistor,(1/16W 470 ohm SMD0402) and a pair of diodes to ground and to +3.3V which should protect -6V to +9V continuously, and up to higher voltages for shorter periods of time.
+The XO-1.5 ( [http://wiki.laptop.org/go/File:XO-1.5_Schematics_rev_G.pdf 2] [http://wiki.laptop.org/go/File:XO-1.5_Schematics_rev_I.pdf 3] [http://wiki.laptop.org/go/File:XO-1.5_Schematics_rev_M.pdf 4] )and XO-1.75 (XO-3 and XO-4 presumably too) are protected by a resistor,(1/16W 470 ohm SMD0402) and a pair of diodes to ground and to +3.3V which should protect -6V to +9V continuously, and up to higher voltages for shorter periods of time.
-The XO-1.75 also has the 470 ohms series resistor to the 2 diodes. If the resistor has the same wattage then the limits are the same.
 For the XO-1, the addition of a 150k ohm series resistor would (I expect, no guarantee) give a reduced sensitivity in voltage mode (0-4V) but allow inputs to +- 100V without damage. Input impedance in resistance, volume and pitch modes is much lower but a 1k ohm series resistor should still allow inputs to +-12V.
@@ Line 27: / Line 25: @@
 <i> 680 ohm series resistor on a 3.5mm audio plug</i>
-Test leads with a zener diode and series resistor would expand the safe range for the XO1.5 and XO1.75.
+Test leads with a zener diode and series resistor would expand the safe range for the XO1.5, XO1.75, XO-3 and XO-4.
 Damage can also be caused by applying voltages between the grounds of any of the external sockets.
@@ Line 41: / Line 39: @@
 ===XO-1.75===
-Two channels
+Two channels, -0.3V to 3V, input impedance 4k ohms to a 3V bias, (models SKU204+ *) . At the time of writing, as a workaround to a bug with dual channels, apply the input to both channels, only a mono reading is available.
--3V to +3V, input impedance 1k ohm to a +3V bias, model SKU199
+(* A small number of pre-production laptops were built with -3V to +3V input range and input impedance 1k ohm to a +3V bias, eg. model SKU199. Turtle Blocks V141 and previous is correctly calibrated for these laptops but not for production laptops)
--0.3V to 3V, imput impedance 4k ohms to a 3V bias, models SKU204+ to be confirmed
+===XO-4===
+Two channels, 0 to 3V. At the time of writing, as a workaround to a bug with dual channels, apply the input to both channels, only a mono reading is available.
 ==Resistance Mode==
@@ Line 55: / Line 54: @@
 ===XO-1.75===
-zero ohms to open circuit
+Two channels, zero ohms to open circuit. At the time of writing, as a workaround to a bug with dual channels, apply the input to both channels, only a mono reading is available.
+===XO-4===
+Two channels, zero ohms to open circuit. At the time of writing, as a workaround to a bug with dual channels, apply the input to both channels, only a mono reading is available.
 ==Pitch Mode==
@@ Line 432: / Line 434: @@
 == RC time constant ==
-IT IS RECOMMENDED THAT A SERIES PROTECTION RESISTOR BE BUILT INTO THE PHONO PLUG AND LEADS IF USING AN EXTERNAL VOLTAGE
+IT IS RECOMMENDED THAT A SERIES PROTECTION RESISTOR BE BUILT INTO THE PHONO PLUG AND LEADS IF USING AN EXTERNAL VOLTAGE WITH THE XO-1
 [[File:Rc cct.jpg]]
@@ Line 455: / Line 457: @@
   R = T/C
   = 0.14 /(4x10^-6) = 35k
 [[File:Rc-time.jpg]]
@@ Line 466: / Line 469: @@
 [[File:RC data to clip.jpg]]
+See also a similar experiment which uses the [[Activities/TurtleBots#Buti.C3.A1|USB4Butia]] board (in Spanish) http://youtu.be/eewFtOHX5-Q and http://youtu.be/KmNwC1qBhtA
+==Voltage-current relationship==
+Some devices including light bulbs have non-linear voltage current relationships. In this experiment, the V-I graph of a light bulb is drawn using the stereo input of the XO-1.5.
+[[Image:VIgraph.jpg|250px]]  [[Image:VI Turtle Art.png|400px]]
+[[File:Turtle Art Activity VI.ta]]
+The light bulb and resistor were chosen thus. The maximum measurable input of the XO-1.5 is +3V, at maximum you want approximately 1.5V across the resistor and 1.5V across the bulb, the bulb should be near full brightness. A 2.8V 0.85A torch/flashlight bulb was used. The estimated resistance of the bulb is V/I, 2.8V/0.85A = 3.3 ohms, chosing from resistors at hand, trial and error found 2.2 ohms was OK. The power rating of the resistor is V*V/R, 1.5*1.5/2.2 = 1.02W, a resistor of 1W or higher rating is required.
+A laboratory power supply was used in this experiment. It is safest if its output is within the maximum allowable voltage range of the XO-1.5, -6 to +9V. Low cost options would include a selection of dry cells in varying states of discharge. It may be practical to construct a variable resistor using a pencil lead.
+The X axis is voltage across the bulb, voltage2 - voltage, the Y axis is the current which is proportional to the voltage across the resistor or the L channel voltage.
+See also http://youtu.be/37vJEUr5nRI and http://www.youtube.com/watch?v=_iSXHsGvLaY (in Spanish) for experiments plotting linear and nonlinear V-I relationships using the [[Activities/TurtleBots#Buti.C3.A1|USB4Butia]] board.
 ==The XO as an audio amplifier==
@@ Line 522: / Line 543: @@
 http://www.youtube.com/embed/l3vKVTW1LQA
+One laptop running Turtleart is used to generate a 3kHz audio tone. The second laptop, XO-1.5 or higher, graphs the output of 2 microphones with Measure. If the 2 microphones are at equal distance from the source then the 2 traces are in phase. Move one microphone by half a wavelength and the 2 traces are opposite phase.
+This experiment is best with a XO-1.5 or higher with stereo input. If you only have a mono XO-1 then you could parallel the 2 microphones to the mono input and see how the amplitude of the summed signal changes as you move one microphone
 ===Gliding tone===