Line 1: |
Line 1: |
| <b>CAUTION. APPLYING EXTERNAL POWER SOURCES TO THE XO LAPTOP'S MICROPHONE INPUT CAN CAUSE PERMANENT DAMAGE. BE SURE YOU READ AND UNDERSTAND THE FOLLOWING BEFORE CONNECTING POWER SOURCES TO YOUR LAPTOP.</b> | | <b>CAUTION. APPLYING EXTERNAL POWER SOURCES TO THE XO LAPTOP'S MICROPHONE INPUT CAN CAUSE PERMANENT DAMAGE. BE SURE YOU READ AND UNDERSTAND THE FOLLOWING BEFORE CONNECTING POWER SOURCES TO YOUR LAPTOP.</b> |
| | | |
− | The OLPC XO can measure external inputs with its microphone jack
| + | ==Specifications== |
| | | |
− | ==Specifications==
| + | The OLPC XO can measure external inputs with its microphone jack. |
| | | |
| Standard 3.5mm 2-pin switched mono microphone jack; selectable 2V DC bias; selectable sensor-input mode (DC or AC coupled); selectable +20dB boost. | | Standard 3.5mm 2-pin switched mono microphone jack; selectable 2V DC bias; selectable sensor-input mode (DC or AC coupled); selectable +20dB boost. |
Line 11: |
Line 11: |
| It is protected at the input by a 5V zener diode and has a measurement range of 0.4V to 1.85V. The allowable input is -0.5V to 5V. Inputs outside this range will cause excessive current and damage. | | It is protected at the input by a 5V zener diode and has a measurement range of 0.4V to 1.85V. The allowable input is -0.5V to 5V. Inputs outside this range will cause excessive current and damage. |
| | | |
− | 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. If applying an external voltage, it is highly recommended that test leads be made up with a mictophone plug and a series resistor. | + | 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. If applying an external voltage, it is highly recommended that test leads be made up with a microphone plug and an inbuilt series resistor. |
| | | |
| ==Voltage Mode== | | ==Voltage Mode== |
Line 20: |
Line 20: |
| | | |
| ==Pitch Mode== | | ==Pitch Mode== |
− | Pitch Mode is set up for the internal microphone but can be accessed through the microphone jack. 2V DC bias is on, AC coupled, +20dB boost is on. The resolution is +-8Hz | + | Pitch Mode is set up for the internal microphone but can also be accessed through the microphone jack, 2V DC bias is on, AC coupled, +20dB boost is on. The resolution is +-8Hz |