dig:lab_4
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— | dig:lab_4 [2013/03/21 20:40] – [Instructions] tobi | ||
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+ | ===== Lab 4 ====== | ||
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+ | In [[lab_3]] we built a prototype of our microphone-servo board. Now let's design the schematic of our own PCB. We'll draw an Eagle schematic of the microphone amplifier and servo supply / connector from lab 3, using the PCB design tool Eagle. It is not a very super powerful tool but installs very quickly, comes in a freeware version with limited functionality, | ||
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+ | ** This is an individual exercise and each student must complete it on their own laptop. ** | ||
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+ | ==== Preparation (before lab exercise) ==== | ||
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+ | - See [[pcb]] for the links to download the freeware and limited version of Eagle. | ||
+ | - Download and unpack the {{dig: | ||
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+ | {{dig: | ||
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+ | ===== Instructions ===== | ||
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+ | In this exercise we'll draw an Eagle schematic of the microphone amplifier and servo supply / connector from [[lab_3]]: | ||
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+ | {{dig: | ||
+ | Remember that you actually modified some resistor values in lab_3 to bring the LM324 output more in the middle of it working range (see datasheet extract below). | ||
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+ | - Install Eagle - see [[pcb]]. | ||
+ | - Open the Eagle dashboard by launching Eagle. | ||
+ | - Open the copper board schematic. You should see something like this view: {{dig: | ||
+ | - Save it off to a new schematic called **mic-servo.sch**. | ||
+ | - Modify your schematic so that the DIL32 header is correct for the bronze board (since we have more of these boards we will use it as the motherboard). | ||
+ | - Add or use gates (symbols) for a resistor, polarized capacitor, LM324 opamp, microphone, and 3 pin header. | ||
+ | - Delete the unused symbols. | ||
+ | - Wire up the parts according to the sketch above. | ||
+ | - Ensure your designators and values are correct. | ||
+ | - Place a large label indicating the design name and designer name (your name). | ||
+ | ---- | ||
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+ | When you are finished with your board schematic, send your schematic file (.sch) to [[tobi@ini.phys.ethz.ch? | ||
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+ | === Eagle tips === | ||
+ | * Use a mouse. A middle click then lets you drag around your view. | ||
+ | * Eagle looks for designs in the directories that you specify in the //Control Panel//, under // | ||
+ | * Eagle uses a non-conventional way of manipulating objects that takes a bit of getting used to. You cannot drag-select objects for instance. Instead, you select a tool, say " | ||
+ | * Right click on objects to open the context menu. | ||
+ | * To select an object, look for the little cross in the object and click near that. | ||
+ | * Use the **Net** tool to draw connections between components, not the Wire tool. | ||
+ | * Many components have hidden power pins, e.g. the LM324. To show these pins so you can wire them up to your Vdd/Gnd, use the **Invoke** command on the part. Then you will see the hidden power pin ' | ||
+ | * The Cadsoft Eagle {{dig: | ||
+ | * This [[http:// | ||
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+ | === LM324 tip === | ||
+ | The input range of the LM234 is limited: | ||
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+ | {{dig: | ||
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+ | === Data sheets === | ||
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+ | * {{dig: | ||
+ | * {{dig: | ||
+ | * {{dig: | ||
+ | * Ultra capacitor, http:// | ||
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+ | ~~DISCUSSION~~ | ||
dig/lab_4.txt · Last modified: 2024/02/29 07:28 by 127.0.0.1