# Week 9
## Output Devices
### Group Assignment
> Measure the power consumption of an output device
We measured the power consumption of a small electric motor using the oscilator. You can see that this 9v electric motor hovers around a constant voltage when it is running with almost no resistiance. However, when we prevented it from spinning, the motor consumes more electricty.
|  |  |  |
|:---------:|:---------:|:---------:|
| *The motor consumes a steady voltage as shown on right half of osciloscope screen* | *Preventing the motor from spining will cause the motor to draw more current* | *Zooming in closer on current on the osciloscope to see the variation in the current* |
We also saw how much power these LEDs can handle before the break, and the difference between wiring in series vrs. in parallel
|  |  |
|:---------:|:---------:|
| *Increasing voltage until LEDs turn off or explode* | *An exploded LED with a cracked plastic top* |
### Individual Assignment
> Add an output device to a microcontroller board you've designed,
and program it to do something
#### DFPlayer module
I want to use this [DFR0299 DFPlayer Mini MP3 Player module](https://www.dfrobot.com/product-1121.html).
I started by looking at the example files:
- [hello.DFR0299.RP2040.kicad_pro](http://academy.cba.mit.edu/classes/output_devices/MP3/hello.DFR0299.RP2040.kicad_pro) This file contains general program information. You should click on this file to open up the project.
|  |
|:---------:|
| *File structure of kicad files showing how _pro, _pcb and _sch file types are used* |
- [hello.DFR0299.RP2040.kicad_sch](http://academy.cba.mit.edu/classes/output_devices/MP3/hello.DFR0299.RP2040.kicad_sch) You need this file because it contains the information for the KiCad Schematic Editor
- [hello.DFR0299.RP2040.kicad_pcb](http://academy.cba.mit.edu/classes/output_devices/MP3/hello.DFR0299.RP2040.kicad_pcb) You also need this file because it contains the information for the KiCad PCB Editor
- Images of the schematic and the PCB
|  |
|:---------:|
| *Schematic and PCB (where the traces will be cut) for XIAO RP2040 and DFR0299* |
I modified this example to create a pad:
|  |  |  |
|:---------:|
| *The copper traces of the mp3 Pad* | *The copper traces of the mp3 Pad* | *The edge cuts of the mp3 Pad* |
## Attachments
[mp3-player-copper.png](images/251030-mp3-player-copper.png)
[mp3-player-drill-holes.png](images/251031-Mp3-Player-Drill-Holes.png)
[mp3-player-edge-cuts.png](images/251031-Mp3-Player-Edge-Cuts.png)
## Acknowledgments