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Minor fixes to guitar demo

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Richard Knoll
2016-10-03 16:37:13 -07:00
parent 5e9eec61c5
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docs/projects/guitar/lightsensor.md
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@ -4,7 +4,7 @@
### ~avatar avatar
Use the Light Sensor to the control tone for this [Theremin](https://en.wikipedia.org/wiki/Theremin) inspired guitar
Use the Light Sensor to the control tone for this [Theremin](https://en.wikipedia.org/wiki/Theremin) inspired guitar
* **Concepts:**
* Inputs
@ -12,19 +12,19 @@ Use the Light Sensor to the control tone for this [Theremin](https://en.wikiped
* Tone/Frequency
* Ratio Mapping
* Forever Loop
* Math (multiplication) with code properties
### ~
* Math (multiplication) with code properties
### ~
## Duration: 30 - 45 minutes
*playing tones with light sensor*
## Duration: 30 - 45 minutes
*playing tones with light sensor*
https://youtu.be/2cKg9pokVC4
## The micro:bit LEDs Light Sensors
## The micro:bit LEDs Light Sensors
- the micro:bit can detect external light level intensity reaching the LEDs
- the micro:bit can detect external light level intensity reaching the LEDs
- the light level block reports a reading of values 0 (*dark*) to 255 (*bright*)
- a **Forever Loop** is required to continually use measure the current light level to control the tone
- a **Forever Loop** is required to continually measure the current light level and control the tone
## Forever Loop
@ -46,70 +46,70 @@ basic.forever(() => {
})
```
**Build the blocks**
* From **Basic** drag a **forever loop** block into the coding area
* From **Led** drag a **plot bar graph** block into the **forever loop**
* From **Input** drag a **light level** block into **plot bar graph *of***
**Set the *plot bar graph* value *up to* = *255* **
* From **Basic** drag a **forever loop** block into the coding area
* From **Led** drag a **plot bar graph** block into the **forever loop**
* From **Input** drag a **light level** block into **plot bar graph *of***
## Step 2: Test the light required to move the bar graph height
**Set the *plot bar graph* value *up to* = *255* **
*graphing light input*
https://youtu.be/pqU7bTcfQ_s
Experiment to see the effect on graph height when the **plot bar graph** value ***up to*** is changed
## Step 2: Test the light required to move the bar graph height
**255 is the maximum light input reading**, try numbers smaller than 255
**Find a value** that allows the graph to show 1 - 5 bars
*graphing light input*
https://youtu.be/pqU7bTcfQ_s
Experiment to see the effect on graph height when the **plot bar graph** value ***up to*** is changed
**255 is the maximum light input reading**, try numbers smaller than 255
**Find a value** that allows the graph to show 1 - 5 bars
### ~hint
### Frequency
**Frequency** measured in Hz which are cycles per second or vibrations per second
* A healthy human ear can detect frequencies in the range of 20Hz to 20,000Hz.
* The micro:bit + headphones reliably produce detectable output ~50Hz - 6,000Hz.
### Frequency
**Frequency** measured in Hz which are cycles per second or vibrations per second
* A healthy human ear can detect frequencies in the range of 20Hz to 20,000Hz.
* The micro:bit + headphones reliably produce detectable output ~50Hz - 6,000Hz.
**261Hz** represents a C note
```blocks
music.playTone(261, music.beat(BeatFraction.Half))
```
**play tone** blocks can specify a specific numeric **Frequency**
by replacing the letter note 261Hz represents a **C** note with a **number** block
**play tone** blocks can specify a numeric **Frequency**
by replacing the letter **C** note with a **number** block that has the value it represents
```blocks
music.playTone(261, music.beat(BeatFraction.Half))
```
### ~
### ~
## Step 3: Multiply Frequency using Math blocks
```blocks
input.onButtonPressed(Button.A, () => {
music.playTone(261 * 2, music.beat(BeatFraction.Half))
})
```
create a **play tone** block using a **Math** section, **multiplication** block to set *tone*
```
Create a **play tone** block using a **Math** section, **multiplication** block to set *tone*
### Next
**Add** a **B** button block that multiplies the **261** tone by a number other than 2 to set tone
**Download the code to the micro:bit**
### Next
**Add** a **B** button block that multiplies the **261** tone by a number other than 2 to set tone
**Download the code to the micro:bit**
**Test the sound for multiples of the 261Hz *C* frequency**
**Test the sound for multiples of the 261Hz *C* frequency**
## Step 4: Control the Frequency with the light input
```blocks
basic.forever(() => {
music.playTone(input.lightLevel() * 25, music.beat(BeatFraction.Quarter))
})
```
**Create a *forever loop* containing a *play tone* block**
**Set *tone*, using *Math* multiplication block that multiplies *light level* input by 25**
or experiment with multipliers larger and smaller than 25
**Test light tone control on the guitar**
Cover the LEDs with your hand to vary light detected to control the tone
**Create a *forever loop* containing a *play tone* block**
**Set *tone*, using *Math* multiplication block that multiplies *light level* input by 25**
or experiment with multipliers larger and smaller than 25
**Test light tone control on the guitar**
Cover the LEDs with your hand to vary light detected to control the tone
## Good work, this guitar is sounding good!
**Challenge:** Create a variable for the light level multiplier that you can change using buttons (optional)
**Challenge:** Create a variable for the light level multiplier that you can change using buttons (optional)
### ~button /projects/guitar/accelerometer
NEXT: Accelerometer Beat control
### ~button /projects/guitar/accelerometer
NEXT: Accelerometer Beat control
### ~