Outputs Devices

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individual assignment:
    add an output device to a microcontroller board you've designed,
         and program it to do something
    
    

FAN's

I'd sow that I'd some out-of-use Fans in my homeLab:

Knowing the Voltage and Current needed to make them work:

used the ISO-TECH Laboratory DC Power Supply IPS 303DD

Connected the GND and VCC

V=3 and A=0,11.. made it work...

Conclusion:
• For a LOW wind: V=3,5 A=0,11A
• For a HIGH wind: V=5 A=0,26A

Board design

I would need to create a mean to use them in the Fungarium to make air circulate... so

Will need:
• microcontroller to send 3 signals: OFF, LOW and HIGHT

some research... starting at FabAcademy - "inputs fan"

I found some students output assigments with fan

• Florian Paproth Used the PWM on a Atmega328, its fan needed 12V and had four cable for speed control and for telling its rotation per minute.... He decided to control the speed with the PWM signal, since its a technique to change a signal from high to low on a specific frequency.
• Anna Waldman-Brown who thought on using H-bridge + Attiny44 but then, due to H-Brodge complexity, decided on a Solid State Relay..

Studing Atmega328P

Atmega328P Speed

One of the main issues is the Microcontroller speed and acuracy needed to control the outputs

found inspiring page About Circuits, which I'll quote:

By default Atmega328P will work at 1 Mhz, because Fuse Bit Low default value is 0, so the value presented in Table 8-10, note 2, of 8 Mhz will be devied by 8, resulting in 1 Mhz.

!!! Set it to work at 16 Mhz.

Need to work on the Hardware and Software.

Hardware: Add a Crystal Oscillator:

 
            16 Mhz crystal
            two 22pF ceramic capacitors
            connected to XTAL1 as input pin
                    and XTAL2 as output pin
    

Here it's

Eagle 9.3.0 does not recognize FAB.LBR...

so I installed an oler version, Eagle 7.7. for MAC 64bts just to add the components, if you need here is the Zip file to install the EAGLE 7.7 MAC 64bits

Software: Change the Fuse Low Byte settings

 
            - only the Fuse Low Byte needs to be changed
            Considerations around the Fuse Low Byte:
                - bit 7 needs to be changed from 0 to 1
                - bit 6 can be left set to 1
                - Bits 5 and 4 control the startup time - set to 1 1
                - Bits 3-0 control the oscillator choice - 1 1 1
    

Atmega328P Power

I will need to conect a external power supply, so found this one on my stuff:

adding the components in eagle 77

wiring in EAGLE 9.3.0

OutPut's connections

I'll need to use PWM to both Outputs

I'll connect a Pair of Colums and a pair os fans, each using 2 pin-headers

Even knowing that there's a missing link between all the GND's I'd cutted it on Milling Machine

I'm assuming a risk....that not all the Atmega328P GND pins are collectively connected.... But a read online that this could work even so....

Correction: my Fab Guro advised me to use a 0ohm resitor to connect the grounds lefting in last design... and here is the new Eagle Board Design, you can Download Schematic and Board

Soldering all the parts.... 4 capacitors in a row :)

There was no 22pF capacitor on the lab, so I'd to join 4 to have this capacity: 10pF + 10pF + 1pF +1pF

and after soldering here it is...

There was no 22pF capacitor on the lab, so I'd to join 4 to have this capacity: 10pF + 10pF + 1pF +1pF

Atmega328 P Datasheet:

• Six PWM Channels
• Which Are:
  1. MOSI/OC2A/PCINT3 – Port B, Bit 3 - The OC2A pin is also the output pin for the PWM mode timer function.
  2. SS/OC1B/PCINT2 – Port B, Bit 2 - The OC1B pin is also the output pin for the PWM mode timer function.
  3. OC1A/PCINT1 – Port B, Bit 1 - he OC1A pin is also the output pin for the PWM mode timer function.
  4. AIN0/OC0A/PCINT22 – Port D, Bit 6 - The OC0A pin is also the output pin for the PWM mode timer function.
  5. T1/OC0B/PCINT21 – Port D, Bit 5 - The OC0B pin is also the output pin for the PWM mode timer function.
  6. INT1/OC2B/PCINT19 – Port D, Bit 3 - The OC2B pin is also the output pin for the PWM mode timer function.
• 19.7.3 Fast PWM Mode - The Fast Pulse Width Modulation or Fast PWM modes provide a high frequency PWM waveform generation option. The Fast PWM modes differ from the other PWM options by their single-slope opearation... The counter counts from BOTTOM to TOP, then restarts from BOTTOM. ... Due to the single-slope operation, the operating frequency of the Fast PWM mode can be twice as high as the phase correct PWM modes, which use dual-slope operation. This high frequency makes the Fast PWM mode well suited for power regulation, rectification, and DAC applications. High frequency allows physically small sized external components (coils, capacitors), and therefore reduces total system cost.