Output Devices

ASSIGNMENT

Measure something: add a sensor to a microcontroller board that you have designed and read it

As OUTPUT DEVICES I have programmed a LedRing, the same LedRing that I will later need in my FinalProject (neopixel x12)

BACK

FRONT

First of all, however, I drew my board on EAGLE.

SCHEMATIC

BOARD

Once the board has been designed, I mill it with the Roland MDX-40

TOP

TOP & OUTPUT

Having milled my board, I start drilling the holes where I need them (where I will solder the cables) and then I go on to solder the electronic components I need:
- RES
- CONDENSER
- ATTINY_44 SUPPORT
- EXTERNAL PINS

ELECTRONIC ELEMENTS I NEED

Once my card is completed I have to program my attiny_44

PROGRAMMING

PROGRAM

For the programme, I decided to have my LedRing change colour every "some" time

Once the Attiny_44 is programmed, I solder my cables to the board and connect the battery (I put two in series) and a button that will be used to switch the LedRing ON and OFF to the 2 external pins.

HOW COME I PUT THE BATTERIES IN SERIES?

I put the batteries in series because each of them "gave off" 3.3v but I needed at least 5v, so one battery was too little, so I put them in series being careful not to exceed the maximum value of volts supported.

HOW DO YOU PUT BATTERIES IN SERIES?

I connected the red cable of one battery with the black cable of the other battery, so I was left with a black cable from one battery and a red cable from the other battery. I then crimped these two exposed cables and attached a female connector to them, which I then attached to the male connector soldered to my board.

To see what my LEDRING will be used for go to FinalProject_4

HOW I PROGRAMMED THE ATTINY_44

To program the ATTINY_44 THROUGH HOLE I connected it to a break board, from there I used the pinout file to understand which connections corresponded to that pin (GND-VCC-SCK) and through a jumper I connected it to the Arduino Uno to be able to program it and I connected the wires connected to the LedRing (GND-VCC-SCK) so I could see if the code worked or not. To do this, however, I also need a capacitor (between VCC and GND) and a 330ohm resistor (between the MOSI pin of the Attitiny_44 and the SCK pin of the LedRing). Before loading the code, however, I must first set up the IDE connections:
- BOARD: ATtiny24/44/84(a) (No Bootloader);
- CHIP: ATtiny44(a);
- CLOCK: 8 Mhz (internal);
- B.O.D. LEVEL: B.O.D. Disabled (saves power);
- SAVE EEPROM: EEPROM retained;
- PIN MAPPING: Clockwise;
- LTO: Enabled;
- TINY NEOPIXEL PORT: Port A;
- MILLS: Enabled;
- PORT: USB of the Arduino (unique number);
- PROGRAMMER: USBtinyISP;
To upload the code to the Arduino I need the Adafruit library which is the library from the parent company dedicated to my LedRing.

FILE

- LED RING CODE
- SCHEMATIC
- BOARD

Group assignment¶

- This week we were to calculate\measure the power consumption of one of our outputs.

- We decided to measure the power spent by my LED matrixes.

- At their maximum brightness, Neopixels should draw up to 60 milliamps, but generally they are never turned up that way.

- Adafruit gives the following function to estimated the absolute maximum of minimum amps needed (at 60mA) and a generally acceptable value (at 20mA).

- number of NeoPixels * 20 mA ÷ 1,000 = x Amps minimum number of NeoPixels * 60 mA ÷ 1,000 = x Amps minimum

- Therefore, in my case these values would be:

- 256 * 20 mA ÷ 1,000 = 5.12 Amps minimum 256 * 60 mA ÷ 1,000 = 15.36 Amps minimum

- By datasheet each 8x8 Neomatrix has a maximum power consumption of (W): 0.24W x 64 = 15.36W, so that would be for all four (W): 0.24W x 256 = 61.44W.

- The formula to calculate power consumption is W(atts) = V(olts) × A(mpere); it can also be displayed as power consumption per hour, being Wh = W(atts) x h(our).

- Now, these were all estimates: it is time for me to check physically, using a voltimetre and a bench power supply.