7. Electronics design¶

This week I worked on defining my final project idea and started to getting used to the documentation process.

Files to download¶

BOR Schematic & Board design download + rml

Research¶

R1 = Resistor C1 = Capacitor VCC = voltage (+ve black) GND = Ground (-ve red)

Useful links¶

Basics¶

Ohm’s Law = 1-Voltage (V)(as if pressure) 2-Currrent (I) 3-Resistor (R) V= I * R

IC1= Microprocessor

Kind reminder The positive leg of the LED called Anode - usually have a longer leg
(and is wired to power) sensor

The Negative leg of the LED called Cathode - usually have a shorter leg
(connects to ground) sensor

Group Project¶

Using the digital multimeter to check the continuity between ground pins and VCC pins. Also, we measured the VCC to GND voltage, which should be 5V.

GND (Ground) Continuity- We measured the continuity between the GND pins of the ATtiny44, SPI header and FTDI header. The digital multimeter should beep and read around 0 Ohm. This means all the three pins are connected. group

VCC (5V) Continuity- We measured the continuity between the VCC pins of the ATtiny44, SPI header and FTDI header. The digital multimeter should beep and read around 0 Ohm. This means all the three pins are connected. group

VCC-GND Continuity- We measured the continuity between the VCC pin and GND pin. The digital multimeter should not beep and read OL (Overload). This means there is no connection (short circuit) between the VCC and GND. group

VCC to GND Voltage¶ We connected the board to the FabTiny programmer and then to USB. We measured the voltage between the VCC pin and GND pin. The digital multimeter read 5V, which is the USB port voltage. group

Individual Assignments¶

KiCad¶

Download - KiCad

resonator and capacitor make them close to their connections

layer on the right side (like layers on Autocad) F.Silks check and uncheck to display the name or hide them (making it easier to see)

Design rules -Width (thickness of the line/traces if too thin might rup off while cutting) -Clearance (offset how much it removes from copper - the minimum would be the size of bit/milling if this distance was less than diameter of the bit then game over it won’t see it or cut it and cooper would remain there between 2 traces as if it’s one line or trace )

F.Cu
Ege.Cuts the only 2 layers i need to keep before exporting

then open on photoshop open with a high resolution 500 then export PNG or SVG (takes both)

then for interior you make everything white export SVG file

Multi meter my new best friend during electronics

Eagle¶

Step 1 download Eagle - Eagle

Step 2 Download the PNG of the board to follow - ATtiny44 Board

Step 3 download LBR/ BRU (in schematic) in library update (to add it)

Step 4 Right click on your project and select “New > Schematic”. This will add a schematic to your project and open the “Schematic Editor”. (in schematic) Add components- originals * add to schematic the components of the original echo hello-world board. Click on “Add Part” and in search field look for “tiny“. Double click on “UC_ATTINY44” under fab library. Select “UC_ATTINY44 - SOIC14” and click “OK”. repeat for all these basic components in the table below * you can connect visually by line or simply label9 and rename then they would connect automatically and it would ask you with a popup menu if you wanna connect and you put yes)

Step 5 (in schematic) Add LED +Res.+switch + Bottom as in table below. schematic should look similar to the image below. You can arrange components in schematic as your preference. name and value

step 6 change value of Resistor name and value

step 7 Change name and value of Resonator

step 8 Add VCC and GND - make each connection needed to them as the diagram

Step 9 Go to board and connect components name and value

Step 10 Draw outline with 32 thickness (anything higher than traces) of the line name and value

step 11 In order to export the traces and interiors as png files, so we can use in mods to generate the rml files for the milling machine. Go to “Layer Settings” and hide all layers by clicking on the eye icon, only keep “1 Top” and “20 Dimension”. Click “OK”. name and value

Step 12 Export Image(Resolution 500) - monochromic and please give your file a name! export

Step 13 the exported image should look something like this export

Step 14 open photoshop to export traces PNG export

Step 15 Also used photoshop to export outline PNG export

step 16 Using mods upload the traces PNG

mods mods remeber to put al axis 0 mods Saving the PNG mods repeat for outline AKA. interior mods but i have discovered i forgot to change resolution once i uploaded as well as image size exported from photoshop changed compared to the exported image from eagle (so instead of width being almost 4 cmm became 29 cm )so i re-did all the above eagle traces outline mods mods Plug in the save button to save …

Now moving to the machine after changing the milling bits, for traces 1/64” (0.4 mm), and for interiors 1/32” bit (0.8 mm).

Step17 setting you origins X/Y … then Z but then move the Z one mmm (just in case) machine machine machine machine

Step18 Take out the board you cut and take a cool video of that wink emoji board

Step 19 Gather components to start soldering

Step 20 For soldering I used the chart below exported from eagle after turning all layers “on” (from layer setgtikngs - Show layer) to follow up chart

Step 21

Hero Shoot!¶

components

Conclusion 0-Check with multimeter the board alone before soldering a)Micro processor b)ISP c)FTDI
1-Check with multimeter the connection between components after soldering same order as point 0 (one point with al the other points) 2- Kindly check the clearance as once export from eagle traces 16 , clearnance 16 isnt enough must be at least 18! to avoid such short circuts like what happened with me at first as you see in the circle where i scratched with a cutter. mistake

with multimeter better use oscilloscope

Programing

i uploaded the code using Arduino software after downloading few libraries for the windows check the embedded programming for more details … so after the computer recognized the ISP of the PCP i connected the ISP PCP to the ISP of my board then on Arduino software i recognized its appearing and was able to transfer the code

Code¶

Traces Code

// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin 12(transistor) as an output.
  pinMode(13, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(13, HIGH);   // turn the transistor  on (HIGH is the voltage level)
  delay(10000);                       // wait for 10 seconds
  digitalWrite(13, LOW);    // turn the transistor off by making the voltage LOW
  delay(10000);                       // wait for 10 second
}