Lecture Notes¶
Wednesday Neil¶
Ribbon cable - Use this instead of loose pins
Wire is specified by AWG
You can search AWG vs Current
Connectors
EDA (Electronic design automation)
How 2 pcb¶
First start sketching on paper
then create a schematic
then place components
then route wires
simulation?
fabrication
EDA¶
0 Ohm resistor to create bridges on one layer boards
DRC (Design rules check)
KiCad - One of the best pcb design softwares. Biggest limitation they are seperate programs
SnapMagic, To get footprints into kicad
schemtic -> pcb tool to lay out your schemtic physicaly
Fabrication toolkit for KiCad
Eagle is build into fusion.
https://componentsearchengine.com https://libary.io
Don't forgot an LED
Test equipment¶
Multimeter Osciliscoop Logic Analyser
Assignemnt¶
Group: Use test equipment to look a test equipment. Check voltage Check noise using Osciliscope Logic analyser to decode what its doing
Individual: Use a EDA tool to design a development board.
Extra: Simulate it. Extra: Design a case for it kicad
Thursday Erwin¶
Circuit - A circuit a closed loop where electrons can flow
Difference in electrical ptential between points sum of all coltages around a loop = 0; There is never loss in voltage Water analogy
Water definition High water fall high voltage The more water the more current
Wall sockets - AC - The polarity switches constantly DC- Always positive or negative
Tools¶
Multimeter¶
Test voltage, current, resistance Some can test capacitors.
Make sure to check where you wires are in.
Oscilloscope¶
Oscilloscope screen is a grid which each square having value. Each square can have ms in time and voltage.
make sure to connect the line you wanna test and the ground
3 Importand knobs on the oscilloscope
- Amount of volts to be displayed (change volt per square)
- 2 buttons for each channel to change the height on the screen of the signal
- Time to be displayed
Oscilloscope is used when you have a problem. When something isn't working and you don't know what.
voltage drop
always first connect the ground
You use Trigger to synchronize the oscilloscope to your signal
Logic analyzer¶
Can sense microcontroller communication and display it digitally on your laptop.
salaea logic (software)
Can only see digital signals. No analog ones
Logic analysers can translate protocol to human readible stuffs
KiCad¶
PCB creation connect components and design circuits
Schematic¶
Create seperate schematics and connect them using labels.
Use labels to keep it clean.
If you press A
you can see all components
Now we search resistor and select it.
Now there is a resistor! Now we can also add a LED the same way.
Key | What? |
---|---|
W | Draw wire |
A | New part |
E | Edit value (Only works on components that can be edited) |
X | Draw a trace |
D | Drag Move something with traces |
F | Finish the route for me |
Connector mounting pins
Make sure to add VCC and GND to your design even when you use pins to connect something
Now we can go and make the circuit board.
Pcb layout part¶
In here you will define the physical placement of the pcb.
You can do anything with pcb's and you can make them any shape you want.
Assigning footprints¶
When importing I got this error
This is because we didn't tell KiCad what type of components they are (SMD or through pins)
Tools -> assign footprints
After you've assigned it all it should look like this.
Custom shape¶
On the right you see a lot of layers.
Silkscreen - Text Solder mask - Prevent solder to stick to that mask EdgeCuts - Shape of the pcb F.Cu - Front copper
Design rules¶
The closest track space can be the size of the tool (0.4mm) Always should give traces some more spaces between each other because otherwise its going to be super hard to check it with a multimeter.
File -> Board setup -> design rules
In here yo can set design rules for the print.
These settings are based on the machine it is produced on.
For high power circuits you need to set bigger traces otherwise you have a higher resistance and the traces will get hot.
Don't forget to change the settings in
Net Classes
Exporting the board¶
File -> Export ->
Via - Circle through pcb
everything comes from digikey