Electronics and sensors
E-Textile
Fabricademy 2023
Emma Pareschi
Program
Basic of electronics (current-voltage-resistance: Ohm's law) and basic circuit
Use of the multimeter to characterise each element of the circuit
Sensors: digital and analog
How to test the sensors without Arduino
The standard elements of interactive project.
Input
device
Output
device
Power
Collect data
Change the space
The standard elements of an interactive project.
Input
device
Output
device
Power
Microcontroller
Collect data
Change the space
Process and control
BASICS OF ELECTRONICS
“Among those who eat and those who are eaten nothing is created and nothing is destroyed but everything is transformed..”
Antoine-Laurent de Lavoisier. Father of modern chemistry
Any kind of interaction is a transformation/exchange...of energy.
ELECTRIC ENERGY.
Electric energy
A form of energy resulting from the existence of charged particles
Particles:
electrons - negative charge
neutrons - no charge
protons - positive charge
e-
e-
p+
p+
e-
p+
reject
attract
Electrical energy
p+
n
p+
n
e-
e-
p+
n
p+
n
e-
p+
n
p+
n
e-
e-
e-
NO charged
POSITIVELY charged
NEGATIVELY charged
Electricity
Electricity is the presence and use of electric energy.
Static
Dynamic
Dynamic electricity
p+
e-
p+
e-
p+
e-
Dynamic electricity
p+
e-
p+
e-
p+
e-
p+
e-
p+
e-
p+
e-
Dynamic electricity
p+
e-
p+
e-
p+
e-
p+
e-
p+
e-
p+
e-
p+
p+
p+
e-
e-
Dynamic electricity
also known as ELECTRIC CURRENT.
Current = flow of electric charges (electronics).
Unit of measure: Amperes (A) (“Amps”).
1A = 6241000000000000000 electrons
Most probably you won’t work with Amperes
but with lower amount.
Ex. LED: 0,005 / 0,020 Ampere
Annotation note:
1 milliAmpere (mA) = 0,001A
5mA = 0,005A
20mA = 0,020A
350mA = 0,350A
0,005 A - 0,02A
0,350 A
0,200 A
0,100 A
8 A
16 A
Dynamic electricity
p+
e-
p+
e-
p+
e-
p+
e-
p+
e-
p+
e-
p+
p+
p+
e-
e-
Why the electrons should move?
Dynamic electricity
p+
e-
p+
e-
p+
e-
p+
e-
p+
e-
p+
e-
p+
p+
p+
e-
e-
Positively charged
Negatively charged.
Source of electrons.
The power source causes the movement of the electrons (current).
Dynamic electricity
p+
e-
p+
e-
p+
e-
p+
e-
p+
e-
p+
e-
p+
p+
p+
e-
e-
The power source causes the movement of the electrons (current).
Power source - Voltage
+ + + + + +
Positively charged
+ + + + + +
- - - - - -
Negatively charged
- - - - - -
Positive
terminal
+
VCC
Negative
terminal
-
GND
The power source has always two terminals.
It has an orientation!!
The capability to move the charges between two points is called VOLTAGE.
Unit of measure: Volt (V).
Schematic representation.
9V
3.7V
1.5V
3V
Power source - How to measure it
Power source - Voltage
Can you measure the Voltage between two points? Yes.
Your best friend in the electronic lab is THE MULTIMETER
Black lead => port COM
Red lead => port V
To measure the voltage of a battery.�- select the right mode and range�- check if the the lead are in the right position�- touch the terminals of the battery with the two leads
Power source - Voltage
Positive number
Negative number
Circuit
A circuit is a system in which we use electric energy.
A circuit is a CLOSE LOOP in which electrons can travel in.
Circuit
A circuit is a system in which we use electric energy.
A circuit is a CLOSE LOOP in which electrons can travel in.
What do you need:�- source of electrons: POWER SOURCE�- material to let the electrons flow: TRACES
Battery
Wire
Circuit
A circuit is a system in which we use electric energy.
A circuit is a CLOSE LOOP in which electrons can travel in.
What do you need:�- source of electrons: POWER SOURCE�- material to let the electrons flow: TRACES
Battery
Wire
SHORT CIRCUIT
Circuit
A circuit is a system in which we use electric energy.
A circuit is a CLOSE LOOP in which electrons can travel in.
What do you need:
Battery
Wire
Resistor
Circuit - Power Source
5V
Circuit - Traces
The traces are physical media that lets the electrons to flow in.
How do I know if a material is conductive? MULTIMETER in Continuity Mode.
Circuit - Load - Resistor
A resistor is one of the most fundamental components in electronics. Its purpose is to impede a flow of current and impose a voltage reduction.
Two wires or conductors attached at opposite ends or sides of a relatively poor electrical conductor.
It has two sides, it doesn’t matter the orientation.
The resistance of resistor is measured in Ohms, universally represented by the Greek omega symbol, Ω.
Circuit - Load - Resistor
The simplest circuit
what is the relation between
Voltage - Current - Resistance?
OHM’S LAW
Ohm’s Law defines the relation between voltage, current and resistor:
V = I * R = IR
Higher is the Resistor => Lower is the current
Lower is the Resistor => higher is the Current
You know the Voltage and the Resistor =>
=> calculate the current you consume —>
You know the Voltage and the Current =>
=> calculate the resistor you need —>
I = V / R
R = V / I
OHM’S LAW
Circuit
The simplest and most useless circuit: there is current but the energy is not used.
(it is useless unless you use the resistor as heating element)
Let’s use the electric energy to generate light.
Led
Light Emitting Diode
long +
short -
+
-
Anode (+)
Cathode (-)
Vf = 2V / 3V
If = 0,005A / 0,02A
Vf = 3V
If = 0,300 A
Led circuit
Led circuit
Led circuit
Led circuit
?
Led circuit
R = (Vcc - Vf) / If
R = (9V - 2V) / 0,02 A = 350 Ohm
Voltage across a circuit
350 Ohm
Vr = 7V
Led calculations
Circuit with Led
If we use a 3V battery
long
+
short
-
Circuit with Led and resistor
If we use a 9V battery
Led circuit
Led circuit
Led circuit
FABRIC
TRACES
*Fused with Heat’n’bond. See appendix
A
B
C
D
E
F
THREAD
TRACES
A
B
C
D
E
F
G
PERMANENT
SOLDER + SEW
Solder if you can and ALWAYS cover knots and joints with fabric or hot glue.
PERMANENT
SOLDERING SMD
Place a bit of solder onto the thread or fabric and back of component first, then solder them together. Use flux and tweezers to make your life easier - it takes some getting used to.
Solder if you can and ALWAYS cover knots and joints with fabric or hot glue.
PERMANENT
SOLDER + SEW + CRIMP
A
B
C
D
E
It is a good result, but what about interaction?
Circuit that interacts - Sensors
A circuit is a system in which we use electric energy.
A circuit is a CLOSE LOOP in which electrons can travel in.
What do you need:
Battery
Wire
Light
Sensor
Sensors
We use sensors because the interaction with them generates an electric signal: a change of Voltage.
Digital vs Analog
Circuit that interacts - digital
A circuit is a system in which we use electric energy.
A circuit is a CLOSE LOOP in which electrons can travel in.
What do you need:
Battery
Wire
Light
Digital sensor
Digital Sensor
Digital sensors are devices that have only two possible status:
ON or OFF
They OPEN or CLOSE
They have two terminals that can be connected or not.
Example: the push button or stroke sensor
Digital Sensor
Two conductive parts that can mechanically touch each other. When they touch each other, we say that the switch is close, otherwise it is open.
Momentary switch
Digital Sensor
Momentary switch
Digital Sensor
Momentary switch
Digital sensor - how to test it
Digital sensor - the circuit
Digital sensor - the circuit - how to test it
Circuit that interacts - analog
A circuit is a system in which we use electric energy.
A circuit is a CLOSE LOOP in which electrons can travel in.
What do you need:
Battery
Wires
Light/Motor
Analog sensor
Analog Sensor
Analog sensors are VARIABLE RESISTORS.
Interacting with the sensor,
you change the resistance,
so you change the current.
They have two terminals.
Example: pressure sensor, stretch sensor
Material
Analog Sensor
Velostat is a piezoresistive material, meaning it’s electrical resistance decreases when pressured.
When sandwiched between two conductive layers, it has a wonderful range for making pressure and bend sensors.
Analog Sensor
Analog Sensor
Analog Sensor
Analog Sensor - how to test it
Analog Sensor - the circuit
Analog Sensor - the circuit - how to test it
Examples
Examples
Modular system
Modular system
Power Module
Input Module
Output Module
End Module
Full system
Power source
Sensor
Digital or Analog
Output device
Trace
Traces
Traces
Connection
Connection
Beautiful examples
Beautiful examples