Week10 lecture notes
3/25/2026 Output Devices
slightly newer TOF sensor VL53L5CX can do realtime 3D room mapping https://hackaday.com/2026/02/14/real-time-3d-room-mapping-with-esp32-vl53l5cx-sensor-and-imu/
Document as you go: https://www.youtube.com/watch?v=KSs416dsgvY
if anyone has i2c problems https://fabacademy.org/2022/labs/fct/students/ricardo-marques/assignments/week11-2/
https://foldscope.com/
For your biobreak: https://www.youtube.com/watch?v=s9jqQ-t-cm8 @Superfablab Kochi Kevin...the foldscope uses the Leeuwenhoek "ball" lens. Read about it here https://lensonleeuwenhoek.net/content/tiny-lenses
Lecture:
Safety: Outside body shock ~1 mA ok ~10mA shock, contracts muscles ~100mA fibrillation, stops heart for fibrillation it also needs to go through your heart Through fingers, not across heart hurts but I just short circuited the two pins so no harm
If shock inside body (needle inside body) even low V can be very harmful
V=IR so higher V and higher I are dangerous
Be very careful Clean work area Test circuit first
Power: Usb chargers are convenient PD fast charging test board 5-20V Modules that convert power supply MakerHawk voltage and current reader super capacitor are inbetween a battery and regular capacitor Can be used to run small things LiPo batteries are dangerous Have special storage in your lab if using these Wireless power delivery using varying magnetic fields https://fabacademy.org/2018/labs/fablabulb/students/nicolas-decoster/alumnus/projects/qc/
if anyone wants to see a vídeo about Lumafield testing 18650 batteries quality control https://www.youtube.com/watch?v=-Y23nfAOiXQ
in 2017 my student Jtravis made a Moss Battery for final project if anyone wants to see a vídeo about Lumafield testing 18650 batteries quality control https://www.youtube.com/watch?v=-Y23nfAOiXQ
Voltage measurement:
Current measurement: (11:04) measure magnetic field - pickup coil that can sense the changing magnetic field
Fading led Pulse width modulation to appear to fade Vary the on vs off time
Charlieplexing Makes a 5x5 led Pins can be high, low, off (output) Control n x n-1 leds This is set up as an array, but can be in different formats
RGB led Created an array Code available to use online
Bright leds These leds are supper bright Don’t need a current limiting resistor if you use a series of leds to add up to the voltage drop Use 20A mosfet 5A 30V Rdf Think of it like a variable resistor but usually use it as on and off, inbetween gets hot N mosfet is a sink of current P mosfet is a source of current “mosfets aren't linear so don't think of them as good amplifiers per se, but they can do really cool tricks around logic level shifting.” Ricardo Marques Use a pull down resistor so that they does not get stuck on by accident When heated more resistance
Displays LED Don’t recommend anymore OLED Generate light Cheep and easy
Thin film transistor TFT modulate light -use SPI
E link Hold light after powered off
- Light field Hologram like
Motors (11:25) Need h bridge to send current in 2 directions so the moto can go in both directions Use fatter traces for more current Small capacitor .1uF reduces noise Larger capacitor 10uF increases current Pulse width modulates to adjust the speed of the motor Gear head motors for lots of torque slow Little vibration motor in phones https://www.amazon.com/s?k=vibration+motor
Take prerecorded sounds and play over speaker hello.DFR0299.ino
**I2s protocol for audio only MAX98357A board ** Best way to make audio Wave table synthosys played over h bridge
Make solenoid coil with N mosfet attached to coiled insulated wire
Servo Always 50 htz pwm Provide ground, power, signal Motors must vary current Some motors use brushes BLDC (brushless DC motor Triple halfbridge A4945 chip Use when you want smooth continuous motion Stepper motors 2 sets of coils Odd and even are connected together Energize 1 set of coils will make the magnet move Specified by angle of the step and holding tork and current Sinasoidal cycle makes the motion smoother Use when want to continuously vary, but controlled With position measurement acts like a servo Easily available at low cost Servo Need to continually vary with 2 h bridges DrRVs425 chip has 2 h bridges and more DRV8251ADDAR simple, just 2 h bridges TB67H451AFNG,EL Much more substantial
Hockey pucks = solid state relay (11:54)
Shape memory alloys Artificial muscles using conducting thread Better then the shape memory alloys Soft robotics Vary air pressure to make things move