Week 11 - Input devices NOTES

Here you will find my work description during this eleventh week

General info

• Course
• Assignment

Class notes

Weekly reviews :

• Paul O’Neill (Lorain CCC)

• Heidi Hartikainen (Oulu)

• Juan Felipe Enriquez Fiallo (ZOI)

• Massimiliano D’angelo (Opendot) => travelling, next week

• Anders Alnor Mathiasen (Spinderihallerne)

• Edgar Eduardo Cartagena Ocampo (Yachay)

Raw class notes

sensors

• buttons (pull up Cf hello.button.45.c) - debouncing
• Motion detector PIR pyroelectric (hello.HC-SR501.py) mesure temperatur of your body
• sonar (ultra sound or optical time-of-flight (high res)) to measure distance (hello.HC-SR504.c) does work well if there is an angle, use 2 pins, 1 for trigger, other for echo, use timer to measure time, set the timer as the same frequency as the processor
• magnetic field sensor, field has a direction (hello.mag.45.c), read datasheet to know wich pin read (divide by 1.28???) to reduce the noise, read it 100 times, can be used to know the up side and the down side becaus of earth field
• temperature (NTC, RTD) Cf hello.temp.45. trick : use 4 resistors and measure the difference, amplify ?
• Light photo transistor (IR or visible) Cf hello.light.45, use a pull resistor, tip : separate sources of light
• acceleration 3 axis, not velocity but acceleration (upside down Z change because gravity is acceleration) Cf hello.adxl343 : tip reflow to solder the sensor (using the heat gun) use I²C (protocol), digital interface, init the communication, configure, 3 pins to the ground to reduce the noise, 6 axis, with gyroscope
• sound microphone, to mesure sound Cf hello.SPU0414HR5H, analog is more complex to process
• step response mat.blackshaw made a touch pad, matthew.keeter made a multitouch capasitive:
• loading : 1 electrode
• transm/recieve : 2 electrodes (better to avoid depending on the groom ?)with pullup & pull down look at the code to get some tips, like filtering noise see also doc2586.pdf.
• vibration piezo
• force flexture
• image camera, webcam (using libuvc) Webrtc is a standard easy to implement (see video.html source js) (chrome needs https!), using mods (OpenMV chip ?!? openmv.io 65$ from sparkfun, pixy cam cmucam) Recommanded WebRTC linux + webcam