Guide for ESP32-Sense Development Kit

Transcription

1 Guide fr ESP32-Sense Develpment Kit 1. Overview The ESP32 tuch sensr develpment kit, ESP32-Sense Kit, is used fr evaluating and develping ESP32 tuch sensr system. ESP32-Sense Kit cnsists f ne mtherbard and multiple daughterbards. The mtherbard cntains a display unit, a main cntrl unit and a debug unit. The daughterbards have tuch electrdes in different cmbinatins r shapes, such as linear slider, wheel slider, matrix buttns and spring buttns, depending n the applicatin scenaris. Users can design and add their wn daughterbards fr special usage cases. The fllwing image shws the whle ESP32-Sense develpment kit.

2 2. Related Resurces Set up Sftware Envirnment ESP-IDF is the SDK fr ESP32. Yu can refer t Get Started fr hw t set up the ESP32 sftware envirnment. ESP-Prg is the debugger fr ESP32 that features dwnlad and debugging functins. ESP32 IT Slutin ESP32 IT Slutin prject is based n ESP-IDF and cntains multiple prjects. Please refer t Build system and dependency fr hw t set up and cmpile the prgrams. ESP32-Sense Prject cntains the prgrams fr ESP32-Sense Kit that can be dwnladed t the develpment bard t enable tuch sensr functin. Hardware Manuals Please refer t Espressif website fr the hardware resurces including schematics, PCB reference design, BOM and ther files. Please refer t ESP-Prg fr the intrductin t the debugger. Related Resurces Espressif website ESP32 prgramming guide: It hsts extensive dcumentatin fr ESP-IDF ranging frm hardware guides t API reference. ESP32 tuch sensr design: It is the reference design manual fr the ESP32 tuch sensr system. Technical Supprt If yu need technical supprt regarding ESP32-Sense Kit, please submit a new issue referring t the ESP32-Sense Prject. Hw t buy WeChat Accunt: espressif_systems Purchase cnsulting

3 3. Preparatin Install verlay If plastic is used fr the verlay, the recmmended thickness is 3 mm r less. Because air reduces tuch sensitivity, any air gaps between the daughterbard and verlay must be eliminated. Yu can use duble-sided adhesive tape t fill in the air gap. Fr the daughterbard with metal springs, 7 mm stud blts shuld be used t install the verlay. Install daughterbard Use a cnnectr t cnnect mtherbard with daughterbard. Yu can use fur 7 mm plastic stud blts t have the daughterbard steadily parallel t the mtherbard, as shwn n the image belw: Set ESP-Prg debugger ESP-Prg is used as the prgram dwnlad tl and pwer supply. ESP-Prg has tw sets f jumpers: IO0 jumper and pwer supply jumper. Chse 5V pwer supply fr the latter. IO0 can be used bth fr selecting bt mde (dwnlad mde r wrking mde) and as a tuch pin. As a result, it shuld be discnnected if used as a tuch pin in wrking mde. The image belw shws the settings fr ESP-Prg.

4 Cnnect ESP-Prg with mtherbard The ESP-Prg has a Jtag interface and a Prgram interface. Cnnect ESP-Prg and the mtherbard thrugh the Prgram interface. Dwnlad prgrams Run make menucnfig t cnfigure the cnfig settings fr ESP32-Sense Prject, as the screensht belw shws. Run make flash t dwnlad prgrams int the develpment bard.

5 Replace daughterbard ESP32 will detect the divided vltage f the vltage divider n the daughterbard when it is pwered n t identify different daughterbards. Re-pwer n the develpment bard after replacing the daughterbard. 4. Hardware Resurces 4.1 Mtherbard Functin Blck Diagram The image belws shws the functin blck diagram f the mtherbard.

6 Mtherbard Cmpnents The display unit includes three segment displays and an RGB circuit. The debug unit includes the ESP-Prg debugger interface. The main cntrl unit includes the ESP32 mdule. The mini USB is the pwer supply. Pwer Management System The mini USB and ESP-Prg can bth be the pwer supply fr ESP32-Sense Kit. They d nt interfere with each ther thanks t the prtectin dide. The mini USB can nly serve as the pwer supply, while ESP-Prg als supprts autmatic firmware dwnlading. The figure belw shws the schematics f the pwer management system.

7 Display Unit The display unit n the mtherbard can intuitively feedback tuch event. The three 7- segment displays shw the lcatin f the pad that is being tuched and the duratin f a tuch event. The segment displays are driven by CH455G chip, and cntrlled thrugh I2C interface. The RGB LED reflects the clrs when a tuch event ccurs. When a finger mves n the slider, the RGB LED will shw the change f clrs. The figure belw shws the schematics f the display unit:

8 4.2 Daughterbard Divided resistance The tuch electrdes are arranged in different cmbinatins depending n the applicatin scenari. Each daughterbard has a vltage divider that has a unique value. The prgram running n mtherbard reads the divider value thrugh ADC and thus each daughterbard can be identified. The vltage divider is shwn belw:

9 The divided resistance n the mtherbard is 10 KΩ. The table belw lists the divided resistance n each daughterbard. Daughterbard Divided resistance (Khm) ADC reading (Min) ADC reading (Max) Spring buttn Linear slider Matrix buttn Duplex slider Wheel slider

10 5. Applicatin Prgrams ESP32-Sense Prject within ESP32 IT Slutin repsitry cntains the applicatin prgrams fr ESP32-Sense Kit. The directry structure is shwn belw:. main evb_adc.c //Identifies different daughterbards thrugh ADC. Sets unique ADC threshld fr each daughterbard. evb.h //Cnfigures settings fr mtherbard, including tuch threshld,adc I/O,IIC I/O, etc. evb_led.cpp //Initializatin prgram f RGB LED. evb_seg_led.c //Driver fr digital tube. evb_tuch_buttn.cpp //Driver fr tuch buttn. evb_tuch_wheel.cpp //Driver fr wheel slider. evb_tuch_matrix.cpp //Driver fr matrix buttn. evb_tuch_seq_slide.cpp //Driver fr duplex slider. evb_tuch_slide.cpp //Driver fr linear slider. evb_tuch_spring.cpp //Driver fr spring buttn. Kcnfig.prjbuild main.cpp //Entry pint. Makefile sdkcnfig.defaults 5.1. Cnfigure Settings When using verlays f different thicknesses r materials, users need t reset the change rate f tuch readings n each channel, that is, the sensitivity. This parameter is calculated frm the pulse cunt value. The calculatin frmula is: (Nn-tuch value - Tuch value) / Nn-tuch value, where "Nn-tuch value" refers t the pulse cunt value when there is n tuch event, and "Tuch value" refers t the pulse cunt value when a tuch event ccurs. Users need t take a measurement and btain these tw values. When the system is initialized, the tuch threshld is autmatically calculated frm the change rate f tuch readings. The tuch threshld is directly prprtinal t the change rate. When the change rate is set, users can write it int evb.h file.

11 5.2. Dem Spring Buttn Matrix Buttn Linear Slider Wheel Slider

12 Duplex Slider it slutin/blb/master/dcuments/evaluatin_bards/esp32_sense_kit_guide_en.md#52 dem