iot-temp-sensors-sd-card

atmega328 + onewire ds18b20 + ethernet w5500 + sd card this is a variant of this project with sd card support

• general wiring colors used

  • black GND, red 5V/3V3
  • orange MISO ( slave transmit to master )
  • yellow MOSI ( master transmit to slave )
  • green SPI CLOCK
  • blue SPI slave chip select
  • violet serial transmission line ( debug )

• schematics

• notes about sd card spi

features

• atmega manage only webapi
• html pages and javascripts moved to sd card; index.html and app.js need to be copied to SD card

install

• tune variables in particular remember to disable ENABLE_CORS
• set temperature sensors description into app.js sensorDesc
• disable debug mode

debugging

• program atmega and make it running within its webapi ( say at 10.10.4.110 for example )
• open vscode and drag into index.html and app.js ( you may need to download a copy of jquery and open it to enable intellisense of $. functions )
• enable debug mode
• set baseurl to atmega eth address
• enable CORS

memory considerations

using w5500 save up to about 5.5k flash bytes

roadmap

• currently sd card used to discharge flash from weight of html/javascript and at the same time to allow easy debugging/editing from pc ; subsequently sd card will be used to log data so that the index.htm can contains a graph of temperatures history

• this version uses W5500 but simply commenting Ethernet.h and uncomment UIPEthernet.h allow to run through enc28j60 ; to make it run in the 32K m328 flash would need to disable UDP that should save 5k flash while another possible 1.2k save could from this pr