Hardware and firmware to provide restricted access to dangerous and delicate tools. Built around an ESP8266 (WeMos D1 mini) and RFID-RC522 breakout.

Designed to be easy to build for all levels of experience - simply order the PCB from DirtyPCBs or OSHPark and solder the through hole parts to the board. Software builds through the Arduino environment and will flash directly to the WeMos board over USB.

To build a machine node you simply need to acquire a PCB - gerbers are available in the hardware folder - and order the parts listed in the BOM.

Schematic.

There are three power supply options.

• 12 V DC Power
  This is the recommended option. Populate the 12 V DC section of the schematic, and also C4 if you wish.
• 5 V DC Power (Untested)
  Populate the 12 V DC section of the schematic, and do not fit U2 or D2. Use a jumper wire to bridge D2 and connect the solder jumper JP1.
  There is no polarity protection in this configuration.
• 240 AC Mains Power (Untested)
  Populate the 240 V AC section of the schematic. There is a PTC fuse inside the AC-DC power supply U3 but there should be external fusing as well to protect small gauge cabling coming into the terminals.

The relay is rated for 250 V, 6 A max. If you are switching heavy loads it is recommended that you use this to trip an external contactor.

The default state is "Present" mode, that is, the output will turn on when the card is present and it will turn off when it is removed. An as yet untested mode allows the node to read a card once and then keep the output enabled until an external signal is received.

Feel free to test this mode out, you can modify settings in settings.h. Remember to include a button to allow the user to cancel their session.

Enclosure parts are for laser cutting and will fit a deep surface mount pattress box available from LAP. You need to countersink the "solid" back plate and fit screws through into the backbox compartment to secure the PCB in place. Nylon screws & nuts are recommended to secure the PCB to minimize any interference with the RFID signal. Typical metal faceplate screws are acceptable to attach the faceplate to the backbox.

• MFRC522 RFID
• ArduinoJson
• ESP8266RestClient

Modify settings-example.h and rename as settings.h.

Requires the Tool API server running somewhere accessible, at least until the cards have been cached.