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Build the Hardware Components

Here you will learn how to build the 2log hardware components.

Disclaimer

Software, schematics and building instructions were made to the best of our knowledge. We provide them here free of charge because we think it could be of use.

However, we don’t take any responsibility nor liability for using this software nor for the installation or any tips, advice, videos, etc. given by any member of this site or any related site.

1 - Build a 2log Dot

Learn how to build a 2log Dot

The 2log Dot is a smart RFID reader that can read almost all common RFID cards. Its main purpose is to allow users to authenticate themselves with their smart cards in the system. For example, to log on to a machine.

The 2log Dot is based on the ESP32 and the PN532, two components that are used very often in the maker scene and are easy to obtain. Thanks to the modular design and the exposed GPIO pins, the 2log Dot can be extended at will.

The PCB

The 2log Dot board is a joint project which was developed together with the Technik Kultur Saar e.V. - Many thanks to Matthew for this contribution! In this repository you will find Gerber files for the 2log Dot board.

Order the PCB

  1. Go to https://jlcpcb.com
  2. Click on “Instant Quote”
  3. Click on “Add gerber file” and upload the .zip file you can get from here .
  4. Do a few necessary changes (let the other settings as it is):
    • Choose the number of pieces (Quantity)
    • Choose your favorite PCB Color - We prefer black ;)
    • Select the appropriate Layers:
      • L1: 2logDot-F_Cu.gbr
      • L2: 2logDot-In1_Cu.gbr
      • L2: 2logDot-In2_Cu.gbr
      • L2: 2logDot-B_Cu.gbr
  5. Proceed with the checkout and complete the order.

Congratulations - in a few days you will have your 2log Dot boards in your hands!

Get the Parts

The PCB consists of a 4-Layer stack. All required parts are through hole components with the exception of the capacitor C1 which is a combined footprint. Besides the PCB itself you need the following parts:

  • 24 Led WS2812B Ring with 4 contacts (diameter 66mm)
  • SMD Capacitor 5mm diameter, about 10uF
  • (alternative) THT Capacitor, about 10uF
  • Wemos D1 mini ESP32 (ESP8266 will not work)
  • PN532 RFID Reader V3 (red modules, sold under elechouse brand or clones)
  • mini pushbutton (the tiny black/silver ones)
  • (optional) 14 Pin Male and 13 Pin Female 2.54mm Pin Header/Socket for expansion port

Renderings

Assembling

To build a Dot you need a soldering iron with a fine tip, solder and some stranded wire.

I highly recommend using the template that can be clamped between the reader and PCB. This ensures that the LED sits above the PN532. This avoids ugly shadows. you can find the stl file here: https://gitlab.com/2log-io/hardware/2log-dot-case

It’s a good idea to put the ESP loose on the pins first, while soldering the pins tight to the board. This ensures that the ESP can be plugged in later without any problems when it is time for its turn. gi

Next, the button can be soldered on.

Solder the pins to the PN532. Also here it makes sense to insert the pins loosely into the board during soldering. Otherwise it can happen that you solder the pins a little bit crooked. Then they no longer fit into the PCB and you have trouble.

Now you can connect the reader to the board. In between comes the template that we printed out earlier with the 3D printer. Make sure that the recess in the template is positioned so that you have free access to the pins for the LED ring.

Now we can solder the capacitor and take the opportunity to cut off the protruding pins of the PN532.

Next, the ESP can be soldered.

Now we can work on the LED ring. For this I took copper wire and stripped it. Next, the stranded wire is tinned and soldered to the contacts of the LED ring.

Bend the pins upwards and put the ring on the template. Here you have to thread the stranded wire through the holes of the board and solder it from the backside.

Congratulations! You now have a 2log Dot.

The case

The case can be printed with normal PLA. Get the stl files from here. I particularly like the matte look of the Extrudr NX2 black matte. For the lid, simply laser a circle with a diameter of 70.5 mm. The material used for this is BLACK & WHITE 9H04 SC.

Flash the Firmware

  1. Make sure that the drivers for the serial adapter of your ESP32 and the Python tool “esptool.py” is installed.
  2. Then download the latest firmware build from our CI Toolchain here: https://gitlab.com/2log-io/2log-dot/-/jobs/artifacts/main/download?job=build
  3. Connect the dot with a micro usb cable to your PC and flash the binaries with the following command to your ESP:
esptool.py  \
            -b 460800 \
            --before=default_reset \
            --after=hard_reset write_flash \
            --flash_mode dio \
            --flash_freq 40m \
            --flash_size 4MB \
            0x1000 bootloader/bootloader.bin \
            0x10000 2log-Dot.bin \
            0x8000 partition_table/partition-table.bin \
            0xe000 ota_data_initial.bin

You may need to add -p /dev/<serial-adapter> with the path to the serial adapter in case the system can’t detect the serial adapter automatically.

2 - Build a 2log Switch

Learn how to build a 2log Switch

The 2log Switch is a smart wireless socket that can switch power and measure energy consumption. It communicates via WiFi with the 2log server and ensures that only authorized users can use the machines. By measuring the power consumption, the system knows exactly how long the machine has been in use.

Supported smart sockets

Theoretically, any tasmota compatible, ESP8266 based WiFi socket is suitable. Depending on the type, the software from our repository has to be adapted a bit.

To turn a smart socket into a 2log Switch, the 2log Switch firmware must be flashed to the device. For this purpose a USB Serial Adapter (FTDI) is required.

Shelly Plug S

Officially supported is currently the model “Shelly Plug S”. By the way, this is also one of the few models for which correct CE certificates could be provided.

To flash a Shelly Plug S socket you have to do the following steps:

  1. Download the firmware binaries from our CI Pipeline
  2. Open the housing of the socket by loosening the screw on the back.
  3. Connect the serial programmer (This blogpost shows how to connect the pins)
  4. Flash the firmware with esptool
    esptool.py \
        --chip esp8266 \
        --port /dev/tty.usbserial-UUT1 \
        --baud 230400 \
        --before default_reset \
        --after hard_reset write_flash \
        -z \
        --flash_mode dio \
        --flash_freq 40m \
        --flash_size 4MB \
        0x0 /build/bootloader/bootloader.bin \
        0x10000 /build/2log-switch.bin \
        0x8000 /build/partitions-single-1MB.bin