Wireless MultiMeter (WMM) KIT

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KIT step-by-step construction guide, part 2 of 2

RX circuit wiring

Back to the project << >> goto part 1/2



WMM KIT 1 contents (picture)

  1. DMM (Digital MultiMeter) M830D
  2. Nokia 3310 LCD
  3. RX circuit
  4. RX-433 module
  5. SIL contacts
  6. Piezo buzzer
  7. 9V battery clip
  8. TX circuit
  9. TX-433 module
  10. Flatcable


 Blue= TX (DMM, TX circuit and module)

 Black= RX (RX circuit and module, LCD, Buzzer)


  Step 9: Nokia 3310 LCD (pictures)
LCD prepare 1
  • This left picture shows what we have at this stage.

  • Now get the flatcable (8-wired) ready.

  • Strip the flatcable, twist and pre-solder the wires and cut the ends.

  • Pre-solder the LCD-contacts (only topmost side.)

  • Solder the flatcable onto the LCD-contacts.

  • Now you should have something like on the right picture.


  Step 10: Nokia 3310 LCD (pictures)
LCD prepare 2
In some cases, the little black LCD-contacts connector is a little loose. This may result in a flickering display. You may tighten this connector by inserting little wooden toothpicks in the corners. Then cut the toothpicks just above the connector.


Finish by soldering the other end of the flatcable to a SIL-connector.




RX circuit (picture and drawing)

Overview and pinout.

  • JP1: LCD
  • JP2: RS 232 (only for bootloading and debugging)
  • JP3: RX-434 module, power:
1  +9V input from battery
2  input from RX-433 module
3 NC (no connect.)
4 GND (to battery and RX-433)
5 LCD contrast adjust input
6 +5V output (to RX-433)


RX-434 module


Overview and pinout.

1 gnd
2 digital output
3  linear output
4 Vcc
5 Vcc
6 gnd
7 gnd
8 antenna (30-35cm)

  Step 11: RX-434 module and power.
connection to RX circuit
  • Shorten the RX-434 modules pins and presolder them.
  • Connect the 9V battery clip to the 6-pin SIL-contact.
  • Connect the RX-434 module to the 6-pin SIL-contact.
  • Solder a 30-35 cm antenna (normal wire) to pin 8 of the RX-434 module.




Step 12: Buzzer.

connection to RX circuit

Now connect the buzzer wires to the RX circuit.
  Step 12: RX circuit.
  LCD and JP3 connect. Calibration.


  • Connect the 6-pin SIL to JP3.

  • Connect the LCD to JP1.

  • Plug in a 9V battery.

  • Adjust the LCD contrast by holding JP3, pin5 high during boot. Release when the desired LCD contrast is reached.

  • Turn on the DMM and see if you can receive a signal.

  • Enhance the RX-434 module signal reception by adjusting the red coil (in the middle of the PCB.)




Back to the project << >> goto part 1/2