UV-meter design
Introduction
LUVI is a simple design for a handheld UV-meter with an Erythema sensitivity curve. It uses as much as possible ready-made components and will need a minimum amount of soldering.
Early ideas on how to design the LUVI UV-meter that may be helpful to see the design choices that have been made and the different issues that have been looked at when making the design, are described at
Components
Box
-
Camdenboss
-
45 Series
- CHH451PBK - 45 Series enclosure, handheld electronics enclosure ABS
- 117.5 mm x 72.5 mm x 25.5 mm
- Integrated 9V battery compartment with clip
- Silicon rubber boot as option (delivered with each LUVI) CHH451PBK
- Farnell
- Dedicated rubber protection: CHH451BBK - 45 Series rubber boot, Size 1, Black
-
45 Series
- Design
- Factory-made cutouts for display, pushbutton and UV-sensor
- Factory-printed customisation
Display/voltmeter
- Murata 3½ Digit, LCD Display Digital Panel Voltmeter DMS-20lcd-1-5-c
- Application notes
- DMS Application note 3: Analog Common and Reference in-out
- DMS Application note 12: Signals with Zero Offsets
-
DMS Application note 2: Input Configurations, Power Supplies, and Ground Loops
- All models have an internal, 1- 2 microfarad, filter capacitor connected across pin 1 (+5V SUPPLY/+BATTERY) and pin 3 (5V RETURN/ –BATTERY) to attenuate high-frequency noise.
UV-sensor
Printed Circuit Board
- Holds
- UV-sensor mounted on a separate PCB to allow a 90 degrees angle to have opening at the front-side of box
- Diode for protection against battery reversal
- Ultra-stable 5 Volt reference voltage IC that powers all components
- Resistors and multi-turn potentiometer for the full-scale adaptation and calibration
- Resistors and multi-turn potentiometer for the zero-reading calibration
- Connector for pushbutton
- Wires to the 9V battery clip
- Display/voltmeter
- Needs careful adjustment in height when soldering. 3D-printed template for assembly is designed
Various
- 9V battery
Compliance testing
-
- Gives a good summary of the EMC standards
-
The meter needs to comply with general standards IEC 61000-6-3 and IEC 61000-6-2 which mandate for a battery-powered device:
- CISPR32 (Radiated emissions)
- IEC 61000-4-2 (ESD immunity)
- IEC 61000-4-2 (Electromagnetic field immunity 80 MHz – 2.7 GHz)
- IEC 61000-4-8 (Magnetic field immunity at 50/60 Hz)
Erik van der Bij - 1 August 2020