3- Electronic

Introduction

The calibration module in the Uvex3 spectro consists of a Calibrex1 electronic card and a few external components, namely a flat lamp and an Argon-Neon lamp for calibrating your spectra.

This set is built on the basis of an Arduino Nano circuit which allows to do many functions in local mode or in remote mode via a PC connected by USB. The printed circuit has been developed by us and its reduced size allows us to integrate it perfectly into the guide module. It is therefore not necessary to have special skills as an electronics engineer or to know how to program everything is already done and explained in the following lines. You can get the printed circuit by following the link indicated and order it online. All you have to do is send the gerber file also available in the rest of the article to the site before confirming the order. You will still have to download the Arduino programmer found on the net so I will give you the corresponding link. The specific program for this Arduino application has been developed by the team. It will also suffice to download it from this article and then transfer it to the Arduino using your PC via a mini USB cable.

If you do everything yourself it will cost you a fairly modest sum not exceeding 50 € for a complete Calibrex card (the printed circuit, the components with the Arduino Nano as well as the two lamps).

We can see on the photo above the set that we will test on the table before integrating it into the guide module. We see the two lamps (Tungsten and Argon-Neon) a switch to switch from local mode to remote mode, a push button to change function when we are in local mode, the external 12V socket, a red LED (power and indicator which indicates the mode), a tricolor Led to know firsthand the function performed, finally a mini servo to switch the reflector.

Principe.

Not many components on the PCB itself, it’s the Arduino that does almost everything. He manages :

• Lighting the lamps
• The cycle, calibration, flat, dark and acquisition
• Position the servo motor
• The Usb link with the connected PC
• Manual mode and remote mode
• External information lights
• Measurement of the temperature of the interior housing by an internal probe

The small blue transformer that we see in the photo acts as a voltage booster from a frequency generated by the Arduino. Two separate outputs (with 180 ° phase shift) we attack (via the two transistors T3 and T4) the two primary of the transformer to have an output on the secondary of the transformer an alternating voltage of about 200 V, which will be used to power the lamp of Argon-Neon calibration. The Tungsten lamp is lit by another output of the Arduino via the transistor T1.

The servo motor is connected to the M1 connector next to the blue transformer, and the temperature probe opposite to the P2 connector. All the LEDs are connected directly to the Arduino outputs via a current limiting resistor.

The regulator U2 is used to manufacture continuous 5V from external continuous 12V. It is used to power the 5V servo motor.

Nomenclature refer to the screen-printed map for mounting.

Components	Value	Details
U1	Arduino	Nano
TR1	Transformer to solder for CI	see above
T3, T4 Transistors darlington	TIP122	boitier TO-220
T1 Transistor NPN	2N2222	boitier TO-92
U2 Regulator 5V	7805	boitier TO-220
R1,R2,R4,R5,R6 resistors	4,7 Kohms	P= ¼ W
R3 résistor	24 Kohms	P=1 W
LR1,LV1,LB1,LRalim résistors	2 Kohms	P=¼ W
1 LED tricolor cathod commun	Diam 5 mm
1 LED red (light alim en 5V)	Diam 5 mm
1 switch , 2 positions	Diam 5,5 mm
1 pushbutton , fugitive	Diam 7 mm
1 femel chassis plug, le + in the middle	Diam 8 mm
1 associated male connector plug
1 bar support Nano (M/F)	2X31 *	pas 2.54 mm
1 bar M for connectors 3 points welding	1X12 *	pas 2.54 mm
Lamp tungstene (FLAT)	culot à vis	12V 0.2 A 2W

The printed circuit is made in China, by the company JLCPCB. I ordered from this manufacturer and the result is perfect, and very serious. The manufacturing quality is remarkable and the prices very low. Just click the surrounded « calculate » menu and take the default page and download the Gerber file as a zip file, all done automatically. I’ll give you a screenshot to show you what it looks like before the final order. You download the Gerber file that I give you. We can notice that there are two holes of 4 mm in diameter drilled, they serve to center the circuit in the calibration module and pass the lug which is part of the module.

PCB Prototype & PCB Fabrication Manufacturer - JLCPCB

Once received the components, the printed circuit and the servo motor, remains to solder the components and to assemble the whole in the Calibrex case. Here is the result: