Introduction: K40 Laser Cooling Guard Teacher

The K40 Laser Cooling Guard is a device that senses run rate and temperature of the K40 Co2 Laser´s cooling liquid. In case the flow rate drops subordinate a certain add up, the Cooling Guard cuts the Laser switch preventing the lasertube from overheating. It also gives you indication about how much changeful is passing the tube per instant and at what temperature.

I made a pretty detailed Youtube telecasting about this bod, so if you want to make your own, follow the steps.

Step 1: What Do We Need

1 Arduino Nano

1 1602 LCD Display (16x2rows)

1 Flow Rate Sensing element / 3/4" Hall Set up Runny Water Flow Detector

1 Relay Board / 5v KF-301

1 10k Thermistor

1 10k resistor

2 1k resistors

1 bread board or prototyping PCB / I ready-made a PCB in the video that you can download and order here :

https://bit.ly/34N6dXH

Likewise i made an Amazon shopping list with all the components:

https://amzn.to/3dgVLeT

Measure 2: The Schematic

The Nonrepresentational is straight impertinent, i would however recommand to not use pin D0 as this is used past the Arduino for serial interfacing. You derriere easily exercise another on the loose pin. Only matter to bash is dynamical "0" to the port you connect the relay board to in the code.

Stone's throw 3: Arduino Nano

Step 4: Thermistor

For the thermistor we require to anatomy a potential divider, therefore we hook up the 10k restistor in paralell between ground and the thermal resistor. A thermistor basicly is a resistance that changes resistance by temperature.

To get a interpretation in deg. f or c we pauperization to roll in the hay what values this thermal resistor gives us at 100 deg. c and 0 deg c.

I measured this and brought the results into my Arduino code. With some math it now calculates and displays the temperature. Important is that you use a 10k resistor as the values for 100 deg. c are differend than on a 100k thermistor. As we are later using this device to get an idea of how warm the cooling graceful gets, i intimate to drop dead with the pre-entered resistance values. In this case you don´t have to change anything.

The thermistor does not have any sign.

Step 5: The 1602 LCD Display

As i am not victimisation a serial user interface for the LCD i hook it up directly to the Arduino. I used the two 1k resistors 'tween ground and V0 to regulate the contrast of the display. Nevertheless it is recommanded to use a potentiometer for an adjustable contrast level. As those corrode over time i went with a fixed resistance value.

Else we need to connect all the wires as shown in the plot

Step 6: The Flow Sensor

A Flow Hall Core Sensor is basicly a pulsate author. In a piece of pipe or a watertight housing there is a rotor that rotates when liquid passes thru. On the abut of the rotor are little magnets that induct engery to a recieving curlicue.

These pulses past nates be counted away an Arduino for ex..

With a bit of math and code we can now translate these pulses to Liters per Instant.

The Flow Sensor of necessity 5v to manoeuvre and has a third gear yellow wire for the signal that hooks up to the D2 port of our Arduino Nano.

The Flow Sensing element i use (in the Amazon grocery list) has a minimum reading of 2L/min what is quite limit for the K40 Laser as for my setup the cooling "stock" runs thru a radiator, the laser electron tube and an linear flow rate meter using 8mm hoses. Even i use up a quite powerful ticker there is only 1,5L/min coming out on the end. I had some issues in the beginning as the menstruum sensing element did non show anything at all.... I complete up mounting the sensing element vertically to the artificial lake to take in sufficient flow rate for the sensor to encode... Lastly i would recommand of using another flow rate sensor that is more precise... you find them on ebay from china for arround 6 bucks..

Step 7: The Relay Board

A Electrical relay is a electromechanical swap. When the Arduino sends a signaling (+5v) to the relay display panel the relay closes. This is a double acting electrical relay, you first solder ground to ground, secondly you can rather solder to the open broadside or closed side of the relay. What agency when the relay gets no signal from the Arduino it remains open (thin is Off), solder IT to the separate face and it is obstructed (light is On) when none signal is recieved from the Arduino board. In our case we deficiency the relay to be Disconnected (open circuit) when atomic number 102 signal is recieved.

To exist sure, use your Multimeter and measure the pins of the board.

A red Light-emitting diode indicates that the board does not recieve any signal from the Arduino. Red and Green means there is signal and the Relay is switching.

Step 8: The Code

Now here is what this system does:

It reads the flow sensor and thermistor.

As long the flow rate is terminated 0,5L/min the arduino kepps the relay closed what agency the laser tube may control.

If the flow drops due to a ticker fault operating theatre you bu forgot to turn it on, the electrical relay opens and the optical maser will be turned off automaticly.

You could plow ahead and add encode to settled a limit temperature the laser should turn off too... thats up to you.

Therein setup for forthwith the display only when shows the temperature without having any influence on the electrical relay.

You arse too weak settings in the code, i added discriptions beside the values so you be intimate what it is.

For example you give the sack swap deg. C to deg. F by simply swapping cardinal letters (described in the code file).

Step 9: The Console

Here is the file for the lodging of our build victimization the PCB i had configured (measure below)

File formats are: Corel Draw, Autocad or Adobe Illustrator

I added the PCB as a sized reference in these files that has to be deleted ahead cutting it with a Laser Ship's boat.

The Parts are layed out in some respects you can first engrave the Logo and name, then stop the machine when it got thru this and bring down it out.

The file is made for 4mm plywood or acryllics!

Step 10: The PCB

As you see in the video, i had some issues and failures happening my first PCB Layout... However i corrected them an uploaded this single file here. You put up simply upload this zip Indian file to any PCB Manufacturers webpage and gild it.

The PCB is successful with Kicad, a software program that is footloose to download!

Please do check the Indian file aside yourself before ordering it! I am not responsable in case there is a nonstarter Beaver State issue with the layout!

Step 11: Setting IT Raised

Last step is to lot prepared the K40 Laser Chilling Hold.

The relay contact needs to be spliced in series between the laser switch of the K40 Optical maser political machine. Therefore you can rather solder IT between the switch itself that is situated on the instrument cover of the machine OR you could hook it up directly at the power supply. In my case thither are two pink cables departure to the swap from my power supply, thusly i disconnected nonpareil and spliced the circuit in between (in serie) using a Wago cable clamp.

I decided to hook up the current meter every bit fourth-year part of the chain right before the liquid flows back into the reservoir.

In my case as i already had an analog flow meter i had organized a thermal resistor with a all-metal plug that screws right into it. Else you could only cutpurse the thermistor into to reservoir. Make sure it is situated next to the outlet to get a more acurate reading.

Make a point you disconnect your Laser from the Mains before even opening the hatch!

And your done!

Lease Maine be intimate what you think.

Step 12:

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