Anyone used LED buttons for the laser power and test button? I can’t figure out how to wire them up so the LED part comes on ONLY when the buttons are active.
Ulincos Push Button Switch U19 (one momentary and one latching)
I can make them work as regular buttons by wiring to NO and C. Which leaves the positive and negative lines (which I think are for the LED) unused. If I follow the manufacturing diagram I don’t know where to put the black negative line. As both laser power and test switches only generally use 2 wires.
For reference, I’m building a 60W laser and my Laser PSU wiring follows the attached drawing from Don. I’m just using a C3D board instead. Also including some pics of my custom control panel. Which i’m hoping to install tonight…
It looks like you would have to run 1 extra wire, connect the black wires of your buttons together and tie it to the closest negative point (on the laser psu, 24v psu, controller card negative, etc). I’m guessing that the ground wire is just for handling the small amount of current going through the led.
There are a lot of assumptions on how these will be wired. First, the LED does not have it’s own contacts to enable. It is relying on the switch contacts and common power to what is being switched. So think of the LED as being wired in series with the switch and power. Now this all assumes that the power being switched is 12VDC. The way I would wire it up would to use a relay. This serves to isolate the switch and LED functions. Using a DPDT relay, the switch turns on the relay, one set of contacts illuminate the LED and the other completes the path of control.
Here is my back-of-napkin answer. Don’t have the time today to check thoroughly … so check carefully.
Assumptions:
…The LED’s are 12V
… The LED’s are isolated from the switch terminals
… The Test Switch is a PB?
… The Laser Switch is alt on-off?
…The drop across D1 will not effect the L signals integrity. Rather not add another diode drop into the L path.
Operation:
When switch is engaged ground is provided to the LED for that switch.
R1 & R2 could be eliminated if you have a separate 12V supply. Otherwise you can use the LPS 24V supply with resistors to limit current.
D1 keeps the Laser Test switch from grounding the L signals mosfet output. Precautionary, depending on how L is connected to the smoothie may not need D1.
To size resistors need to measure the current draw at 12V across the LED. I can calculate these if you provide the 12V current.
5V versions of these switches would eliminate the resistors or a separate 12V supply.
Seems simple enough but I would test this on the bench so make sure that TL and WP are ground when switches are activated and open when not… verify I did not advise something stupid
@donkjr okay. Had to digest your sketch for a little bit. Not my area of expertise.
Anyway, this looks like it solves my wiring issue. Just need to get some diodes. Can you help with an amazon link for some good diodes or can I get them at a local auto shop?
Also check the pic below. Not sure my LPS has 24v line I can wire. Could I just use the 5v instead. The LED will still be plenty bright.
@Bill_Keeter
The PB LED draws 18ma (.018 amps) @ 12vdc.
I would guess you will draw about 7.5ma (.075amps) @ 5vdc. So your supply will see roughly 15ma for both switches if you use the 5v.
If your happy with the brightness at 5v, sure you can use the 5V as I would expect it can handle 15ma.
Any 1N914 diode should work. Search that # on Amazon there are lots of choices. A local RS, if you can find one, should have them. Again you may not need the diode.
These are momentary switches, which will work fine for the Laser Test but you need an alternate action or rocker switch for the Laser Switch ?? i.e it has to stay on or off …?
@donkjr decided to just run a relay for each of these buttons. That way I can physically separate the voltage going to the LED (12V) and WP/G (5V). And I can do the same for the Test fire button using LH.
Also for your other question. They make these LED buttons in both momentary and latching. So seeing the always on RED LED will help remind me “Laser On”.
A side benefit of these relays, is that I can still run the laser on switch in series with a physical water flow switch (with it’s own LED bulb).
@Bill_Keeter not sure of your exact circuit. Just note, if your having a relay that indirectly controls the enable circuit that may add more items that can fail in the ON state. It may not be obvious but make sure the circuit is designed for things fail in the “disabled” state :).
I choose not to put anything but a switch in line with laser control safety circuits.
A last hint since enable, fire and L are [internal to the lps] in the leg of an Optocoupler they do not like any voltage drop across a device that may be in series with that circuit. A switch is fine but a LED may create a problem.
I’ve been looking into a similar thing using 12V relays conncected to the switches to drive the lights and also the 12V relays would be used as the control leg to switch on larger 120V relays for things like water pump, air assist, and so on. Do the power diodes do the same thing? The things I was thinking of would not be momentary connections but rather continuous. Thanks!
