Hi All, I am attempting to make my own laser jammer. After inspiration from the notchacotcha and not willing to spend $1000s on a commercial unit, I want to give it a go myself. I have purchased a couple of these Hybrid Pulsed Laser Diode with Integrated Driver Stage 70 W Peak Power 905nm should be closer to what actual lidar guns use. From what I can tell from the notes is that I need to a MOSFET driver which I found Elantec EL7104C or Micrel MIC4452. But now I am stuck on how to build it and code it. I would love some help, and it would be much appreciated. I was thinking of making a youtube video of the project. I recently purchased an oscilloscope and bench power supply. Thanks in advance!
What is your basic "jamming" plan? Blind yourself and everyone else within a kilometer or so, with reflections from an invisible, extremely high power laser?
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Because of the dangers to you and others I will not answer this question. Reason I do not know your qualifications and expertise in this matter.
Hi, @nikski
Welcome to the forum.
Please define "laser jammer".
How is it supposed to work and to jam what?
Can you please tell us your electronics, programming, arduino, hardware experience?
Thanks.. Tom.. 
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No, it is not my intent to hurt or blind anyone; less powerful options are available, and do not expect to use the full 70w potential. I just so happen to find these cheaply and with the FET included. This is for educational purposes only. I have bought a police-grade laser speed gun in which I want to attempt to "jam." I want to share if I can find a safe and easy way to build a jammer. I can code basic stuff and have messed around with some ESP32s for LORAWAN. I have never encountered using a MOSFET and MOSFET driver, but I do understand the basics. I have a general curiosity about lasing and RF.
I am also trying to build and understand a speeduino ecu to make my 2-stroke motorcycle EFI.
[Best laser jammer reviews: what are the top laser jammers of 2023?](https://link to commercially available laser jammers)
I DO NOT PLAN ON DRIVING AROUND WITH A HIGH-POWERED INVISIBLE LASER. I am a 42-year-old dad with two young children.
*pew pew
Nick
Main advice: DO NOT LOOK INTO LASER WITH REMAINING EYE!
Well, reading the datasheet it's not a full blown 70W laser as found in the more powerful laser cutters, but it can still be seriously bad for you: "these devices emit highly concentrated non visible infrared light which can be hazardous to the human eye. Products which incorporate these devices have to follow the safety precautions given in IEC 60825-1 "Safety of laser products"." The datasheet suggests you can get 40 kHz x 30 ns x 70W pulses which comes to 84 mW of output power, 17 times the power of a typical laser pointer (5 mW maximum) which is pretty blinding already.
For driving it, the datasheet says it all. Drive the gate at 5V or more (15V is mentioned as a good voltage, that would also be suitable for charging the laser) with a proper MOSFET gate driver. Pulse width at least 50 ns (that's pretty short even for an Arduino Uno or Nano; a single clock tick is 62.5 ns). I don't see a charge period mentioned, will be mostly dependent on stray resistance in your circuit such as wires and internal resistance of the power supply.
A decoupling cap next to the laser may be in order, if you want to run it at high frequency (1 kHz or more) I think you should use either a low ESR electrolytic or a ceramic cap.
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I can't believe that it is legal to use such a device in your territory.
haha thanks. I have IR safety glasses and only work in a closed workshop.
Can I control the Elantec EL7104C driver with a teensy 4.1 or a faster Arduino board?
Switching speed: Switching speed at gate depends on current and speed, charging the gate capacitance (typ. 300 pF) of the internal transistor. Reduced pulse widths, rise and fall times occur at trigger pulse widths < 50 ns. This also reduces the optical peak power.
Do you have a low ESR electrolytic cap you could point me to? 300pF?
I found this post which has a schematic in it, what level Schottky diodes and external resistors do I want? 15V 1A?
any more help on building this would be much appreciated!
Completely legal here in Massachusetts! always follow your federal and local laws, kids!
For power supply cap: I was more thinking of something to the tune of 4.7uF or 10uF, that will be more than enough. No specific pointers to parts; try digikey's search function. Low ESR specifically due to the high frequency pulses it has to deal with.
That 300 pF is the gate charge. As you can see in the datasheet there are also caps that are charged to pulse the laser (the MOSFET shorts them out through the laser diode), I didn't see info on the capacitance of those.
For the MOSFET driver have a look at the datasheet of the ones suggested in the datasheet of the laser diode. Likely you can find a reference schematic on how to use it. MOSFET drivers typically need external capacitors on the power supply line; if you use the same power supply for the driver and the laser they can share the bulk decoupling capacitance.
An Arduino will be perfectly fine to drive it. The shortest pulses it can do are 62.5 ns (use two PORT register calls, that gives a pulse of one clock tick). That's within spec, and I'm assuming - it'll be in the datasheet - that the MOSFET drivers are fast enough to follow this. Maybe you have to make the pulse a little longer, some NOP operations in between, to wait a few clock ticks? Interestingly I don't recall an indication of the longest duration the pulse may be.
Then what does the following mean?
The FCC strictly prohibits radar jamming. It is a federal offense with a fine of up to $10,000 for each conviction.
@JohnLincoln
It means the FCC strictly prohibits radar jamming. I agree. We should not jam radar nor do I intend to, and it is very illegal. Imagine jamming radar near an airport?
We are talking about light in the 905nm spectrum regulated by the FDA. Lidar is a laser NOT radar! Infrared, aka I.R. 700nm-1500nm. Radar is 400cm-1mm on the other end of the spectrum, with visible light in between.
Does anyone know what Uc,th is?
Hi, @nikski
You don't need a 300pF cap, and you can't get low ESR 300pF capacitors.
Sorry, but this shows you do not understand electronics principles, can I suggest you do some basic electronics before endeavoring to play with the jammer.
Tom..
U is the symbol for voltage, as in the concept, not the unit. Not commonly used but I've seen it before. C is charge, th is threshold.
So it's the minimum voltage to to get the laser to charge up to a level that it can do something useful.
I learn by doing. And maybe I could learn something from you if you explained it or pointed me to a video or article instead of judging me like an a-hole.