So now I have the bug, and I'm actively saving my pennies to buy a Labradar Lite.  Since the original DIY trigger thread is kind of zombified, I figured I'd just start a new one, particularly since I have questions that weren't touched on in the old thread.

Like, how would I attach a recoil trigger to a 4" barrel revolver?  To a 1911?  To ANY automatic pistol that doesn't have an accessory rail?

I think the Velcro strap concept might work for a revolver, though it might need some extra "oomph" to stay positioned.  But what about auto pistols without a rail?  Off the top of my head, I can picture something that clamps on the front of the trigger guard, but I don't know how practical that might be.

Also, have there been any "refinements" in sensor choices?  Is the little mechanical vibration sensor still king of the DIY trigger?

I'm looking forward to getting a LR, but I can be (a little) patient.  The weather can't stay killer hot forever, but it looks like it'll hold on for a good long while.  That makes waiting a little easier...  

IMO you're overthinking it.

Yes mechanical triggers are still the best. They use tiny springs that when moved via motion close the circuit.

As fast as attaching goes, you can do Velcro, some do little HDD/neodymium magnets to stick it to the frame/slide, or, if all else fails, you can simply hold the trigger cord in your hands with the trigger itself sticking out between fingers. I've done that plenty of times with my LR.

Sure, you can 3D print mounts, and I have on several occasions, but that's more for a clean look that pure functionality. Heck, for rifles you can literally drape it over the rail and it will work.

So, don't overthink it would be my suggestion.

I was apparently WAY overthinking it.  Holding the trigger while I grip the pistol never occurred to me…

OK, off to start sourcing parts!  Assuming the spring-type sensors are still the bee’s knees, that is.  

Yep, as far as I know. If you already the part I I'm sure you're aware they make them that you can just buy if you want. So you don't HAVE to DIY one, but it's a simple project if you're looking to do it for fun.

I like to do DIY stuff, and I have some ideas about how to do a trigger.  I am quite handy with a soldering iron, and for a simple vibration switch that just has to close between the tip and ring on a mini-stereo jack, the electrical stuff is pretty much trivial - though fun.

The other part, some sort of container to protect the switch and allow me to hook it onto a firearm, that's potentially different.  I'm pouring through the older thread for non-3D printed ideas (I don't have room for a 3D printer).  I may ask for more details, or recommendations for sources...

Once you get a LR you may find you don't need a remote trigger. I've never experienced an issue with a non-triggered event unless I forgot to arm the system before firing. I shoot on a busy range using a camera tripod to raise the level of the LR to the height for off hand shooting a pistol. Keep the muzzle about 6" from the side of the LR.

I picked up some motion sensors since their cheap and have them on the shelf just in case one day I find a need. Just hasn't happened yet.

There seems to be a wide variety of personal experiences with Labradar and its trigger.  I’ve read reports of people being able to shoot .22 Shorts on a busy rifle line with all sorts of large bore rifles going off around them, and I’ve read reports of people who couldn’t get the unit to recognize their .45-70 firing while they were all alone in the desert.

So I want to be prepared for issues before they arise.  Having a recoil trigger may mean I can use the Labradar despite having a crowd of other folks on the line with “458 HolyCow Magnums,” or it could mean that I have it but don’t need it.  I’d be happier with the latter (those HolyCow Magnums give me a headache).

But in any case, I think it’s important to have good information before one dives into a “not inexpensive” purchase like the Labradar.

Agree with all of the above stories and will add a thought for the beginners...

Whenever you work hard on test ammo and don't load at the range, it hurts to fire a sample and have a hole in your data due to a missed trigger event.

Before you stop loading after making those test rounds, consider making enough extra rounds to help set up the shooting position, the trigger levels, boresight, season the barrel, etc.



I tried the LR internal trigger when they first came out, and eventually switched to the external trigger.

When you have an external trigger, manipulating the gun or dropping the bolt on an AR can false trigger the LR, so I also jumped to running LR from a tablet in order to arm and disarm to avoid false triggering and the fuss of deleting noise.

I found running from the external tablet much easier than running from the LR buttons that meant I had to stand up to reach over or break position. Pushing those buttons to delete a false shot was also an opportunity to misalign the LR. The external trigger is more reliable in terms of capturing shots, but it is also sensitive enough to cause lots of false triggers.

I also really liked the remote arm/disarm in order to avoid breaking position at the bench. Keeping the muzzle and LR well aligned to each other is important regardless of the trigger method.

Also, I end up with many "guests" on my LR who are not used to load development or lab work. They tend to forget they are "leashed" to the LR and want to jerk the cable when they are done shooting a string. I started using a magnetic cable saver to prevent them from jerking on the connector.

YMMV

Literally just solder it together, stick in a small section of round bic pen, and pot with epoxy.

Hold between thumb and forefinger of off hand. Should be plenty of movement to trigger.

I received my sensors in yesterday's mail.  They are WAY more sensitive than I'd believed.  Clipped a couple of jumpers between the sensor and the leads of my meter, and boy was I surprised at how easily the sensors were tripped (activated? closed the circuit?).

My "saving my pennies" days are behind me, as my beloved wife, ever the sane one, asked "are they going to get any cheaper?"  Of course not.  "So just order it."  So I did, and it's now in town, delayed by the shipper's issues with stupid high temperatures and the whole liability thing of having drivers get heat stroke just driving around.  That's a little frustrating, but I think I can handle it.

OK, now that I have my Labradar, I have a couple of questions.  When using a recoil trigger, is the position of the unit relative to the muzzle particularly important?  

The manual has guidelines - not terribly restrictive ones - but in particular I’m interested in using the Labradar with pistols.  It says to have the muzzle even with the side of the Labradar and about 6” away.  Isn’t that all about the internal trigger?

Anyway, another question has to do with battery life.  How long will the 6 AA batteries last in normal usage?  My power bank won’t be here until Wednesday, and I’d like to run the Labradar before then.

Yes, it's still important to get the muzzle offset correct. It uses it to back-calculate the muzzle velocity. The LR doesn't pick up the first doppler read until about 5-10 yards out depending on projectile. So it then works backwards based on information it has to determine its best guess as to what true muzzle velocity is.  The offset helps as it has to factor that offset into the calculation since the trigonometry of said offset makes the projectile appear to travel slower relative to the doppler panel.  It isn't a huge discrepancy either way, but I try to get it as close as I can to the stated offset.

6AAs won't last long. Maybe one session. It eats them pretty good. I actually have rechargeable lithiums that I use in mine (but you have to be VERY particular about which ones you use, they have to be rated for 3s configuration, and the vast majority are only 2s rated).  I like that because it keeps pressure off the USB port which has been known to be fragile in the past. I only use an external power bank if my AAs onboard die. That said I'm probably the exception here as most people use a power bank. Note the battery life indicator only works accurately when using alkaline cells. Anything else and it's going to read almost fully charged until it dies.

Thanks!  Given the calculations involved, the muzzle position makes a lot of sense.

Most battery level displays are built around alkaline batteries and their characteristic voltage decline curves.  On the other hand, non-alkaline cells don’t use up their chemistry the way that alkaline cells do, so simple voltage monitoring doesn’t tell you much.

Knowing that 6 AAs won’t last a long time is helpful for planning.  I’ve seen a lot of discussion about the micro USB port being touchy and fragile; I’ll make sure I don’t put any strain on it beyond plugging a cable into it.

Now I need to get another SD card.  The manual says to use SDHC, not SDXC cards, so I’ll have to pay attention when shopping.  It also recommends against using micro cards, and given the hassle I’ve had with my MagnetoSpeed, I’ll stay clear of them for this application. But my stash of SD cards is either SDXC and/or micro SDs, so a new card is needed.  The manual doesn’t say, but I assume the device will format the card if necessary.  It looks like it uses a FAT32 format, so there’s nothing fancy going on there.

Standard formatting works.

Just keep the card 32GB or less. 64GB is SDXC. 32GB and less is SDHC. Technically speaking 2GB and less is SD. But we don't really worry about those guys these days.

The card can't be too big data wise either or it won't work..don't remember what size is the limit so look...and yes its simple plug and play..

It's 32GB max.  This means the unit doesn't have to figure out what file system to use, and it can simply access the card with "hard coded" routines.

It turns out that I have a 32GB SDHC card on hand, so I'm going to try it out later today*.  I'm going to run the device with a USB power supply, and make sure it sees my card.  I'm also going to try to get used to the display, how the buttons feel, and so on.

I was surprised at how light, yet solid the Labradar is.  While it doesn't look it, it should be very stable with just simple support from a tripod.  Most of the mass is at the bottom, even without adding 6 batteries.  This is good because where I'll be shooting (at first, anyway) doesn't have a dedicated shooting bench, so I'm going to be using portable stuff that could shake (I run into things, it's one of my super powers).  I think the Labradar on a small tripod will be just fine on the platform I'll be using.

I'll be using a couple different approaches in building triggers.  Since I got a bag full of them, but only one cable, I'm looking at ways to use the cable with more than one sensor.  Or I may find a scrap cable (or just a 1/8" stereo plug) in my stuff.  It's all "organized," but it's certainly not "catalogued."  

*While looking over my SD cards, I found a 256MB card.  Unopened, never used.  I just have no clue what I could use that card for...or where it came from.

I thought the SD card had to be 16GB. Believe it was in an email exchange I had with the LR folks, but don't hold me to i. When I changed a 16GB card it worked and had plenty of memory for several outings. Not positive what size card I tried before that.

ETA: If you have a 32GB and it works, please let us know.

I thought it was 32GB, as 32GB is the largest SDHC card. I have no idea how a 16GB could work but a 32GB wouldn't.

I don't have a 32GB around or I would check. Just a few 128s and a few 16s. I use a 16GB for my LR.

LR sells the 16GB card with preloaded FW, but just read on the LR site's FAQs a 32GB or less card will work....so I've been mistaken all these years. ;)

https://mylabradar.com › faq
Frequently Asked Questions about Labradar and its operation | Labradar
The flashing blue light on your Labradar indicates the SD card is not compatible. It must be 32GB or less, SD or SDHC. Micro USB cards are not recommended. Do a FULL Format of the SD card using FAT 32 and try the card again. ... LabRadar provides minimum/maximum velocities, extreme spread, average velocity and standard deviation of a shot ...

The manual says “no more than 32GB” and “SDHC, not SDXC” card.  So when I get to it this evening, I’ll see what the machine says about my 32GB card.

I have a 32gb Sandisk ultra sdhc and it works great.

Well I soldered one of the sensors to some wires to start building a trigger.  DANG those are teensy wires!  Especially the copper wire...

Anyway, I'm fairly comfortable with this first try "working", but it ain't nearly as pretty as I want.  And to me, "not pretty" is pretty close to "it's going to fail or short."  I did use my "third hand" soldering aid,and I used a clothes pin to hold the sensor while I was working on it so I didn't squeeze the thing too hard.

So the next time I wire one up, I'm getting out my super magnifying, self lit specs and I'm going to use tinier tools (even my "jewelry grade" round jaw pliers were way too bulky).  But it's going to take a lot more prep to do the next one, and to make it to my standards.

The first one I tried to solder using rosin core solder was a disaster, to get a good solder joint I ended up getting too much heat in the vibration sensor and ruined it.  Those tiny wires on it are a B%(*&.  The next one I soldered I used excess rosin on it, the solder joint flowed instantly and perfect without overheating the small sensor.  35 watt soldering iron.

Yeah, I need to use a lot more flux, no doubt about it.  And at least two different "third hand" aids, so I can control the sensor's wires AND the wires I'm soldering to them.  

And lots of light and magnification.  I may use both my fancy wearable magnifier and my wife's lit magnifier; that's a challenging combination for any freehand work, but with everything locked down, it's doable.  Getting all the parts firmly positioned, so I only need to worry about where the iron and the solder are should make it much less of a problem.

I used my smaller, 25W soldering iron for more precision and control.  But my technique was off for a lot of reasons.  While I got a workable sensor out of the process, I'm just not happy with it, and I don't think it's rugged enough for the kind of handling a trigger would need to put up with.  Not from actual use, but from the handling needed to use it.

I'm curious if anyone's had problems with trimming either the main lead or the fine copper lead.  If I can at least shorten the big one, getting a clean, physically stable connection would be much easier.

Very important. https://www.ar15.com/forums/armory/Had-a-hell-of-a-time-getting-reads-from-my-Labradar-with-a-can-/42-535810/

The end of the can has to be even with the side of the LR, and 6" +/- 1" to the side. I was getting frustrated on a trip awhile ago, because the only thing wrong was the end of the can was 1.5" in front of the LR.



https://smile.amazon.com/RIIEYOCA-Replacement-Equipment-Installed-Microphone/dp/B0B3MMXMYN

I hadn’t found that 4-pack of cables, probably because I was looking for “headphone” cables, not “mic” cables.  I put it on my “wish list” for later.

Anyway, I set the unit up yesterday, plugged in the date and time and fiddled with the menus.  And my case and power bank were delivered as well.  That’s a nifty power bank, especially for the price.  Very well made and finished.

It’s still too DANG hot to go to the range any time soon, so I hope to play with the Labradar in my back yard with an Airsoft pistol.  It should clock in the “archery” range, and it’ll give me a chance to get the feel for using the device.

In researching the whole recoil trigger concept, I’ve found a lot of people have gone WAY farther than just hooking up a vibration sensor to the trigger port.  They’ve added resistors and capacitors to filter the sensor’s signal, hooked them up to oscilloscopes and measured the tiny jitters from the sensor after the initial trigger event, and so on.  On the other hand, folks here (and elsewhere) who just connected the sensor straight to the port have not reported any problems.  I gotta wonder about all that extra work…

Before I ordered mine over a year ago, I think I read those same posts.  If they were the same posts, the gentleman that was using the oscilloscope and designing minimal circuit to smooth the signal,  said it was completely unnecessary, just wire it up directly.

That's what I got from that particular guy - IIRC he was on The Highroad.  

There's another guy in Oz who just added the filter components because "the microphones supplied by Labradar have a low pass filter in hence the cap and resistor".  (In the first post...)  Anyway, a low pass filter on a mic will also knock down "not gunshot" sounds, to help avoid high pitched interference.  So whether that was even worth bothering with, the guy seems to have had fun doing it.  

This afternoon, I got out all the magnifiers, lights, etc. and worked on making another trigger.  I had success - after a real failure.
Here's the ugly one I did first:
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And then another.  I was SO happy with the soldering.  Then I used the heat gun to shrink the heatshrink...
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Oh, so they're really easy to melt...good to know.  Grr.

Finally, I did another.  Good soldering, maybe better than the first one today.  I used a small chunk of heat shrink on one lead, shrunk with the side of the soldering iron tip, only at the wire end.  Then electrical tape...which didn't want to perfectly stick, but it's still OK.
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I'll connect the good one from today to a 1/8" jack and use a male-male stereo extension cable to hook it to the Labradar.  That will give me the flexibility to have the cable go where I need it to - and stay out of my way.  Next up is building one that is wired directly to the stereo cable.

I didn't want to be stuck with a one length trigger since I didn't know how I would be really using it and whether a long cable might be beneficial.  I made mine plug and play, to use with any mic cable extension.

Probably don't have enough posts for image to show until moderator comes along.



Only "problem" with the plug in is if it is in line with more than subsonic blackout recoil, it will unplug.  Not really a problem, just turn it around or set it up 90 degrees from recoil.  I just use velcro to

attach it, or hold in off hand with a handgun.

I've soldered about 6" of wire to my sensor, and the stereo panel jack is soldered to the end of the wire.  That gives me some protection against motion all by itself.  I'll post a few pictures once I finish up that particular trigger.

I think I/we have covered the DIY recoil trigger angle pretty well.  But now there's something else that needs discussing.

Any Labradar you get is NOT usable out of the box.  It comes with cables and manuals, and that's about it.  So there are some accessories that are definitely required.  Others, not as much.

FIRST: something to hold the Labradar up.  Yeah, guys.  The thing doesn't even have cheesy "feet" like a $200 flat screen TV.  So something to hold it up and let you point it appropriately is necessary.

I have a mini-tripod we got a long time ago so my wife could do more professional photography of her jewelry work.  She moved up to a different setup, so the tripod is available.  It adjusts from 7" to 9" high without extending the legs.  The legs don't go flat, but the center tube makes a 4th leg, which seems pretty stable.  It also has a bubble level in the pan/tilt head, which I think is useful.

NEXT: power.  Unless you want to keep Duracell in business by yourself, AA battery power is at best a backup plan.  So some kind of USB power bank is needed.  Labradar warns that some such units don't have very good regulation (they make it sound a lot worse than that).

I bought Labradar's power bank, and I'm impressed with how solid it is.  It's priced pretty competitively too.  On top of that, I don't see a way for Labradar to say "you used a crappy power bank" if I use theirs and something bad happens.

THIRD: aiming.  Pointing the thing at the target is part of the setup and I have yet to find a review, comment or other statement that indicated the user loved the "sighting notch" built into the top of the unit.

After spending a lot of time online looking at the large variety of different gadgets available to use for aiming a Labradar, for anywhere from not much to "holy cow!"  Then I found a discussion that was pretty frank.  "I use an empty ballpoint pen tube."  "I just put a soda straw in the groove; it's all I need."  So since I have both straws and "about to be done" cheapie pens, I think I'm covered.

FOURTH: SD cards.  Not "100% necessary," but yeah, pretty necessary.  So far, it looks like all you need is a "no more than 32GB" SDHC card.  There are "more than a few" sources for these cards, and even more than a few "good, reputable" sources.  No big sweat here.

Have I missed anything?  I'm not saying "let's make this a definitive list of what people should get" or anything like that.  But I honestly want to make sure I haven't missed anything..

If you have access to a 3d printer, there are quite a few options for sights you can bolt on.  Also the battery pack holder works good.

The other thing that you are missing on your list is something to transport it in.  It doesn't come with a case.

Highly recommend the Pelican case. I found mine in Amazon warehouse for next to nothing. Then I just used a hot wire table to cut out the foam.

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I bought the soft, padded case.  I’m kinda impressed with it too.  You’d expect it to fit, but it also has some nice features, like it opens all the way out.  There’s a front pocket to carry cables and battery pack, and an inner pocket for manuals.

However, if I could find any Pelican case for “next to nothing,” I’d jump on it.  The difference between a nicely fitted soft case and a hard, weather proof case is all about stowage.

I was about to start a new thread until I read this.

Got my LL yesterday. Played with it last night, then played with it this morning. I haven't shot my long range rig all summer as I had started working on a new load right before I killed my old chrony (left it out in the rain.....worried about killing it with fire for 26 years, then killed it with water). So, I was reluctant to jump into long range development with no clue as to velocity data.

So this morning, before work, I piddled a while in the barn and figured out that I could set my LL on my barn shooting bench and get ~80% of the unit to have a clear path to my 100 and 225 yard targets (longest I can shoot from barn). But my offset is only maybe 3" between bore axis and the edge of my LL.  I fired 3 shots with my 'new load'. All gave readings and all were good hits with strong indication that the load's going to pan out well. But to make this work in the existing space (read: without building a shelf outside the barn window) I had to position my muzzle maybe a foot in front of the unit. Muzzle sticks out of the window at an angle, unit is just inside the window at the same angle.

(Note: I do NOT want to bring that muzzle inside the window and touch off a big boomer in my barn. That's bad for my ears and bad for my windows).

This particular load uses a very high-BC bullet (G7: 0.401) that, under my conditions, only decays ~100' for every 100 yards of travel. So roughly 1' of speed for every 3' of distance.

Am I correct to assume that having my muzzle ~1' in front of the screens is, most likely, causing my MVs to read very slightly high? With this load I'm looking at ballpark 0.3'/s. Completely negligible.

Likewise, a more modest BC bullet (using a straightwall case as an example here with a .25 G1BC) decays maybe ~330' in 100 yards, or very roughly 1.1'/s for one foot of muzzle placement error.

Is this roughly correct? Am I seeing this correctly?

Are you really worried about being way less than 1 FPS off on muzzle velocity?  It's doppler radar so all the actual readings in the track are as accurate as its particular hardware can support.  The muzzle velocity it displays is calculated from the first several velocities/distances it records, therefore it is assuming the face of transmitter/receiver is the muzzle location.  If you were a whole yard off in your actual muzzle location you would still be less than 3 FPS off on the displayed/calculated muzzle velocity on any high powered rifle.  Technically, the calculation of the displayed muzzle velocity would show lower than actual with the muzzle being behind the radar and higher than actual for muzzle being in front of the radar.  The amount off of the calculated muzzle velocity in practice where you are only a few inches one way or the other is pointless IMO.  Way less than 1 FPS.  

I agree that 1’ or even 5’ is pointless. I just want to make sure I’m understanding correctly that it really is only 1’ or so.

Trigonometry is a thing.

The first 12" in muzzle offset creates a 1 FPS error for every 700 FPS. If you're 5' of muzzle offset you're getting to be over  1% off. Maybe that's a big deal. Maybe not.

Some people need more accuracy than others.

What you're saying is that if I'm less than a foot off the muzzle (center to center, I assume) I'm looking at, with the rifles I am worried about the most, ~4 FPS or less.

Yeah, that's meaningless to me.

Haha fair enough.

I keep mine at 12" that way at 6" or even 18" away I'm never more than 6" away from where it thinks I am.

And frankly that's just due to me being OCD. I have zero need for that level of accuracy myself.

But just wanted to note the math in case others DO need that level of accuracy. At any rate, it is probably less error than the LR introduced by extrapolating the MV in the first place.

If I'm not mistaken, you are talking about offset to the side?  I believe that arowneragain was talking about front to back offset, having only a 3" side offset at all times.

I was, but his point about the side offset was relevant also, so I just went with it. It's still good info and I'd wondered about the side offset too.

I'd blame it on drinking...but I don't.

Sorry!

Oh don't be. This labradar opens up a whole 'nother world and I am certain I'll have more questions in the future.

Too your original side offset thing, I've shot so many pellets in front of the labradar, lots of them standing free hand and  I never noticed any difference in displayed muzzle velocity based on the few inches difference on side offset.  I hace a .22 PCP currently tuned to a low 22 ish foot pounds that under regulation gives an extreme spread of 5 fps if I shoot enough, not uncommon to shoot 10 shots with a 2fps extreme spread.  I think I'll test that out with it when it's not so damn hot and humid.  Set it up for 12" offset and shoot strings at 6,12,18 inches side offset and see if there is a difference in reported muzzle velocity.

A fairly big thunderstorm just went through and dropped the temp a lot.  Got the labradar, 22 PCP, and rest out and set up.  Temperature was climbing quickly while I was setting up and over 80% humidity.

So I didn't shoot long strings, turned out it wasn't necessary.  I set the labradar's offset to 6 inches and fired 5 shots with center of muzzle exactly 6 inches from side of labradar, then moved the labradar to

12 inches to the side and fired another 5, doubling the distance I told the labradar my offset was.   I was very surprised at the difference.

muzzle 6 inches from side of labradar:  906, 909, 907, 908, 909 FPS

muzzle 12 inches from side of labradar:  871, 873, 873, 870, 872 FPS

36 FPS is a massive difference for anything, doubly so with diablo pellets.

First string was exactly what I expected from the pellet I used, the second string blew my mind it made that much difference on the placement of the muzzle.  

Was it because I doubled the offset I told the labradar, in other words if I told it a 12 inch offset and moved the muzzle 6 inches would it make the same difference?  

I'll have to check later, it is already terribly uncomfortable outside and I put everything away.

Wow. So that tells me the LR uses a MUCH shorter distance of travel as a proxy for extrapolation of the velocity. Like, VERY short.

My calculations were the assumption of a 30' proxy. I'd have to back into the answer but mathematically it seems a lot shorter than 30', which is what I've heard in the past.

Actually I don't think it does, don't waste your time on doing any calcs.  On both my shooting lanes I have POOR conditions for radar, I have always had the labradar as close to the bore as I could(6"), never tried anything else.  With the testing I did today, I'm almost certain it is more my poor conditions than anything else, larger offsets have the projectile being picked up too late downrange and then the backscatter becomes very problematic.