LEDs for Testing

[Deadhead]

Looking for LEDs for testing altimeters. Any links, specs, sources, or other info is appreciated.

I have both Stratologger CF and Eggtimer Quantum altimeters and want to play around and get more comfortable with the functionality without going through a bunch of e-matches. (I’ll save those for ground testing and flights.). Are there any “out-of-the-box” LEDs recommended or do all need an added resistor?

Thanks!

 

[jderimig]

An led by itself will present a dead short to your altimeter. You need to put a series resistor to limit the current. 500 ohms would be ok and limit the current to about 14 ma with a 9V altimeter. Any LED will do.

You can buy LEDs with built-in resistors, Here's an example https://www.amazon.com/50pcs-12V-3mm-red-LED/dp/B07P111B66?th=1

 

[cerving]

LED's also will light falsely due to the current used for continuity testing. We recommend using miniature Christmas tree lights... the incandescent ones. You can get a box of 100 of them on a string for under $10, just cut off a couple and strip/tin the wires. I think I've been using the same box I bought 14 years ago... and there are probably 3/4 of them left.

 

[NTP2]

LED's also will light falsely due to the current used for continuity testing. We recommend using miniature Christmas tree lights... the incandescent ones. You can get a box of 100 of them on a string for under $10, just cut off a couple and strip/tin the wires. I think I've been using the same box I bought 14 years ago... and there are probably 3/4 of them left.

Do you know how hard it is to find incandescent lights these days?? Or telling them apart from LEDs pretending to be incandescent?

Ps I tried to find some but gave up.

 

[RokitFlyr]

Do you know how hard it is to find incandescent lights these days?? Or telling them apart from LEDs pretending to be incandescent?

Ps I tried to find some but gave up.

Second hand store.

 

[jderimig]

LED's also will light falsely due to the current used for continuity testing.

Two-fer. LED's will also test if you have continuity current. There should be an large intensity difference between continutiy illumination and firing illumination right? Also the lumen output at continuity will vary depending on the altimeter used.

 

[Titan II]

Do you know how hard it is to find incandescent lights these days?? Or telling them apart from LEDs pretending to be incandescent?

Ps I tried to find some but gave up.

Amazon. Many places around Christmas. Also, they are very easy to tell apart.

 

[jgarbus]

https://www.amazon.com/Generic-Chri...ent+light+bulbs+12v,aps,131&sr=8-7&th=1&psc=1

 

[cerving]

Do you know how hard it is to find incandescent lights these days?? Or telling them apart from LEDs pretending to be incandescent?

Ps I tried to find some but gave up.

Search "Sylvania miniature Christmas tree lights". You'll get a zillion hits.

 

[cerving]

Two-fer. LED's will also test if you have continuity current. There should be an large intensity difference between continutiy illumination and firing illumination right? Also the lumen output at continuity will vary depending on the altimeter used.

I used to used LED's, but the Christmas tree lights more closely resemble the characteristics of an ematch (pure resistive load). And there are no polarity issues, either.

 

[mrwalsh85]

Do you know how hard it is to find incandescent lights these days?? Or telling them apart from LEDs pretending to be incandescent?

Ps I tried to find some but gave up.

...not hard at all.

I bought 2 full trays of Christmas lights after the holiday last year at 90% off. I'm set on lights for the next ten years.

 

[RokitFlyr]

I used to used LED's, but the Christmas tree lights more closely resemble the characteristics of an ematch (pure resistive load). And there are no polarity issues, either.

Which is why we used them for an alternate to e-matches back in the day.

 

[NTP2]

Amazon. Many places around Christmas. Also, they are very easy to tell apart.

Not online, at least I’ve had trouble.

 

[NTP2]

https://www.amazon.com/Generic-Christmas-Replacement-Incandescent-Pinched/dp/B0CRYZ3HT2/ref=mp_s_a_1_7?crid=26SGAQTUC0M0P&dib=eyJ2IjoiMSJ9.54oG2S3SgRGK4jkUW_lzGkftpWOKNJZI6Aj8kxKNncaJL8vjfGWwmOEutEpBZ-rjoRAh-VCHOenuiOeIsJu8qZOJYrY2CjEz9pEene0e67kk4dL4hG4I0vaJlB9RYw6hFbNqBNM4wnogZo8UUgZ_MakXFnRsfp-PqdYzYrHw8FADe28yQfpE-R62OLHjMcRnbO_y8wO3vA8FoGBaoh5MGA.oAtlH8y2eMwGH1OTwzLDyZoCkZfIjR8eJqPqUtOzdlU&dib_tag=se&keywords=incandescent+light+bulbs+12v&qid=1738521386&sprefix=incandescent+light+bulbs+12v,aps,131&sr=8-7&th=1&psc=1

Thank you!

 

[QFactor]

Looking for LEDs for testing altimeters. Any links, specs, sources, or other info is appreciated.

I have both Stratologger CF and Eggtimer Quantum altimeters and want to play around and get more comfortable with the functionality without going through a bunch of e-matches. (I’ll save those for ground testing and flights.). Are there any “out-of-the-box” LEDs recommended or do all need an added resistor?

Thanks!

Here are some pictures of the Radio Shack LEDs that I use when testing my Missile Works altimeters.
They have a built-in resistor; 680 ohms.

I have not tested them with my Eggtimer or Stratologger units, but I would think they would work fine.

Cris (cerving) is on this thread so maybe he can comment on them.

I've been using them for a number of years. Radio Shack does not offer them anymore, but you can
find similar ones on Amazon, etc.

These LED specs pretty much concur with jderimig's info.

 

[Deadhead]

LED's also will light falsely due to the current used for continuity testing. We recommend using miniature Christmas tree lights... the incandescent ones. You can get a box of 100 of them on a string for under $10, just cut off a couple and strip/tin the wires. I think I've been using the same box I bought 14 years ago... and there are probably 3/4 of them left.

Good idea but I can’t get anything incandescent in California anymore. Even Amazon won’t ship.

 

[K3LAG]

Altus Metrum sells LED's for use with their altimeters. They glow dimly when connected and brightly when the charge is set off. They might work on other altimeters as well that have similar characteristics but only trial will say for sure.

https://shop.gag.com/pyroled.html

 

[RoysRockets.com]

https://www.amazon.com/gp/product/B07YFBR3BZ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
https://www.amazon.com/gp/product/B07H7D8YH3/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

Unless Im missing something as to why you want LED, but these work every time, they show continuity on altimeters. Just insert the bulb wires, or take the light string and cut it in the middle of sockets and make testing leads.

 

[QFactor]

Altus Metrum sells LED's for use with their altimeters. They glow dimly when connected and brightly when the charge is set off. They might work on other altimeters as well that have similar characteristics but only trial will say for sure.

https://shop.gag.com/pyroled.html

I have tried LEDs similar to these on the Missile Works (MW) units. They always ended
up as crispy critters after a test. I contacted MW and they advised me to get a resistor
in there. I just so happened to have the Radio Shack LEDs from one of their massive
stock sellouts at a store closing. MW confirmed they would work fine, and they have.

 

[ksaves2]

Which is why we used them for an alternate to e-matches back in the day.

But............ The filaments were fragile and I was able to purchase a pile of ematches before they were temporarily cut off. Never did the "light" thing as it was too much of a PITA to break the glass off. I did learn to make some "nasty" ematches back in the day but again, too much a PITA to do and I just bought in bulk and store them in the proverbial "cool and dry" place so I was set for life. They fell off the market for a time with the LEUP snafu from years ago. Glad I bought before the hammer went down. I think they're easier to get now. Even got some off ebay and they were reliable. Kurt

 

[jgarbus]

Good idea but I can’t get anything incandescent in California anymore. Even Amazon won’t ship.

That's just ridiculous. Don't want to start some sort of debate on the topic but come on....ridiculous.

 

[Pilotx1]

menards and homedepot both had incandescent Christmas tree lights this past season, they're the cheaper sets. i picked up a 300 light icicle light set for just a few bucks

 

[Deadhead]

menards and homedepot both had incandescent Christmas tree lights this past season, they're the cheaper sets. i picked up a 300 light icicle light set for just a few bucks

Where you are I’m sure they’re available in a lot of areas. Haven’t seen anything but LEDs for a few seasons in SoCal. State law went into effect a while ago to move us toward new technology. I’m not opposed at all to new technology but they’re really pushy about it out here.

 

[Handeman]

Two-fer. LED's will also test if you have continuity current. There should be an large intensity difference between continutiy illumination and firing illumination right? Also the lumen output at continuity will vary depending on the altimeter used.

This will get you 100 bulbs for $5.

 

[Handeman]

That's just ridiculous. Don't want to start some sort of debate on the topic but come on....ridiculous.

What do you expect from the Republic of California?

 

[jderimig]

This will get you 100 bulbs for $5.

Get'em before the tariffs kick in. Save $0.50 now.

 

[Handeman]

But............ The filaments were fragile and I was able to purchase a pile of ematches before they were temporarily cut off. Never did the "light" thing as it was too much of a PITA to break the glass off. I did learn to make some "nasty" ematches back in the day but again, too much a PITA to do and I just bought in bulk and store them in the proverbial "cool and dry" place so I was set for life. They fell off the market for a time with the LEUP snafu from years ago. Glad I bought before the hammer went down. I think they're easier to get now. Even got some off ebay and they were reliable. Kurt

I used them quite successfully back in the day, before I could buy the chinese ematches on ebay.

I only broke the top of the glass bulb off so it stayed higher than the filament. I then ohmed the bulbs and threw out the ones that showed "open".
I then used a narrow tweezers to pull the shorting wire out from the base of the filament wires. That shorting wire is what kept the whole string lit if a bulb burned out. I then ohmed the bulbs and threw out the ones that showed "open".
I then twisted the leads of two bulbs together and soldered on some 24 ga. shooter wire. I then ohmed the bulbs and threw out the ones that showed "open" or twice the ohms of the others that were tested.
I then wrapped a paper tube around the two bulbs and hot glued the to bulbs in one end. I then ohmed the bulbs and threw out the ones that showed "open" or twice the ohms of the others that were tested.
At the field, I poured the needed amount of powder in the tube, folded the top over and taped it closed. Then used as ejection charges with a single altimeter. Never had a failure.

Started using ematches as I got tired of the huge amount of work it took to make the charges from the bulbs. I still have a container full of bulbs from the old xmas light strings. I kept all those bulbs when I replaced the strings with LED strings. No more tripped breakers on the xmas lights and I can run 8 - 10 strings together instead of just 3.

I use red and green on the drogue side and blue and yellow one the main side when testing altimeters.

 

[jgarbus]

This will get you 100 bulbs for $5.

Are these one and done being there 2.5v?

 

[OverTheTop]

I also vote for "grain of wheat" bulbs like cerving mentioned above. Buy them on the interweb.

If you are using LEDs then I suggest using a pair, back to back, so that polarity becomes unimportant. Don't forget to use resistors with them though .

 

[Handeman]

Are these one and done being there 2.5v?

Only if you use them for ejection charges. The ones I've used to test altimeters with 9V batteries have lasted through many tests.