Lightbulb altimeter testing

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Dipstick

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I need some recommendations for making a lightbulb tester for my egg timer builds. I have been using igniters to test but want to save them...

I bought some cheap lights on Amazon thinking anything would work, but these don't. Any recommendations?
 

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Good old incandescent christmas tree bulbs work fine, what you have there looks to be LED's any they have to have both a current limiting resistor and polarity correct to work (iirc). I have found in most cases the older style christmas tree bulbs take a bit more juice to light than ematches so if the bulb lights so will most ematches. I use different colored bulbs.

https://www.google.com/search?biw=4...qs=mobile-gws-lite.0.0l5#imgrc=KeTRYDrrA9HAvM41QtgYDYZJL._SR500,500_.jpg
 
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I need some recommendations for making a lightbulb tester for my egg timer builds. I have been using igniters to test but want to save them...

I bought some cheap lights on Amazon thinking anything would work, but these don't. Any recommendations?
Your LEDs will work if you put a series resistor on them, anything from 100 to 1000 ohms should work. Also you need to get the polarity right, fortunately there are 2 options to try.

Throw the ones away you tried, you burnt them out.
 
Another problem with LED's is that they might light dimly from the trickle continuity current, which is from 100 uA to 500 uA depending on which Eggtimer altimeter you have. Incandescent Christmas tree lights won't light unless you pump a decent amount of current into them, and there's no polarity to worry about. A package of 100 that you buy for a few bucks from a discount store at a post-holiday sale will last your forever.
 
At least with the LEDs I used, I also needed a parallel resistor to get the continuity check to pass. It was something large, I forget how many ohms though.
 
The AltAcc manual recommends a Type 194 miniature bulb. Available almost everywhere.
 
These worked well for me:
https://www.amazon.com/gp/product/B07T579FK7/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1
I just cut them off the wire and use different colors for each stage of deployment:
green: drogue primary
red: drogue backup
blue: main primary
orange: main backup
Having different colors allowed me to see that my drogue backup actually fired before my drogue primary during vacuum testing due to different manufactures philosophy on triggers.
As a result I rearranged things so my backup altimeter became primary for drogue and my primary became backup for drogue.
 
You can also get "grain of wheat" bulbs which are quite small. They can even be turned into igniters a bit easier than using Christmas tree bulbs if you want.

The Xmas tree bulbs are probably a larger electrical load, compared to the grain of wheat, and a better test of the avionics.
 
I need some recommendations for making a lightbulb tester for my egg timer builds. I have been using igniters to test but want to save them...

I bought some cheap lights on Amazon thinking anything would work, but these don't. Any recommendations?
I've used miniature Christmas tree lights clipped from an old string with great success. Each bulb has a resistance of less than two Ohms and glows quite brightly but without burning out.
 
Ok folks, I feel like the MIT grads that couldn't pass the light bulb test right now... looking for some gentle help 🙂

I bought a string of old incandescent bulbs at a goodwill store. I can't get an individual bulb to light off a battery, but they work on the string...

I have been wiring one side to the tip and the other to the gold screw. With 25 bulbs on a 120v string, I am assuming 4.8 volts needed? My 7.4v LiPo didn't do it, nor did my 12v battery...ok, I am not hooking things up right...but not sure what else to do. Can I clip a piece off the string and use the bulb holder somehow? I welcome your suggestions lolIMG_20201128_123719.jpgIMG_20201128_123813.jpg
 
These!

They are $2.08 for 50 at Walmart. A lifetime supply. Colors work too.
 

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The problems I am running into are suggestions that aren't available at my Canadian Walmart or ship to my Canadian address because Amazon.com...was hoping someone would have a suggestion for me to get these working.
 
Ok folks, I feel like the MIT grads that couldn't pass the light bulb test right now... looking for some gentle help 🙂

I bought a string of old incandescent bulbs at a goodwill store. I can't get an individual bulb to light off a battery, but they work on the string...

I have been wiring one side to the tip and the other to the gold screw. With 25 bulbs on a 120v string, I am assuming 4.8 volts needed? My 7.4v LiPo didn't do it, nor did my 12v battery...ok, I am not hooking things up right...but not sure what else to do. Can I clip a piece off the string and use the bulb holder somehow? I welcome your suggestions lolView attachment 440198View attachment 440199
If the string is parallel wired then the bulbs like 120v. Do all the lights go out when you remove one bulb from the string?
 
They are wired parallel, so maybe they just need that higher voltage then. Thanks
 
The problems I am running into are suggestions that aren't available at my Canadian Walmart or ship to my Canadian address because Amazon.com...was hoping someone would have a suggestion for me to get these working.

Canada...critical bit of information we did not have.

They are available on ebay canada (shipping "may" be an issue). It may be easier to just use e-matches.
 
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I can't get an individual bulb to light off a battery, but they work on the string...
Almost certainly 120V bulbs wired in parallel.

I still recommend the type 194. Available almost everywhere including your local auto parts store.
 
Alright, auto supply store I do have...some gator clips and I am set for building and testing some more eggtimer fun😃View attachment 440265
@Dipstick I used automotive bulbs too. I have a 2000 VW Golf parts car and took a couple of side marker bulbs from in & soldered on some wires, which was a little tricky. They work great! :music1:
 
Here's what I do -- take it or leave it.

I bought a testing chamber and wiring kit from (can't remember the name of the company, they're out of business). A green and a yellow LED, with an inline resistor. Every time I buy a new altimeter, or need to check an old one, attach the wires to the alt, insert into jar and seal the lid, pull back on the syringe till it stops, drogue LED lights, slide it back in, main LED lights. Only thing I ever have to replace is the 9V battery.

The test kit is just a plastic jar, airtight lid, through which pass a wiring harness and a rubber tube for drawing out air.
 
Another problem with LED's is that they might light dimly from the trickle continuity current, which is from 100 uA to 500 uA depending on which Eggtimer altimeter you have. Incandescent Christmas tree lights won't light unless you pump a decent amount of current into them, and there's no polarity to worry about. A package of 100 that you buy for a few bucks from a discount store at a post-holiday sale will last your forever.

I use yellow LED's from Frys. Haven't needed a reistor to use them. I can see the very dim continuity current which is nice to see, they light up upon testing.
 
I use yellow LED's from Frys. Haven't needed a reistor to use them. I can see the very dim continuity current which is nice to see, they light up upon testing.
:eek:

No current limiting resistor? If not, something in the circuit is acting as a resistor and it very likely isn't designed to do that. That means you are over-stressing a component on your altimeter that may ultimately fail. You really want a CL resistor in series with an LED. Some LEDs now come with a CL resistor integrated. It's up to you, but I would not run an LED without some means of limiting current to a safe level for your altimeter (the spec on your altimeter's high-side supply device, if there is one, or your altimeter's low-side sink device).
 
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I used LED's for testing very early on in the Eggtimer Classic testing, because I had a package of 100 of them and I didn't have anything else to test with. Nice bright flash as they blow... however, the Classic will handle a lot more current than most other altimeters, so I would not recommend this in general. Wait until Dec. 26th, and you can buy a hundred miniature Christmas light for a couple bucks.

At some point, you will have to burn a few ematches for testing... factor that into your ematch buying requirements.
 
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