After the purchase of some hair thin (0.1mm) nichrome wire for low current igniters, I realized I would need a system to test said igniters
Thus the ICBM-Micro was created
What it lacks in safety, it makes up for in simplicity and portability
It runs of a internal 9V battery, and is controlled by a master switch and button
It was designed by me in Fusion 360 and printed on my Ender 3 V2
This is version 2, version 1 failed shortly after creation and was partly re designed to allow for easier construction and continuity indication
The general shape was based of the “Hollywood Handheld Detonator” often seen in media
This also allows it to be easily held and operated with one hand, and is quite compact
As said above, it was made to test low current ignition systems, this is because while the main ICBM arrangement works wonders, it can hardly be built into a small rocket, and with a reliable low current igniter a parachute ejection charge could be ignited in flight by a flight computer
It however does not fulfill specifications for actual rocket launches, due to the lack of a key switch, double button setup and adequate wire length
The main ICBM unit will continue to be used for that, and has so far worked with a amazing 100% reliability record (after switching to Nichrome wire)
It features a main ARM switch, a DETONATE button, and a continuity indicator
The circuit is as follows
Its quite simple
The positive of the 9V battery goes to both the NC and NO terminals of the button trough a switch
The normally closed is connected trough R1 (560 Ohms) and a LED to the ignition leads, with the normally open shorted to the ignition leads
This is to not let enough current pass to heat the wire, but enough to let the LED light up
The LED is also disconnected upon ignition due to this setup
The housing itself consists (not counting fasteners) of 3 parts
- The main body
- A end cap
- And a button plate to ease construction
They are held together by little plastic pins and friction
Fusion files will be posted at the end of this article, but I am not responsible for anything you might do with them, use common sense please
Not only can this be used to develop different igniters, but it can also be used with those igniters as a more portable and easy solution for testing pyrotechnic mixtures where the safety of the main ICBM is not required
It is small enough to fit in a jacket pocket with its ignition leads, and is fully self contained with its internal battery
As promised, here are the Fusion files (In a 7-Zip archive)
Its a bit rough, since it was not made for public release but just to work, but I cleaned it up a bit so it should be decipherable
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