found one of my old projects and decided to show it off - Page 1
Forum section: electronics / projects

author: carbon dude oxide
author_rank: Frequent Contributor
timestamp: June 13, 2013, 12:58:18 pm
content: hello every one, today was my last day at sixth form and i found one of my old projects which i used for an after school club which i though you guys might be interested in. so i present to you my remote explosives ignition project.It's purpose was to remotely and safely ignite explosives for ballistics club where we would launch tennis balls out of Pringle tubes otherwise known as the Pringle mortar.it comes with two separate launch keys and and switches so that a teacher has 1 key and a student has the other, that way it cannot be ignited by 1 person and have teacher authorisation to do so. It works by sending a 12V high current into some nichrome wire which is wrapped around a match, the current is set so that it makes the nichrome wire glow red to ignite the match therefore igniting the fuel for our projects.once the device is powered up there are two led's showing the status of each keyand one switched onand both activatedonce both centre red switched are turned on (i couldn't resist the missile style covers which also prevent you from accidental activating it, the centre panel will light up showing that the outputs are live and ready to launch. There are 3 outputs that can be individually ignited from the detonator.this is it during the early development stages:this is a short video of the first launch... well the fuel didnt ignite as we had the wrong fuel mixture but it still ignited the front.click me for the video - the link is here somewherea picture of a succesful ignitionTeardown time!This is where most of you are going to cringe, especially dave as i know he does not like bodge wire. Concidering the school i went to did not have any pcb etching equipment (untill i convinced them to get somei was stuck with solid core wire so i present the madness:the 2nd power rail for the 9V battery which is connected to the LED's and the front panel button'sthe back panel where the 12V input would go and the ignition linesthe main voltage input rails, notice the 3 core solid wire used for the high amps in the ignition side.the dpdt key switches, one side handeldd the LED's and the other handled the 12V for the main panel.the trimmer pots for the front panel LED's as they were all different brightnesses without them. the king of bodgynessthe initial making of the panel, this is before the bad spray painting job (it was my first go at spraypainting)click meand just for a bit of fun my match rocket as it is launching. it flew through the air about 5 meters and its only 2 match sticks[url=https://plus.google.com/photos/117230674360118100747/albums/5758603462155253265/5758732605765250098?banner=pwa&pid=5758732605765250098&oid=117230674360118100747]click here for awsomnessout of the whole of this project there are several parts i like very much and some i don't like, i defiantly like the front panel and they way that the switches work ect but i am not proud of the wiring on the inside but considering the materials i had at my disposal i think i did quite well.what are your thoughts on this old project now?

author: Alana
author_rank: Frequent Contributor
timestamp: June 13, 2013, 02:57:12 pm
content: Brings back memories of how i researched remote triggered firecrackers. At first i used some copper wire unwound from relay coil powered by NICD battery pack that could give some jucy amps on short circut, then i tried xmas lights blubs with broken off top so that filament was exposed and close to gunpowder.I may play with it again - this time with HV captitor discharge ignition.Thanks!