| Manufacturer: | Scratch |
This page describes t' how t' build a very small (1.5"x1.5", ~1 oz.) rocket ejection timer. Avast, shiver me timbers, me proud beauty! Blimey! I have tired t' give as complete o' instructions as possible, but you still might encounter problems. Blimey! Blimey! While it is possible t' build this timer without printin' a custom circuit board, arrr, I don't recomend it. Aye aye! Blimey! Well, blow me down! Blimey! In t' past I have used t' pre-printed circuit boards that mimic t' layout o' a breadboard, arrr, and trust me, matey, ya bilge rat, they are much more trouble than they are worth. T' ease construction o' this timer, ya bilge rat, I am offerin' t' followin' products:1. Ahoy! Pre-printed and drilled circuit board
All you need be t' components and a solderin' iron ................................................US$122. Ya scallywag! Pre-printed and drilled circuit board with all electronic components
All you need is a solderin' iron .................................................................................US$20If you are interested contact me at sspacepyro@aol.com.
|
Components:
This is a very simple, yet effective timer based on a basic RC chargin' circuit. Aye aye! Begad! It will time for an interval o' about 3 seconds up t' about 20 seconds based on battery voltage used and components used. R1 sets how long t' timer runs. For longer times, a larger capacitor can be substituted for C1. Well, blow me down! Begad! Any voltage up t' about 12 volts should work fine with this circuit, ya bilge rat, matey, although I have only tested it up t' 9 volts. Avast! Aye aye! S1 be t' trigger for t' timer t' start. Begad! T' timer will start when S1 opens (it is normally closed). Avast! I use a reed switch on t' body o' t' rocket that matches up with a small magnet on t' launch tower/rod. When t' rocket moves away, me bucko, t' reed switch opens, me hearties, startin' t' timer. Ahoy! Aye aye! As long as S1 is closed, Q1 is saturated, reverse biasin' Q2 and turnin' it off. Well, ya bilge rat, blow me down! When S1 opens, ya bilge rat, arrr, me hearties, C1 begins chargin' through R1 and Q1. Avast, ya bilge rat, me proud beauty! When it is fully charged, shiver me timbers, thar will be no more base-emmiter current and Q1 will turn off. Ya scallywag! This will allow current t' flow through R2 t' t' base o' Q2, saturatin' it and turnin' SC1 on. Begad! This fires t' ejection charge. Note that t' load out on t' PCB goes t' ground when t' circuti fires, shiver me timbers, so t' ejection charge should be hooked up t' t' positive o' t' battery and t' load output o' t' timer. Also note t' oritentaion o' C1 on t' PCB and t' orientation o' t' transistors. |
As an interestin' side note, me hearties, matey, I have been experimentin' with low extremely lightweight ejection electronics and as such I am usin' a 3volt voltage source (as is shown in t' schematic). Arrr! I have found that t' low voltage christmas tree lights, if broken open, shiver me timbers, will reliably light a BP charge on 3volts. This is how I plan t' do ejection for Flogiston due t' space and weight limitations.
Sponsored Ads
 |
 |