Zman wrote:
Strictly speaking, you should have a removable key interlock somewhere on the power side of the controller. Many people use a shorted phono plug in homebrew controllers. My controller, and the ones we build in class, use a lot of household electrical components; they are cheap and easily handle the current loads of my non-relay controller. The interlock is half of a dual wall socket with a shorted power plug and the launch cable is an extension cord which plugs into the other socket. The female end of the extension cord plugs into a lamp cord tail with clips. A light switch is the main power ON/OFF switch. The most expensive part is a 30A pushbutton fire switch. A current limited LED, piezo buzzer, and small pushbutton all in series make up the continuity circuit (about 12 - 15ma through the igniter with a 13.8V lead acid motorcycle battery during test). We use a power strip at the pad end for drag races.
The controller/battery is very reliable and lights 7 motor BP clusters (Estes igniters) without a problem. It also fires copper bridgewire igniters (James Yawn style) and has even launched a modroc on bare nichrome.
Strictly speaking, you should have a removable key interlock somewhere on the power side of the controller. Many people use a shorted phono plug in homebrew controllers. My controller, and the ones we build in class, use a lot of household electrical components; they are cheap and easily handle the current loads of my non-relay controller. The interlock is half of a dual wall socket with a shorted power plug and the launch cable is an extension cord which plugs into the other socket. The female end of the extension cord plugs into a lamp cord tail with clips. A light switch is the main power ON/OFF switch. The most expensive part is a 30A pushbutton fire switch. A current limited LED, piezo buzzer, and small pushbutton all in series make up the continuity circuit (about 12 - 15ma through the igniter with a 13.8V lead acid motorcycle battery during test). We use a power strip at the pad end for drag races.
The controller/battery is very reliable and lights 7 motor BP clusters (Estes igniters) without a problem. It also fires copper bridgewire igniters (James Yawn style) and has even launched a modroc on bare nichrome.
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Gary Bolles
summum jus, summa injuria est
Gary Bolles
summum jus, summa injuria est
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