DB25 #9 — Knee High

I remember from childhood that things are supposed to be knee high by the Fourth of July. I don’t remember what things exactly. Corn? Mortar racks for holiday fireworks? The last of the glaciers? It was certainly one of those.

We dove into the corn case in the last installment, with the Case/New Holland diagnostic adapter. Today, the fireworks. I refer you first to the ”16 Shot Fully Flexible Rack w/Cobra DB25” (from Spirit of ‘76 Fireworks) for all of your holiday needs.

There are two major types of fireworks shows for the 4th of July. The first type requires two people: one to light the fireworks and a second to hold the beer of the first. The second type is the “Ooh” and “Ahh” type put on everywhere from the village green to the National Mall. The former type typically runs in an ad-hoc way, more or less, until the fireworks, the beer, the matches, or the fingers run out.

In the second case, the elaborate planning and choreography on the ground contribute as much to the effect as the firework shells themselves. Mortars are arranged, aimed, and fixed to racks. Electric igniters are attached and routed to a controller, typically able to run a show comprising a series of cues — individual fires.

COBRA firing systems supplies the entire pyrotechnic enterprise, tonight's shows included. Many of their cues are sent over DB-25 cables.

COBRA supplies power on pins 10,11,12,13 and 23, 24, 25 – these odd and even pins form a cluster on one side of the connector. The remaining pins are dedicated to each of 18 individual cues. So what are these cues? power or data?

Why not both? The DB-25 connector is the honey badger of electrical connectors. It simply doesn't care. You can get DB-25 connectors with pins rated for several amps a piece at 250 volts. Whether you are looking to blink and LED or send a smoke signal, you can probably do it with a DB-25. A COBRA firing system connects to igniters that fire with about an 1 amp at about 1 ohm.

I hope all your fireworks and DB-25 connectors are safe today. I'll take apple pie with both!