June 27, 2008
about 2 years ago
If you’re thinking of bypassing the RCA jacks by tacking wires onto the pads on the solder side of the board, beware that the RCA jacks are SHORTING JACKS for some reason. Without a plug in the jack, the video is shorted to ground.
about 3 years ago
One solution is to put an unswitched load on the inverter ahead of the sequencer. This can be a length of EL wire (the minimum length specified for your inverter) if you want, but if you don’t have any use for always-on EL wire, you can substitute a capacitor.
I was using a “Big Boy Classic” inverter, which has a minimum length of 20 feet, which is equivalent to about 30 nF (equals 0.030 uF) of capacitance plus some resistance. A 33nF 300V disc ceramic capacitor worked fine and cost only about $1. I measured the frequency coming out of the inverter and the capacitor had the same effect as 20 feet of EL wire. There’s no need to simulate the resistance, just the capacitance. The capacitance required should scale linearly: 1.5 nF for every foot in the minimum length specified for the inverter.
Of course, this subtracts from the total capacity of the inverter. The Big Boy Classic is rated at 20 to 120 feet. So with the capacitor taking up 20 feet of capacity, that leaves 0 to 100 feet.
If you have an extra sequencer channel and a lot of faith, you can put the capacitor on an unused channel and program the sequencer to turn on that channel only when none of the actual EL wire segments is illuminated. This will work as long as you always have all the EL wire segments hooked up properly, and your software always does exactly what it’s supposed to do. Too fragile for my tastes.
Actually, the ratings on inverters are somewhat optimistic. If you load the inverter to its rated maximum capacity, you will see reduced brightness. If your project switches between short lengths and long lengths (total of all illuminated segments), you will notice the difference. You can reduce this effect by using only half or so of the rated capacity of the inverter.
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