As with droid #1, I'm using PC fan connectors to connect the dome electronics. This way I can unplug them from the power bus bars with a minimum of fuss. Most of the electronics only use the positive and negative signals, but the third signal can be used on the front logics to trigger the display of a text message.
It's just a matter of cutting the cable in half, and soldering one end to the wires leading to the part to be powered, and the other end to the power source. I always need to remind myself to cut a segment of shrink tubing and string it on before I start soldering.
Each part had been tested in isolation, and I finally had a chance to test them all together.
The green LED for the rear PSI was not as bright as I wanted, so I replaced it with a 10 cd, 3.2Vf, 20mA LED, and replaced its 1Kohm resistor with a 300 ohm resistor. Nice and blindly bright.
Ah, but how to mount the small circuit board? Tom Doucet's PSI holders include a backing piece designed to work with Mike Velcheck's PSIs. The board layout for Mike's PSIs is somewhat different, so I needed to clip all but one of mounting points.
With one of the two mounting holes on the board threaded onto the one mounting point that I left intact, I drilled a 9/64" hole through the other mounting hole, and through the PSI holder backing plate.
I used a 1/2" #6 nylon screw and nut to secure the board using the hole I just drilled.
The dome electronics are mounted onto the dome ring. I'm using six D Cells in series to supply 9 volts to my dome electronics. Experience with droid #1 shows that I can run the dome lights for months at a time without having to replace the batteries, but they do make the dome somewhat heavy. I was considering using C cells instead, but my sub-minimal effort to find battery holders for them at Radio Shack turned up empty, so D cells it is.
I still need to cut some segments of wire to finish the connections to the bus bars. I also need to purchase and wire up a white LED for the front holoprojector, I keep forgetting about that.
3 comments:
Victor, have you looked into RC LiPo batteries? They have a lot more longevity than Duracell and can be recharged. Pretty cost effective as well as lighter and smaller with much more M.A. capability.
alan
Alan,
Until your post I had never heard of LiPo (I am familiar with Lithium Ion, though).
They look like impressive technology, although I would want a supply of 9 volts, and my very brief search using Google turned up multiples of 3.7 volts.
I will give this some consideration.
Thanks,
Victor
Victor, I bet Mike is familiar with them. You are correct, the cells come in 3.7V so you could go with a 2 cell pack (they charge up over 4.1 volts fully charged and then go thru an electrical regulator to get back to 9.0V. But check with Mike, he will know.
alan
Post a Comment