Hi,
Yes, like Lance, I usually get just the F-F dupont cables (note that various lengths are available), but I always have a reel of "Bare Tinned Copper" wire and a few pin-headers to hand. IMHO they can be a little stiff and the core very thin, so they do fail occasionally; but equally I've often got caught out by the ready-made croc. clip jumper cables, in assuming that one end is actually connected electrically to the other end.
As you've just raised the issue, a conventional (model-makers') "Servo" receives variable-width control pulses from the PICaxe, but is also connected separately to a d.c. power source (typically 0 and 5 volts). So a relay wouldn't be appropriate (or necessary). I would expect a Servo (for each "gate") to be fine, or a (geared) stepper motor might be worth considering. Otherwise you have the complication of a reversible dc motor, gearbox, limit switches, lots of connections and program code to worry about.
Now, here is my "review" of those 50 watt floodlights. But first I must emphasise that mine was very cheap, particularly being locally-sourced, so it might be a "fake" copy of a "cheap" Chinese product (or worse) and / or have been repaired (the mains lead soldering is particularly shoddy). First, I had examined quite a few ebay listings and there are subtle differences (although they do all claim 50 watts). One actually claimed 48,000 hours "lifetime" and another that it uses SMD2835 LEDs. Most manufacturers appear to rate these LEDs at 0.25 watt, but I did find one as 0.5 watt, therefore one watt per LED might be a rather "optimistic". The mains lead is ridiculously short (<10 cms) but well covered with sealant where it enters the case. The front cover / lens also has an apparently good quality (silicon rubber?) "O"-ring in a groove, so it might actually achieve IP66, even after re-assembly, which as I said before is just a matter of 12 Posidrive screws.
The circuit board is indeed aluminium-backed, which touches the back-plate, but there was no "heat-sink compound" between them. The backplate gets too hot to touch, so I hate to guess the temperature of the LEDs and other components. The front of the PCB is almost entirely copper-clad, with just narrow channels to isolate the "tracks", presumably to act as further heat-sinking. The copper is then coated with an insulator, so it's not easy to follow the tracks, but it can be seen that there are groups of 4 LEDs at the corners of copper squares. Thus there are 25 pairs of LEDs (each in parallel) connected in series. The diodes are rated at between 2.7 and 3.5 volts forward drop, so the chain needs about 80 - 90 volts, noting that this is a "230 volt ac" floodlight where the peak ac will reach about 350 volts.
The paired diodes will give a degree of "redundancy", i.e. if one fails "open circuit", then the chain can keep working through the other; its current will be doubled, so I'm not confident about it having a good lifetime, even if it does now have a better "share" of the heatsink. The first diode failing to a "short-circuit" will probably have a better outcome, its paired LED will go out but the current will be much the same, so just a fall of around 4% in the light output. Incidentally, if you look carefully at the top-right LED in the photo that I posted in #21, it appears to have a silver strip along its left edge. That is part of the PCB pads because its either "broken" or was a smaller size. I don't know if it ever worked, but it's unlit now, although (at the moment) its partner is still working. Particularly if you have a lot of these floodlights, I think it would be worth having (say) a weekly inspection to see if any LEDs (or pairs) are "out". Easy to see from a moderate distance, perhaps with the help of a pair of sunglasses.
With the front panel / lens removed, most of the components were fairly easy to identify, because they were all marked (rather faintly to my eyes). The "tube" at mid-right is indeed a MELF resistor, marked with violet-green-gold-gold bands, does measure 7.5 ohms and the "blue blob" is a Varistor marked CVR 471K which is rated at about 400 volts, as expected (its said to have a capacitance of around 70 pF). The diode bridge is marked MB10F which is rated at 1000 volts 0.8 amp and the SMD resistor above marked 105 (1 Mohm), perhaps just to discharge any stray capacitance? The SMD chips on the left-hand side are the only unknown, their full number is CD1000AE which Google doesn't recognise, even in "any foreign language". Note that the PCB is laid out with five sets of pads, but only three chips are fitted. The connections were quite easy to identify: the incoming (negative) power goes to Leg1 (of all three chips) and to one end of each 6.2 ohm resistor just below. The other end of each resistor goes to Legs 2, 3 and 4 of its associated chip and Legs 5 - 8 are connected to the lower end of the LED string. So obviously the LEDs' current must flow into Legs 5 - 8 of all 3 chips, out of Legs 2 - 4 and through the resistors, with Leg 1 effectively monitoring the current flow, by virtue of the voltage drop across the resistor(s).
If we consider the + supply voltage rising from zero, then initially no current can flow until it reaches about 25 x 2.5 = 62.5 volts when the LEDs start to conduct, with the current rising rapidly until about 90 volts when "something has to happen". Basically, the little SMD chips need to switch off, either partially or completely: the concept of "foldback current limiting" is well-known (e.g. in dc power supplies), i.e. as the voltage across the series transistor increases, the current is reduced to keep the power dissipation in the series element to a "manageable" level. But here, the foldback would appear to need to be enormous, because the peak voltage drop across the series element is at least 200 volts, compared with perhaps 4 volts across each LED, i.e. 50 times more dissipation (as their currents must be similar)!
If there were an inductor in the circuit, then the excess voltage (energy) could be stored in its magnetic field (when the transistor is On) and then released when the transistor switches Off (i.e. a Classic Switched-Mode or Class-D power supply). I have to assume that these little chips do that with the "stray" inductance of the mains cabling (unlikely to be approved of by the Electricity Supply or Wireless Telecom Authorities). Fortunately, I have a commercial mains isolation Transformer, so can measure the input power waveforms reasonably safely, but the little DPScope can't handle asynchronous switched mode at Radio Frequencies (however, there does appear to be some "switching" during the peak period). There also appears to be a lot of "RF noise" on my mains supply, for which I haven't yet managed to locate the source.
However, I was able to record the light output, using both a LDR and a Photo-Diode (which has a much shorter time-constant). I also monitored the "real" input power level, using a commercial (Maplin) power meter. Measuring input power used to be quite difficult (needing a dual-coil meter) even with sinusoidal signals (which these certainly aren't), because of the phase shift between V and I (i.e. the "Power Factor") of any non-resistive elements. I can't be sure of the accuracy of my meter, but it's quite easy now for a microcontroller (maybe even a PICaxe) to measure the instantaneous current and voltage, several times each ms, calculate each product (instantaneous power) and accumulate an average (i.e. rms) power level. My first observation is that when the floodlight was switched on, the input power was 40 watts, i.e. a little below specification, but then fell to just under 20 watts after heating up or a few minutes. So it appears that you may not have any problems with them being brighter than the original incandescent lights (and you'll save even more money for electricity).
Here are two displays from the DPScope: the first compares the (photodiode) light detected (blue trace) with the mains voltage (red); I'm reasonably confident that the light output correlates quite well with the input current. It can be seen that the current (light output) increases rapidly about 3 ms after zero-crossing and falls back after about 4 ms, but the residual current seems excessively high, unless it's operating in a switching mode. I had expected the "unknown" chips might switch off (almost) completely during the "peak" region and then perhaps switch back on again when a "safe" level were reached on the falling side (giving a 200 Hz flicker). However, if the chips did switch off, then there would be little voltage across the LED string (unless a capacitor were also present), so the chips couldn't "know" when the voltage had returned to the safe threshold.
Finally, the second screenshot shows that the LDR (blue) has a significantly longer time constant that suppresses the initial "spike", but it still falls away quite rapidly, showing the time constant of the LDR is not particularly long. I did use a somewhat lower resistor than 100k (because I wanted to avoid saturation by the ambient light) but it didn't appear to greatly affect the time constant of the particular LDR that I was using. Therefore, it does look as if the PCBScope will be useful to measure the characteristics of your own set of floodlights, LDRs and complete system.
Cheers, Alan.