Introduction:

It is probably fair to say that just about every man and his dog has heard of so-called 'PIC' chips by now. We know that they're widely used these days - from space rockets to toy games to house-hold appliances - and we also know that a PIC is a miniture computer crammed inside a tiny package. But how many of us know what goes on inside? And why do electronic designers think of PICs as the best thing since sliced bread?
Taking the second question first, the answer is relatively simple: in a nutshell, it's a hardware thing. For instance, imagine a complex traffic light system where each Red, Amber and Green has to work in a particular sequence. The designer is left with the task of ensuring he gets things right. So, before the advent of PICs, his circuit board would have employed hundreds of transistors, logic chips and so-forth. This meant a lot of real estate was needed to house all those transistors, etc (read £££). And if he should get it wrong, a bad PCB would have meant the sequence of lights would have been up the spout - along with his reputation. But then the Programmable Interface Controller came along and Mr. Designer was soon able to minimize his circuit board. He could omit all those decision-making logic chips and such-like, and now design an altogether less-complex circuit.

In simple speak, it was now possible to connect his Reds, Ambers and Greens directly to the PIC instead of worrying that his design might end up with, say, a circuit track in the wrong place, or a misplaced component. Best of all, since the hardware problem was virtually no more, all he had to do was write a program, then let the PIC take care of the business.
And if by some quirk of fate the engineer on the street had inadvertantly cross-connected the Red, Green or Ambers, then the problem could now be solved simply by adjusting the program code accordingly... which is far easier than digging up the streets again and re-wiring the lighting circuits - or designing a new circuit board from scratch.

The low-down:

Since the software program takes care of the hard work, which in turn greatly simplifies the PCB hardware, it means you are pretty much guaranteed the unit to work right from the moment you connect the battery.
Of the myriad in-built features, one in particular which grabs your attention is the ability to test the pulse timing of R/C transmitters. This is nice, because now we have a visual indication of the exact pulse value clearly shown on the 21-digit LED display. For those who like to tinker, this unit takes all the guesswork out of setting up and/or re-alignment of the Tx sticks.

Each time the unit is powered up the center LED only is on, which denotes an exact 1.5 milli-second pulse (equating to the servo being at dead center). This neat feature makes alignment of Tx gimbals and servo horns simplicity itself.

Switch S1 set to Auto-scan mode sweeps the servo through 170-degrees without nery a glitch nor judder, delivering silky-smooth PIC-controlled pulses all the way from 1.0 milli-second to 2.0 milli-seconds.

So what do you get for your money?

In a word - quality. Not only does ACTion provide an excellent delivery and backup service, they also provide top-notch components. For instance, the PCB is of the highest quality glass fibre. Each hole is perfectly drilled, with not even as much a stray fibre anywhere (unlike some kits I've seen).

As well as the super-slinky on-board slide switch (mode select), another nice touch worthy of mention is the wire links. This particular kit requires four links on the PCB, and even those haven't been overlooked, because 4 x zero-ohm resistors are included instead of plain old wire. It's the little things like that which affords us a sneak insight into what's going on behind the scenes of the ACTion camp. No corners have been cut, which means that building these kits is an absolute joy.

Starting out:

A quick inventory shows that everything is there... even down to the last nut, bolt and washer. A plastic enclosure is also included, along with a self-adhesive front-panel decal. Furthermore, ACTion have also included a full-size template with all the dimensions showing exactly where to drill the enclosure for each hole and each cut-out.

Talk with the nice man on the telephone and here's what you get £25.00 later...

Construction:

The components don't have to be installed in any particular order, so I opted to solder all the resistors first. Photo #2 show those four zero-ohm links mentioned earlier. But what are those four oblong-shaped orange blobs there? Those too are also resistors. Known as Single In-Line (SIL) devices, they do in fact, in this case, each contain five separate 470-ohm resistors. Their job is to the limit the current to each of the 20 LED segments.

So compare the physical size of each single resistor to that of the SIL's. Now imagine how much more board space would be needed should the SILs be replaced with 20 individual resistors.
Now you REALLY start to get a feel for how the designers at ACTion operate.

Slight deviation #1:

I had already decided right from the off that I didn't want this unit enclosed in the supplied ABS case. This means I deviated slightly from the recommended construction by utilising two 3-pin servo connectors at the input and output. (ACTion suggest you use a servo extension lead and route the wires through a cut-out in the enclosure). This board is too nice to hide away, so I opted for the on-board connector idea instead. The only downside to doing it that way meant I had to flip the board over a couple times to grok the PCB traces in order to remember which pin was positive, negative and signal.
Since this photo was taken I've now heeded ACTion's original fly-lead suggestion because...

1. It's easier to get the polarity right when connecting the battery and servo, and...
2. The female/male connectors from a servo extension means it's easier to tell which lead is input and which is output.

ACTion kits are obviously designed that even Mr. Average would have no problem with construction, and as long as you follow the instructions it will (does) work right off the bat... first time. But just to recap what is already emphasised in the instruction sheets, do bear in mind that the semiconductor devices are polarised and should be inserted with the correct orientation. Note also that, although they are not semi-conductors, the two pushbutton switches also have to be oriented correctly. A 'flat' is shown on the construction pages, which tallies with a flat on the side of each switch itself.
Photo #3 isn't too clear, but if you squint you can just make out those flats, both facing towards the slide switch.

Slight deviation #2:

If you intend fixing the unit inside the supplied enclosure, then you will have to use the aforementioned pushbuttons. In my case, I figured it would be just a matter of time before one or both got broken. I had that exact thing happen already, with the exact same type of pushbutton on a somewhat expensive frequency counter, and back then it wasn't so easy to get replacements. In other words, they're fragile if not used with the enclosure - hence the reason I swapped them out for low-profile tactiles.

Also, I didn't realise until the moment of power-up that the 10-digit displays were of the green variety. For some reason I was assuming red displays. Photo #4 now shows the centre LED swapped from the supplied red to a green flavour.
No particular reason for doing this other than one of personal preference.

The fun part:

Since this is a true plug & play unit, what can be easier than connecting a battery, a servo and pressing a couple buttons? You'll notice as soon as power is applied the center LED will be on. The P59 will now be in manual mode, pumping out dead-accurate 1.5mS signals to the servo. Don't press those buttons just yet, because now is the good time to align those servo horns.
Real men would have pressed those pushbuttons already, in which case would have noticed the servo advancing or retarding either side of neutral. Four presses of either button equates to the display incrementing or decrementing by one segment.
Auto-scan is another variation of manual mode, only this time the servo repeatedly sweeps from left to right without having to press anything. This is an excellent feature, particularly useful for running-in new motors.
The photos below show the actual signal which the servo sees. Oscilloscope timebase is 1mS per division; amplitude is five volts.

Some of my servos exhibit a slight judder. Why?

This is where the p59 really shines, because it merely highlights the limitation of some particular servos. What actually constitutes a good servo is usually made up of many factors. e.g: the number of poles on the motor, the gearing, the bearings, etc, etc....
The buzzword here is resolution. Higher resolution means a better-quality servo, which, in turn, means no judder. The P59 excells in sorting the men from the boys.

Parting comments:

Even though I have only hinted on its abilities, ACTion-Electronics have given the R/C fraternity a world-class winner with their P59. On the strength of this wondrous gizmo I would have absolutely no reservations in recommending this fine and friendly British company to customers old and new alike.

A hearty glass of finest apple juice is raised to their continued success.