Build it on a plug-in solderless breadboard and get a sense of it before you even start soldering

That is my first step with many circuits, including ones where i am really pushing the breadboard limits (switching power supply on a breadboard is significantly affected by stray capacitance, but still useful to weed out all sorts of overlooks and errors, and get sense of component values beyond the initial estimation/calculation)



The capacitors are mostly <1uF ceramic (use Kemet Goldmax series). They are small and flat (you can fit them side by side at 0.1" spacing, at least as long as you dont put 1uF or more in there), except the 10uF one which is a little cube (would fit in 0.2" space)

Some ceramic capacitors have 0.1" and some 0.2" lead spacing. See what's available where you get them

The 10uF is the only one which you are likely to switch to an electrolytic, like if you want to put something of higher capacity in there, or due to cost (an electrolytic probably cost less than 10uF ceramic), though it may have a little higher leakage. Placing 2 parallel spots for ceramic capacitors is also an option




What you have drawn is well within the capabilities of all PCB manufacturers and even low tech PCB manufacturing, but here is a consideration about leakage currents :

The high resistor values (chosen to save battery) mean that the circuit is sensitive to leakages from contamination/dampness. Specifically the networks connected to high impedances : Pins 2, 6, 5 of both 555's, link between D3 and R6, Gate of output MOSFET

Avoid making those traces large or shoving them in tight spaces if possible (where little contamination on the board surface may make a significant resistive leakage between them and something else)

For the final production, go for a board with solder mask to isolate most of the trace surface, and protect it with conformal coating if needed



DRC is a useful tool, but it does not tell the whole story

DRC (in its most basic form) just verifies that you keep the minimum set distance between traces, an other distance-based rules

Here we are talking about contamination, essentially a parasitic film resistor. Obviously, the width of the film (length of parallel traces) will affect the resistance just as much as length of the current path (distance between parallel traces). DRC does not say anything about trace length. It is up to you to design in a sensible way

Even when it is about voltages and flashover distances (typical use case of DRC), electrical breakdown is a statistical effect. If the safe distance for a certain voltage is 3.0mm (for example), a board filled with comb pattern of traces spaced at 3.0mm (pefrectly ok according to DRC), will be much less reliable and less safe than a board with reasonable design, where in one spot the distance is 2.95 (which will make the DRC flag it)

And then there are all the additional considerations : Is it about distance between 2 open solder joints ? Is it between 2 traces, both insulated by solder mask ? A solder joint and a trace ? etc



I would recommend leaving an option for assymetrical duty cycle of the fast flicker for further experimenting (add place for a diode and resistor like D3+R6 in the 2nd 555)



If you want the Kicad file just ask. (Also, i highly recommend Kicad in general both for circut drawing and PCB design, it's my main tool - Along with Qelectrotech for electrical wiring drawings)

There was also one detail: Pholops had in their offerings "emergency light" F6T5 (dunno the exact marking), especially designed to run on the battery inverters which tend to underdrive the lamps and so makes them suffer for cathode sputtering. It had thinner, lower current filaments, plus maybe few other modifications to run better at the reduced power ballasts.

I see you have very small clearances at a few places, which will likely lead to short circuits.
Learn to set up and really use DRC (Design Rule Check) function of the CAD software you are using on your designs and rigorously clear all real violations.
With the rules don't push the manufacturing (that includes your ability to solder things without shorts) to the limits by e.g. allowing smalled clearances or distances, it will bite you into your rear later...

Israel. Here situation is a bit different both in terms of circuitry/technology and equipment ownership, but still may make sense for your question

The utility company (IEC) owns and maintains the electrical grid and provides the power, and local councils own and maintain the lighting. The lighting can be installed on the electrical grid poles, or on stand alone poles with feed from underground

The low voltage grid is powered from high power 3 phase transformers, typically 400kVA and up (even when they are powering much lower actual loads). In suburb-like areas with single family houses, such transformer powers a long stretch of low voltage grid, that can supply many 10's of houses

Lighting is virtually always group switched, there are no photocells on the lanterns (with the exception of some very new LED installs that need to be permanently powered for some "smart" system built into them to work, which more often than not results in dayburning lanterns, which negate any actual energy savings from said system...). The central control location may have a single photocell mounted on the cabinet, but sometimes they are only on a time switch (in the old days) and sometimes a wirelessly controlled switch (in some mew systems)

Consider a low voltage power line going along a suburb road. This power line carries typically 6 conductors, either as bare wires on insulators, or as a twisted bundle of insulated single wires called ABC. The conductors are :

Phase 1
Phase 2
Phase 3
Neutral
Lighting phase 1
Lighting phase 2

The Lighting Phases are switched on or off by a contactor, usually in a cabinet that stands on the ground near the beginning point of the grid (a cable on the nearest pole goes down to feed the cabinet, and anoter cable goes back up to connect the switched phases to the overhead). This cabinet contains a kWh meter, so the energy use of the lighting is metered and billed exactly (the council pays the utility company)

A house is connected to a phase (or all 3 phases) and neutral, either by an overhead service drop, or a cable going to the ground from the nearest pole and connected as from underground service (standard since 80s and later)

A lantern on the pole is connected to one lighting phase and the neutral. In some setups one lighting phase is powered part night and one full night, allowing lanterns to be connected in alternating order to one or the other. In the 70s and 80s lanterns with 2 lamps made appearance in towns, sometimes wired such that the 2 lamps in the same lantern are powered from the 2 different phases

(I am not sure why 2 lighting phases, but i guess the main reason is to keep an even number of wires, so they can be symmetrically arranged on 3 cross arms. I guess that the overhead line going from the control point might have different phases going in different directions, ie. if the grid goes from there in 3 directions, then they will get L1L2, L2L3, L3L1 as the 2 lighting phases, keeping the collective load more or less balanced)

When the utility company change a pole etc, they usually move the existing arm and lantern to the new pole and reconnect it, or if they deem it unnecessary, then remove it altogether, but looks like they still return it to the council. Once i asked for such lantern that was taken down and they said they must take it. (Interestingly, the other lantern on the same pole they did move to the new pole and connect, including a fully black leaked SON lamp in it. Many years later in an unrelated occasion, this lantern ended up in my collection, still with the same EOL lamp)

Lighting-only poles powered from underground, as well as the cable feeding them are fully council owned, so there the utility company is unrelated

Working on the board layout for @Ash 's circuit. I will likely mess with it on a small prototype board before ordering in an actual board. The circuit as of this moment in time will only be used in two flashers so I don't think I can justify the cost of ordering in custom boards... however If I start replacing controller boards in other lights. perhaps it might be worth while to evolve from proto-boards to real... who knows what the future holds.

this mock up is not done yet. I am sure I made a mistake somewhere I will find later. I am not well rested lol.

Consider that with the push to lower the Mercury content, the lamps do contain less Mercury..

The absolute longest i seen were on the road up from my house. Those were some 250W SON-T from unknown manufacturer, original first lamps installed in Hubbell RMG lanterns with 230V 50Hz gear, from the late 80s

Most of those lamps lasted well into the 10's (everything was replaced with LEDs in the 10's)

Some lamps would warm up to fairly bright clear Mercury light and stay at it for a good 10 minutes or more before continuing to Sodium color. One of them was occasionally cycling in the later years, it could cycle one night and remain stable for many more nights in a row. The off periods were very long (to the extent unusual even for MH), the restrike was directly from nothing at all to the clear Mercury color, no glow and often no flashes before the restrike

Back in 2022 i have bought a 90's car in fairly good condition for a 2nd car / restoration project (which is more than half done, but now stalled first due to war. and later due to lack of time). From a trade in. This had been probably a once in a decade find if not rarer, most cars traded in/out are from the last few years, and most 90s cars to be found on 2nd hand trade lists are nowhere near such condition or even a similar car type

It does not show luminescence, it goes dark instantly when you turn it off.

The spectrum does not show any more UVA than other fluorescent lamps, so it is not specially designed to make dayglo pigments light up. The only reason why 'emergency use only' is printed on it, is because fluorescents here are still allowed to be made for use in emergency lighting fixtures.

If only we had a Philips engineer here who could chime in why that specific phosphor was added to a very cheap lamp, close to the end of that technology being produced at all.

Yes, especially since in Florida, most native vehicles avoid rusting, so I’m looking for a low mileage example that spent its time here. Plenty around, but the chances of one getting traded in, or finding one come for sale is unlikely.

That is a good call