Automatic Voltage Sensing Car Auxiliary Socket


There are many devices which are designed to plug into a car’s auxiliary socket (formerly known as the cigarette lighter socket) which, ideally, depend upon the voltage turning off with the ignition. One such device, which I’ve recently fitted to my own car, is a dashcam. Luckily, the power to my car’s auxiliary socket is switched with the ignition but there are a lot of cars in which the power isn’t switched with the ignition.

I’ve spotted one or two dashcams which can automatically sense if the engine is running but they tend to be very top of the range devices costing £150++. For the rest of us, it’s inconvenient to keep plugging in and un-plugging the dashcam’s power lead at the start and end of each journey (or fitting some sort of switch) and, in any event, is likely to be forgotten just when it’s needed!

This project is designed to monitor the battery’s voltage to determine whether the engine is running or not. It plugs into the auxiliary socket at the “front end” and has it’s own switched auxiliary socket at the “rear end”. I’ve only been able to find one commercially-available product which does the same and, in my opinion, it seems a bit expensive. Depending on what you already have in your spares box, this project should cost about a third of its commercial counterpart.

Details on my main site:

Another HVDC Cable boat shot.


and a photo sent by my bro…


Takes all sorts.

What with speed humps, potholes, dog walkers, pedestrians, cyclists and the fact there’s no pavements, I would have thought that 20mph was plenty down this narrow lane. But, hey, what do I know….

Rechargeable Lithium Battery Capacity Tester

Finally written up the details of my rechargeable lithium battery tester and put the info on my main site for anyone interested.


Some more HVDC photos.

Lovely day and evening. Finally tempted me out at night!

(As always, click a photo for a larger version – and click again for even larger!)

300mm lens. Night shots: 1/2 second f16





HVDC Cable



Back to it!

With one thing and another, my rechargeable battery tester project has taken a bit of a back seat since the parts arrived two weeks ago.


I needed to spend some time tidying the garden now that the plants are starting to die back and then the computer decided not to behave. Everything tested out ok, but tests on the memory and hard drives tend to be time consuming so it was a case of nipping in and out to sort the garden and the PC at the same time.

I’ve come to the conclusion that the computer’s main hard drive is on its way out so I’ve replaced it with a spare. Trying to rush things, I was installing Windows updates at the same time as I was installing other software and that didn’t go at all well. All in all, it’s taken about four days to get the PC back to how I like it. So…. back to the battery tester project!

I’d already designed the PCB before the other jobs interrupted me so, hopefully, I’ll be able to make some progress now before I get bored with it. I’ve just finished etching the PCB so now to the fun job of drilling all the little holes!


I contacted the Council about a bit of fly-tipping that I’d spotted about three days ago. It’ll be interesting to see how quickly they respond… or not.



The Council are having another discussion about the closure of Lyndale Special School tonight, the ruling Labour cabinet’s original decision to close it having been “called-in” (ie challenged) by pretty-well most of the opposition.

According to the Globe, the Education Secretary is “taking an interest” (whatever that means) so the Globe will make an interesting read tomorrow – although, knowing this Council, nothing will change.

Can’t win!

If it’s not the cats, it’s the magpies!


Welcome to the Wirral Dictatorship

Voice of the Globe: Lyndale families sold down the river

Let’s be honest. This Council has connived and manoeuvred themselves into an unassailable position over the last few local elections and then by manipulating the structure of the Council itself.

Nobody in their right mind could believe that every single Labour councillor thought this was the right decision – yet it passed unanimously. The same as every other decision this Council makes. When individual councillors are unable or unwilling to cast a free vote, in my book, that’s the definition of a Dictatorship.

And make no mistake, they know exactly which part of the electorate they can ignore and which part they need to keep sweet with subsidies and benefits in order to ensure they’re voted into a majority again next time.

Moan about this Council all we like, nothing short of – somehow – getting Central Government to intervene in this totally corrupt and rotten borough will change anything.

2.4 GHz Spectrum Analyser – Update

Finally finished the write-up for my Spectrum Analyser and put it on my main site:

Spectrum Analyser