Ultrasonic Fox Deterrent


A couple of years ago, I bought two of these fox deterrents for my front lawn but they stopped working during the winter. I’d assumed that there just wasn’t enough sun to keep the internal batteries charged but, when I took a closer look this week, I discovered they both have a manufacturing fault.

The solder joint on the positive wire from the solar panel had given way – in fact it had never been soldered properly at all. The wire was held in place by little more than hot-melt glue. The connection on the solar panel itself seems to have some sort of nickel-plating and refused all attempts to take solder to reconnect the wire properly.

Normally, connections to this type of metal are made using a cold welding process but the blob of solder on the wire showed the manufacturer had tried to use ordinary tin/lead or lead free solder

I was able to make a quick and dirty repair by cleaning off the hot-melt glue from around the connection and slipping a piece of thin metal between the top of the enclosure and the underside of the solar panel. I’ve hopefully held it in place with a blob of Araldite.

The third photo below shows one unit now charging away (as shown by the blue LED) and the second unit just waiting for the Araldite to harden before reassembling it.

You may also have spotted in the bottom photo that, although the exterior of the units give the impression they have two ultrasonic sounders, one is just a dummy and they do, in fact, only have one!

Making Candles!

DSL/Broadband Router Watchdog


Finally got round to writing up my latest Arduino project and posting it on my main site.


BaoFeng UV-5R Tranceiver


A friend recently sent me a link to this little gem of a transceiver on eBay. Although it’s been around for quite some time, it was new to me and, for the amazingly low price of £19, it was too good to miss. When you consider that the established manufacturers of amateur radio equipment would be asking anything from around £150 to £200 for a similar dual-bander, I wasn’t expecting much.

But I was wrong! It looks and feels every bit as good as its expensive counterparts. Apparently, the audio quality is good – although I haven’t tested it myself yet – but it is a bit tricky to set up with your favourite 2m and 70cm amateur band channels. Like everything, though, once you get the hang of it, it’s quite straightforward.

For my own reference as much as anyone else’s, here’s a quick cheat sheet:

Programming the Baofeng UV-5R Radio

Common ("Global") Settings:
These settings can be set on a "per-channel" basis in Memory Channel mode but the last settings will persist across Simplex Channels and Frequency Mode. The repeater offset setting (#26) may be left at the last setting provided that the Repeater Shift Direction (#25) is set to OFF.

(a) MENU -> #13 for Transmit CTCSS. MENU-> CTCSS frequency (eg: 110.9Hz). MENU to confirm
(b) #25 for repeater shift direction: -, + or OFF. MENU to confirm. (- for 2m. + for 70cms).
(c) #26 for repeater offset: 000.600 for 2m or 001.600 for 70cms or OFF for Simplex. MENU to confirm.
(d) #27 to select a memory channel to program. MENU -> #27. MENU to confirm.
(e) EXIT.

Repeater channels:

You can get a list of repeater settings (INPUT and OUTPUT frequencies, CTCSS frequency, Offset frequency and Shift Direction) here: ukrepeater.net.

There's no point programming the Repeater Offset or the Repeater Offset Direction because both Input and Output repeater frequencies are saved in the memory channel anyway.

(a) VFO/MR -- set to Frequency mode and type in repeater OUTPUT frequency (Our radio's RX frequency).
(b) Press MENU -> #13 -> MENU. Select CTCSS frequency (eg: 110.9Hz). MENU to confirm.
(c) #27 for memory channel -> MENU -> type channel number. -> MENU to confirm.
(d) EXIT
(e) Check still in Frequency mode. (VFO/MR).
(f) Type the repeater INPUT frequency (Our radio's TX frequency).
(g) MENU -> #27 -> MENU -> Select same memory channel as (e) -> MENU to confirm. EXIT.

Simplex Channels:
(a) MENU -> #13 -> MENU -> OFF (Transmit CTCSS to OFF) -> MENU. EXIT.
(b) MENU -> #25 -> MENU -> OFF (Repeater Shift Direction to OFF) -> MENU. EXIT.
(c) VFO/MR -- set to Frequency mode and type simplex frequency.
(d) MENU -> #27 -> MENU. Type Channel Number. MENU. EXIT.
(e) Still in Frequency mode so -> Type next simplex frequency (or use up/down arrows).
(f) MENU -> {* #27 ->} MENU. Type Channel Number (or use up/down arrows). MENU. EXIT.
(g) Repeat (e) and (f) to store other frequencies in memory channels.

* Menu is still in Memory Channel Number sub-menu so no need to type #27 after first time.

Audio Sinewave Generator

Probably my last project until the darker nights are upon us again.

Full details on my website: XR-2206 5Hz to 300kHz Function Generator


In July last year, I posted about a dashcam I’d fitted to the car.. well, the GPS unit packed up last week. Also, the connections on the mounting bracket (which were always a bit suspect) had got worse so I decided it was time for a new dashcam.

Unfortunately, of necessity, these cameras operate in what must be one of the worst environments possible for a bit of domestic electronics – stuck at the top of the windscreen in the full glare and heat of the sun (if we’re lucky) so I guess 18 months is a reasonable time for them to last – especially for low to mid-priced units such as the E-Prance 0803.

So, I ordered one of these. I don’t know if mine was faulty but the GPS unit wasn’t working and it wouldn’t remember any of the settings I’d configured. So, back it went for a full refund.

I’ve now ordered the latest version of the E-Prance camera – the 0806. So far, it seems to be working as expected (although it’s not fitted in the car as yet).

I thought it would be interesting (to me anyway) to open up the old E-Prance 0803 because I wanted to disconnect the defunct GPS unit internally and I wanted to see what exactly was used as the standby power supply. From the very short time the standby supply lasted, my guess was that it used a super-capacitor.

Click the pics for a larger version.



I was surprised to find that it uses a fairly large lithium-polymer battery rated at 400mAh. Presumably it was another victim of the excessively high temperature inside the unit as it didn’t really hold any meaningful charge at all.

Other than that, I was actually quite impressed at the overall quality of the camera’s construction. Two double-sided PCBs mated with three high-quality miniature two-row header plugs and sockets.

The latest model has addressed the overheating issue (basically by drilling loads of holes in the case) so, hopefully, it will last at least as long as the old one.

The old one is now re-assembled (and working!) so I intend to install it in the rear windscreen to see if it will deter the bane of my life – tailgaters!

New Project


FM Transmitter for Car MP3 Player

Another PayPal Scam

Received an email this morning supposedly from PayPal. You can usually tell scams and phishing emails by the bad grammar and poor spelling but this one was almost perfect (click image to enlarge):


I could almost have fallen for this one – until I saw the Subject header! 🙂


9/10 better luck next time ! 🙂

Scams, phishing and hacking…

With the recent hacking of the Talk Talk customer servers, the news media is busy wheeling out the usual so-called internet security experts offering the usual post apocalypse advice.

One sentence from Talk Talk is particularly enlightening: ” At this stage, we’re not sure how many of our current and previous customers have been affected.”

One piece of advice that makes sense on the face of it is to close any account as soon as you finish doing business with any company. In truth this is easier said than done:

“Some time ago,” I closed a certain mobile account because I found their coverage too be poor where I then lived. A few months later, I was surprised to find I could still login to the account and see that the small remaining balance had been, er, “siphoned up” by the company’s “timeout policy”. After looking for a “Delete Account” button and not finding one, I phoned customer services and was promised the account would be deleted properly- not just closed.

Some, 12 years later, having moved home and switched back to the same company, I decided to set up another account but was refused because the same username and password were already in use. So, although my old account was no longer accessible via the customer’s user-interface, it turns out all my financial and personal ID data had been held by the company “just in case”.

Now, I can see how they can justify holding onto your details for a month or two as a convenience so you don’t have to enter all your personal details again, should you have a change of mind, but 12 YEARS??!

I can’t help wondering how many other “closed” accounts I have gathering cobwebs with companies I no longer deal with and may have long since forgotten about but which are rich pickings for the hackers and scammers.

It makes a mockery of the advice to “close accounts of companies you no longer deal with” and, in any event, it’s virtually impossible to know if an account has in fact been deleted if even the company’s own support staff can’t do it.

Maybe the law should be changed forcing companies to actually delete closed accounts and not jut squirrel them away “just in case.”

PayPal Phishing Scam

Just had this email supposedly from PayPal. The URL of the webpage you’re invited to visit looks quite like the genuine PayPal URL and the page looks pretty much identical… One to watch out for.

(Click for larger image)