Saturday, 26 May 2012

Frogs, rollers and don’t you love eBay!

But first, here is a good reason for not being in the workshop much this week! this was 10 o'clock tonight!

More frog...

Having stripped the guts from the frog there were still two wires connected to the Light Dependent Resistor (LDR) fitted in to the mouth of the frog. A quick snip with side cutters and the whole lot is free. The black mount/shield is easily prised from the frog’s mouth. The intention is to build this silly little bit of electronic fun, as it is, into a model at a later date to entertain the kids.

The little circuit board has a few through-wired components and a black-blob that covers the naked IC providing the timing and ‘croak’. This is a common method of mass-producing cheap circuitry for all sorts of gimmicky gifts and novelties such as this and musical greetings cards etc.  I also found the same method being used on the circuit board in a pound-shop USB hub that I was dismantling for the bits. I must admit at the time I was not at all sure what these black blobs were as I am only now reviving my interest in electronics. Having not built anything electronic for over 20 years, until recently, I have a bit of catching up to do. A post on the EEV Blog forum regarding these black blobs soon returned some sound answers and some other interesting facts that have got me thinking. Some of the flickering light novelties utilise the musical greetings card electronics to power LEDs instead of miniature speakers rendering a rhythmic but apparently random flashing. I wonder what croaking frog would look like?

Plate bending rollers

Rolling bars are screwed down when in use
Now look here people, you are supposed to be looking at what I am showing you in the pictures that accompany my ramblings, NOT LOOKING AT WHAT IS LAYING ABOUT ON THE BENCH!! I have received several e-mails asking about the sheet rollers mounted to the bench while I was bending the Meccano to build the crown for the Chelsea Flower Show exhibit. They were purchased from a chap who was selling them on e-bay a couple of years ago. Unfortunately I could not find them when I looked tonight. I think he may just make a batch and list them intermittently. If you do find a listing let me know and I will post a link. Bending the longer, heavier gauge, perforated Meccano strips proved a bit much for my Meccano built bender. You will find some more information on Meccano built bending machines on our Meccano website HERE.


Love it or hate it eBay is a fact of life and if you play nicely it can be a very useful tool. If you need a particular part or a left-handed what’s-it to fit a 1935 widget there is a good chance that someone will have one for sale. If you are selling the afore mentioned what’s-it, there is bound to be some one who wants to buy it. OK, you do get the odd idiot but they are fewer than the stories will have you think.

This week has been a case in point. I was looking for a middle of the range (sorry about the pun) auto/manual ranging digital multimeter with a micro-amp range. Spending three figures on meters is restricted to work. I can’t justify spending Fluke-like prices on something that is a hobby tool and is never going to pay its way. So. There I was skipping through the listings on eBay and there on a buy-it-now listing was a Extech 430 for £14.95. Halfway through a double take and I hit the ‘BUY’ button – Result!

The meter had only been listed a few minutes earlier and for once I was in the right place at the right time. A couple of days later and the postie was knocking on the door. Grubby and looking used it was looking a bit sorry for itself but it was working and had a battery with a full charge. While Sue set to work with the good old kitchen cleaner and MR Muscle bathroom cleaner (wonderful stuff) I got to work with the screwdriver and took it to bits (as you do!) to get at the clear plastic LCD display cover. This was badly scratched and just generally grubby. Liberal application of Auto-Sol chrome cleaner cleaned off all the dirt, polished out the light scratches and cleaned up the deeper scratches making them far less obvious.

Stripping the meter gave all the connections between the plug together boards a workout and subsequently improved the sound of the continuity tone. Great value for money, a decent meter for less than the price of a round of drinks!



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