In the UK at least, formal electronics courses for mature students are getting harder to locate. The Open University used to be a great source of these courses in years past, but alas, no more.

However, my interest was peeked when I saw that MIT (Massachusetts institute of technology) in the USA are offering a FREE on-line “Circuits and Electronics” course. The course is completely virtual and open to anyone from any country. All course materials and even virtual laboratories will be provided.  

The nice thing about this idea, aside from the fact that it’s completely free of any costs to the student, is that you stand to gain a certificate of completion from a very well known and prestigious university.

You can find more details here: http://mitx.mit.edu/

The course starts March 5th 2012 and runs for approximately three months.

The only snag for some people may be the requirements:
"In order to succeed in this course, you must have taken an AP level physics course in electricity and magnetism. You must know basic calculus and linear algebra and have some background in differential equations. Since more advanced mathematics will not show up until the second half of the course, the first half of the course will include an optional remedial differential equations component for those who need it.
The course web site was developed and tested primarily with Google Chrome. We support current versions of Mozilla Firefox as well. The video player is designed to work with Flash. While we provide a partial non-Flash fallback for the video, as well as partial support for Internet Explorer, other browsers, and tablets, portions of the functionality will be unavailable."

However, since it’s free, what have you got to loose.

I’m on the hunt for a new multi-meter. I’ve got several already, ranging from cheap and cheerful that I leave in the boot of the car for emergencies, to small, portable with additional features for environment monitoring like temperature and sound levels that I carry around in my rucksack, and some more typical larger units for workshop use. The other day on a whim, I got them all together and decided to see how accurate they were. I set my PSU to 12v DC, and one by one used each one to measure the measure the output voltage.  I started with my Thurlby Tandor bench multi-meter and left that one connected thought the test to monitor the output of the PSU in case it started to drift.

Every meter gave slightly different reading. They weren’t out by much, but it did get my thinking that it was time I invested in a reasonable quality one that was calibrated for bench use.

So, I went to EBay initially to have a hunt around to see what new equipment was available. I stumbled across a make I’m not familiar with, Uni-Trend. I’ve been seeing a lot of their equipment around recently and I found a rather nice unit – UT803 available in the UK for 104.95 GBP including VAT and delivery. On further inspection I found that it’s actually being sold by Rapid Electronics; this is why the make seemed familiar as I’d probably seen it on their site previously.

Annoyingly, the UT803 is listed on the Rapid main site, but it costs 114.07 GPB  including VAT and you’d get free delivery on that order as it’s over £30.

The Fluke 5211 from Rapid’s site is £246, but their Ebay shop sells it for £279.

I was displeased to see many other differing prices for Rapids offerings.

They have some 3.3v MES bulbs that are 100% more expensive on Ebay, but some hand tools that are cheaper, and the discrepancies go on and on.

MPLAB ICD2 Ebay - £154.95, Main shop - £150.50

Pack of 100 resistors - Ebay £0.99 - Mian shop - £0.62

The  ST Mems Sensor Evaluation Kit (82-1004) which is 79.50 on Rapid’s site, is only £38.99 from their Ebay shop.

You’ve really got to check both places now if your after the best prices from them. Also, delivery charges for orders under £30 from their main site attract a £5 + VAT delivery charge. The charges from their Ebay shops are much more reasonable.

If you find an item in their Ebay shop your intersted in, at the end of the product description is a numeric code. Just enter this code into the search on their main site and it will find the same product for you making it faster to do the price comparisons.

Wire strippers that is... sorry chaps...

Good tools are expensive and a decent pair of wire strippers can set you back a kings ransom, and by decent I mean a pair that you can use with one hand, will just grab the end of the cable and strip without too much pre-adjustment, not damage the metal inner conductor, and work pretty much every time.

If you want to find out just how much a pair can cost, checkout some of the bigger suppliers like RS and Farnell.

Well, all is not bad news. Rapid Electronics have some Abeco Micro Strippers on offer (Part number 86-0325) for less than £20 including VAT. I’ve had an identical pair of these for a while now (and paid a heck of a lot more for them at the time) and they are perfect for Hobby Electronics. They are a little bit smaller than the standard full size pairs which makes them ideal for use in tight spaces. They will happily work with common 10/0.1 stranded hook up cable and the 1/0.6 solid core preferred by breadboard users. They will of course also work with larger gauge wire as well.

They are supplied in a little plastic case, with three pairs of gripping pads and a small adjustment screw-driver.

I would suggest if you don’t have a decent pair or wire strippers (or your just looking for a second pair), whilst they are available at this bargain price you invest. My larger pair that I’ve used almost every day for 15+ years are still going strong.

Here’s the technical blurb:
·         Self adjusting over the full range
·         Small enough for closely packed assemblies
·         One hand operation allows use over long periods without discomfort
·         Incorporates a cutter which will cut wires up to a maximum of 1.5mm²
·         Supplied with three pairs of differently serrated gripping pads to suit various insulation materials without damage
·         Replacement jaws available
·         Weight 76g
·         Dimensions 155 x 80 x 14mm

http://www.rapidonline.com/Tools-Equipment/Microstrip-self-adjusting-wire-stripper-30552

Now I’m not in any way connected with Rapid Electronics in the UK, but I really do like using their services. If you order before around 8pm they usually deliver next day, and whilst I do wish their product range was a little larger in some areas, you can usually find what you need (or often an acceptable equivalent) and their prices are usually some of the best. As always when shopping, it pays to look around of course.

You can also be sure that their stock is genuine and non of this fake or out of spec rubbish that you can sometimes get landed with off auction sites.

I’ve just been looking on their site this morning, putting together my next order and they have some real bargains right now. I’ve listed a few below that caught my eye.

47-3302   L78S05CV +5v 2amp regulators at 20p each (normally they are 56p)
You can use these as a direct replacement for the usually cheaper 1 amp versions.

78-0206   16 key waterproof keypads at 3.15 each.  
Just because it’s waterproof doesn’t stop you using it indoors.

22-2431   15-way 90 degree pin headers (like molex connectors) for around 7p each, and 22-2432 16-way  versions for 11p each. These are ideal for cannibalising for their 90degree pins. You can then use these pins to convert smaller way connectors into 90degree versions. This means you don't need to buy seperate striaght and the more expensive 90 degree variants. The 16 way ones are also great for soldering to LCD displays as well.

77-0142   26-way right angle PCB mount hi-density D-type plugs. These are great for those projects that need a nice compact hi-density connector on the front. And they are only around 2p each.

They also have loads of stuff in their clearance section that’s worth a search.

I’ve blogged about wire cutters previously and why I only ever buy cheap pairs. Old pairs are often kept as they always come in handy for silly jobs.

At the weekend I used an old pair to try and break into some plastic gizmo; I didn’t really care on the damage to the thing… I just wanted to see what was inside.

I've done some silly things in my time, but I've never had a pair of cutters split like this on me.

Because a lot of people have asked me about PIC programming using the AMICUS18 BASIC compiler and how to do things, I thought it would be interesting and useful if I wrote a series of articles on the subject (see here).

So, to kick things off I’ve placed the first three on this website. I’ve never done anything like this before so please let me know what you think or if there are any topics you would specifically like me to cover.

I’ll be adding more parts on an on-going basis.

You can find the dedicated page here:

I've added a new construction project for a plug-in PCB module for breadboards.
It allows one of those cheap and nasty plug-in mains transformer type PSU to be used as the power source for a +5v regulated PSU thats suitable for powering PIC, TTL/CMOS logic and other circuits.
Because there's no direct electrical connection to the mains, it's perfectly safe for beginners to create. You can also throw one of these together for less than £2.00

If anybody in the UK is interested, I've got a couple of blank, etched and drilled PCBs that I'll give away on a first come, first served bases. All I ask is for £1.00 to cover my postage and packing costs. All you need to find are the 13 components to assemble the thing.

Been really busy over the last few days with a lot going on.

I’ve started writing a series of articles on programming PICs with the AMICUS18 PIC BASIC compiler from Crownhill Associates. Each article covers a specific topic starting with how to get everything configured and writing your first “Hello World” BASIC program,  and then onto interfacing to common electronic components. Each article includes circuit diagrams and source code.

I’ve also added a review on a new toy… I mean tool, for the bench; a Weller gas powered soldering iron which recently arrived from Rapid Electronics.

Now I love clocks, I really do. They are great projects because you can place them on the mantelpiece or in other prominent locations as a functional working device, partners can’t complain about it being another piece of junk because they do something useful, they come in all sorts of shapes and sizes and are great beginner projects and once you’ve built it, you can tell people “I made that”.

Recently, I’ve been working on a new clock project and it suddenly occurred to me that except for the physical display aspect of the clock, the internals are nearly always the same. A battery-backed RTC for the date/time (usually a Dallas DS1302) with support components, a PSU section of some type that usually puts out 5v for the logic and possible an additional higher voltage for larger LED displays, a PIC to glue everything together and some display driver hardware.

The only really custom part is the physical display, and the PIC firmware, and this got me thinking; “Can I construct a generic clock that can have many different displays connected, and just need to update the PIC firmware as required”?

So, this is what I’m currently working on. Some more thought is required on some of the projects finer attributes but I have an initial prototype sat on my breadboard that’s driving a strange looking LED display with 60 LEDs on it (I’ll post pictures later) and it seems to be working well.

The next part is to design several other display units and make sure that they can be driven by the hardware.

I use a DS18B20 temperature sensor IC in several of my projects and I encountered an interesting problem recently. This IC runs over Maxim’s 1-Wire interface and should, in theory, work over cable lengths of several hundred meters or more.

However, when I tried to run one of these sensors over a cable longer than around 50cm it refused to work. Shortening the cable always brought the sensor back to life.

In desperation I tried a different sensor and hey-presto, it worked on my test 5M cable.

So, I purchased 10 sensors off EBay and gave them a try. Each one worked perfectly on my 5M cable so I can only assume that I’d been unlucky to have a semi-faulty sensory IC.

I’ve binned this IC as whilst they are rather expensive if you buy from a regular supplier, at less than £2 each off EBay, I wasn’t going to risk having the IC suddenly fail on my at some point in the future; and there’s obviously something wrong with it.