Extra bits Picaxe store might consider stocking

locky42

New Member
Maplin have now gone bust !!! ekk where did I put that RS catalogue ?

But there are items I'd like the Picaxe gurus to consider stocking.

The first is a red, yellow and green 5volt LEDs laid out like traffic lights. These are available from model shops. But there was a time when
writing software to sequence and control traffic lights was an early stage in learning to program control sequences. Get the sequence for one set right, then
incorporate traffic lights for intersections. I would say it should still be there for 9 to 11 year old future engineers.

The second is Read Relay contacts. They can be present in door open/closed switches as well as sensing when the thing with the magnet comes close.

Finally, something to bridge out the Octal Darlington driver chips.e,g the ULN2003A and/or the ULN2803A This is for when needing to use boards like the 14M and 18 Project Boards
for simple TTL output. I have used 2 options that work. That is replacing the Darlington chip with an octal dip switch, being careful not to short out the battery. An alternative is an Octal bar graph LED chip.
In the end I got a small narrow strip of Vero and soldered pins where the legs of the original chips went. But in all 3 cases I could 'revert' very quickly.
 

stan74

Senior Member
If everything in maplin was 50% off it would still be more than cpc/farnell or ebay...that's why the went bust..more staff than customers.
The shop in my town was handy when rs and cpc were trade only.
 

erco

Senior Member
The second is Read Relay contacts. They can be present in door open/closed switches as well as sensing when the thing with the magnet comes close.
Think you mean a reed switch. Our local Dollar store has complete window alarms for a dollar (!). Contains a reed switch, magnet, loud DC beeper, and 3x button cells. Those have saved me on several projects after hours when my local electronic store is closed.
 

stan74

Senior Member
Exactly erco!
It's hard to think of something to make that is already made for less cost than one could make.
Weather stations come to mind,remote one £10 lidl...(a German super market chain like aldi)
I google weather mytown...or look out the window.
I remember a radio shack-tandy store in my town long before a maplin store.
I got a 5 inch screen crt tv for my mum from there.
Everything was packaged.. even a resistor!
It was sinclair zx81 days and they did 2114 ram for £5...you needed 2 to work.
Long gone.
 

erco

Senior Member
Another item worth considering for the store might be LEDs with integral resistors. There are arguments against, but since blinking an LED is likely the first hardware experience for noobs, it makes sense to avoid potential problems. There is still a polarity issue, but why not simplify as much as possible?
 

erco

Senior Member
Of course they look just like a regular LED, so once they get mixed together, it's game over for noobs. Perhaps an LED with an obvious presoldered resistor would be better.

 

premelec

Senior Member
For 75 years I've been stripping discard electronic devices for useful parts... just some time and solder... thousands of parts ;-0
 

stevesmythe

Senior Member
Rev-Ed do actually stock two types of reed switch. The "barebones" type - search for SEN056 - and a mounted version "proximity switch" - SEN055.
 

AllyCat

Senior Member
Hi,

RS in the UK is Radio Spares.
Well they were until 46 years ago when they changed their name to RS Components. :)

For a time they would supply only to "Industry" (and Educational establishments) but not to "hobbyists". Now they do, but their Minimum Order Quantity sometimes can be a hurdle. I may be happy to buy 10 LEDs if I need only one, but not 10,000. :(

A problem with reed switches is that they are not all created equal: A few years ago, I needed a replacement insert for my anemometer (wind speed sensor) and was delighted to find one that looked identical, inside a "window alarm" similar to that described by erco (two for £1 in Poundland). So I replaced my broken reed, but fortunately then put the anemometer "on test". Within 24 hours it had failed (loss of "spring" in the contacts) and so did a second. A few thousand operations may be satisfactory to detect the opening of a door/window, but an anemometer really does need that 10+ million/billion operations. ;)

Cheers, Alan.
 

erco

Senior Member
When I used the reed switched extracted from the window alarms, it took a few tries to get them oriented right. They are quite sensitive to the location of the magnet, axially and radially. Since they are tiny and symmetrical, it just comes down to continuous testing during installation.

Per Alan, many in use have demonstrated very long life (anemometers and bicycle wheel sensors) but like everything else, quality varies. It might not be prudent to use Dollar/pound store parts in mission critical hardware.
 

Brian M

Member
Never used Maplin in years, I always use CPC Farnell. Extensive catalogue and prices that beat Maplins by far. They are a subsidiary of their parent company Farnell whose direct equivalent is RS Components. The CPC catalogue can be viewed online, quality is reasonable, I've never had a problem with CPC, and if you live in the North West of England their trade counter in Preston is open most days including Sundays and most Bank Holidays.
As for Maplins, sorry, but I don't think I'll miss them.

Link to CPC catalogue

http://www.easyflip.co.uk/CPC_Digital_Catalogue/?page=1
 
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