Blue Peter Eprom eraser

[ceedy]

Well its in the blue Peter style and I will refine it once the basic timings and performance are sorted.

But I got a 4 watt G4T5 Pond filter UV tube off of Fleabay for £3.75..

altho' you can easily build your own driver circuit .

I got a Money checker thingy.. like this


But for £4.50.. as its got a case/switch plug/sockets all in. and the pond bulb fits right in and has the same power needs. this seems a bit easier !

Chop a bit out of the packing to get at the switch and you have an eraser.

I put the Eprom at the bottom of the box and .. presto'..



you just need to correctly time it ?.. not that hard as I'm not going to be doing it all the time.

I did start the cardboard/tape mockups .. but this is a good starter.

Just don't stare at the light as it can damage your eyes.

its a good first attempt ???

Just did a 15 min wipe , but need to get the programmer delivered before I can check if its enough time.


Chris

[RedskullDC]

Hi Chris, et al.

Looks good.

The timing is not overly critical.

I use a UV toothbrush sanitizer this end to erase standard 27C EPROMS, normally takes about 20mins or so. If they aren't blank, I just put them through again.

Something like:
http://cgi.ebay.com.au/Hot-Mini-Plas...-/320677492844

Battery powered, room for a couple of EPROMS at a time, plus has a timer built in to switch off automatically.

Cheers,
Red

[ceedy]

Yikes thats even easier ...

[pandy71]

Time is critical - to high level and/or time of UV exposition (UV-C particularly - like mercury lamps) can destroy EPROM (first signs is longer time to program cell) also during UV expose time EPROM itself act like solar cell - generate electric current - good EPROM erasers connect all IC legs together and discharge memory (easily can be implemented by using plastic foam wrapped with aluminum foil and IC firmly set in such conductible surface or even better use special ESD foam - sponge - usually it have resistance around few kilo ohms - this should be very good)

btw ask girlfriend about gel (tips) nails - they use UV lamps to harden polymer lacquer - those UV lamps are quite popular and inexpensive (and better than money detector UV lamps).

[ceedy]

I wouldn't think the UV from a standard Money detector would be remotely useful for blanking an Eprom?
its the wrong wavelength UV.

But the germicidal one I've fitted will do it ok ..
but is hazardous to living things ( bacteria & us) ..

Not good for eyes or skin , most of our bits really.!

So care is needed using them .

Not sure about nail hardners either, as you put your fingerly bits in them.

Do that under this lamp ( a UVC ) and you will have problems!!
Sunburn or Worse !!


I know that Eproms can be " Over erased" well damaged if UV'd for too long ..
so will have to be experiment & work the time up gradually..

C.

[pandy71]

EPROM can be erased even by money detector UV light but it require time - UVC is most efficient. UVC exposition can rise probability of skin cancer.

[rkauer]

UV light will dry the tears from your eyes.

If you wear contact lenses NEVER REACH OR LOOK INTO AN UV LIGHT FOR MORE THAN A FEW SECONDS. The water between the lens and your cornea will dry and when you try to remove the lenses you'll rip your corneas with they.

Other than that UV light is not that dangerous for eyes.

[cosmicfrog]

I demand double sided sticky tape or its just half a blue peter hehehehehhe

[ceedy]

Originally Posted by cosmicfrog

I demand double sided sticky tape or its just half a blue peter hehehehehhe

Just for you ... . pic of my first Eprom tray,



had to rescue it from the bin :

Chris..

[Loedown]

Originally Posted by ceedy

I know that Eproms can be " Over erased" well damaged if UV'd for too long ..
so will have to be experiment & work the time up gradually..

C.

If you have a few lying around, program them all the same and then blank them one by one and vary the blanking time by increments of one minute until you work out the ideal time / reliable erase time.

A digital timer with automatic cut off would be an ideal companion to your current setup

[ceedy]

Originally Posted by Loedown

If you have a few lying around, program them all the same and then blank them one by one and vary the blanking time by increments of one minute until you work out the ideal time / reliable erase time.

A digital timer with automatic cut off would be an ideal companion to your current setup

will have a go at this when my programmer arrives , then I can check if empty or not .

A timer is being planned ...

but I've got ( pardon the pun) .. time on my hands ..
so can easily baby sit the few erasing sessions

I've even nicked my wifes kitchen timer on a string , so can keep it round my neck if need be !! as I'm easily side tracked .....
C.

Originally Posted by rkauer

UV light will dry the tears from your eyes.

If you wear contact lenses NEVER REACH OR LOOK INTO AN UV LIGHT FOR MORE THAN A FEW SECONDS. The water between the lens and your cornea will dry and when you try to remove the lenses you'll rip your corneas with they.

Other than that UV light is not that dangerous for eyes.

"rip your corneas"

So not too dangerous then ..... .

Chris

[pandy71]

Fancy erasers read EPROM - if all cells are 255 ($FF) then erasing is finished.

[ceedy]

Q? ..

if i try to erase a Eprom for a set time and its still not blank, is any further time incremental on top of the previous period or do I start all again ?? and just increase the time period each go ??

does that make sense ??

Chris

added... from info I've found , it looks like the erasure time is incremental ?

[ceedy]

Had few goes ..

Looks like its about 40 mins to erase a Eprom with this

4 watt bulb.

Chris

[pandy71]

Older EPROM's especially programmed with old "non intelligent" algorithm are usually more difficult to erase - they require more time - for UV-A ("black light" sources for money checking) 40 minutus is acceptable - more energy faster erase - UV-B sources like those lamps for nails lacquer hardening probably erase EPROM bellow 20 minutes - UV-C sources like germicidal lamps (mercury vapor) http://en.wikipedia.org/wiki/Germicidal_lamp can erase EPROM bellow 10 minutes.
Cheap sources for UV-C are all water treatment/cleaning companies - they sell filter but also germicidal lamps and spare parts. Very cheap source for UV-C are mercury vapor lamps http://en.wikipedia.org/wiki/Mercury_vapor - there are two lamps in one usually - external bulb with white phosphor - it convert UV-C energy to visible light and block UV-C to protect environment and small internal bulb - made from quartz - this is source of the UV-C - all what need to be done is carefully brake external lamp made from ordinary glass (use old towel or lot of paper to cover whole bulb then puncture with some metal - like small hammer etc) - after removing glass internal bulb should be exposed - cut bulb from frame, connect to remains two wires switch and in SERIES (not parallel) ordinary 40W bulb - 40W bulb will act as resistor ballast to reduce current flow in UV bulb. This very cheap but very good source of UV-C - everything should cost less than 5 Euro's. Remember about how dangerous UV-C is - never watch directly working UV-C bulb, avoid exposure to UV-C, be careful with electrical network.

[ceedy]

Originally Posted by pandy71

Older EPROM's especially programmed with old "non intelligent" algorithm are usually more difficult to erase - they require more time - for UV-A ("black light" sources for money checking) 40 minutus is acceptable - more energy faster erase - UV-B sources like those lamps for nails lacquer hardening probably erase EPROM bellow 20 minutes - UV-C sources like germicidal lamps (mercury vapor) http://en.wikipedia.org/wiki/Germicidal_lamp can erase EPROM bellow 10 minutes.
Cheap sources for UV-C are all water treatment/cleaning companies - they sell filter but also germicidal lamps and spare parts. Very cheap source for UV-C are mercury vapor lamps http://en.wikipedia.org/wiki/Mercury_vapor - there are two lamps in one usually - external bulb with white phosphor - it convert UV-C energy to visible light and block UV-C to protect environment and small internal bulb - made from quartz - this is source of the UV-C - all what need to be done is carefully brake external lamp made from ordinary glass (use old towel or lot of paper to cover whole bulb then puncture with some metal - like small hammer etc) - after removing glass internal bulb should be exposed - cut bulb from frame, connect to remains two wires switch and in SERIES (not parallel) ordinary 40W bulb - 40W bulb will act as resistor ballast to reduce current flow in UV bulb. This very cheap but very good source of UV-C - everything should cost less than 5 Euro's. Remember about how dangerous UV-C is - never watch directly working UV-C bulb, avoid exposure to UV-C, be careful with electrical network.

The 30-40 mins is what it has taken to erase with a 4 watt UV-C fiited in the checker

Chris

[Amigafanboi]

A lot of hassle considering you can pick up a new eraser from Evilbay for £12.
I bought one and it erases in around 20 mins but it did take 3 weeks to arrive from China!

Edit: it's gone up to £15, here's the link if wanted.

http://cgi.ebay.co.uk/Eprom-Eraser-U...item1c15cb310e

[ceedy]

Originally Posted by Amigafanboi

A lot of hassle considering you can pick up a new eraser from Evilbay for £12.
I bought one and it erases in around 20 mins but it did take 3 weeks to arrive from China!

Edit: it's gone up to £15, here's the link if wanted.

http://cgi.ebay.co.uk/Eprom-Eraser-U...item1c15cb310e

my reason for doing this...

1.. Couldn't wait !!

2. easy to do.

3. needed something to do waiting for the programmer
actually only took 2 mins to change the bulb .

4. cost under 9 quids

5.. ermmmm! pass!

C. ...

[Amigafanboi]

It was more aimed at Pandys instructable, i broke into a sweat just reading it

[ceedy]

Originally Posted by Amigafanboi

It was more aimed at Pandys instructable, i broke into a sweat just reading it

me too!!! ... ....