[tech] Vending Machine 3 Button & MIFARE Reader

[Mark Tearle]

Hi Mitch

I've applied and push the patch to the git repository.  I'll leave you
to update the running copy.

Mark

-- 
Mark Tearle <mtearle at ucc.asn.au>

On Wed, Mar 4, 2015, at 02:53 PM, mjpomery at ucc.asn.au wrote:
> Hi Mark,
> 
> As per my email last night, attached is a patch to fix the bug 
> introduced with the fix to MIFARE card reading in the Vending Machine. 
> The card reader won't read a card that isn't linked to an account when 
> you log into the machine to enrol it, if it was the last card tried.
> 
> Hi Door,
> 
> The Important Bit (For Door members who skim this):
> It also seems that there is an issue with reading some student cards. 
> They are not picked up by the card reader at all (so it isn't even 
> getting to my code changes). I haven't seen it personally, so if anyone 
> sees this happening, can they make a note of who it was if I'm not 
> around the clubroom, or grab me if I am there.
> 
> Regards,
> Mitch Pomery
> UCC President 2014
> 
> 
> On 2015-03-04 00:00, Mitchell Pomery wrote:
> > The Three Button:
> > 
> > As we all know, the vending machine's 3 button is the worst thing that 
> > can
> > ever happen to you. But worry no more, for I had an ingenious idea that
> > worked!
> > 
> > What was the problem:
> > The three button the the vending machine bounced, meaning it was not
> > uncommon to get four 3's when you only wanted one. This was the state 
> > it
> > got two when I finally got fed up with it.
> > 
> > How I tried to fix it:
> > I tried to impliment hardware debouncing, but found it largely
> > unsuccessful due to the type of button and the inability to rewire it
> > nicely.
> > 
> > What I ended up doing:
> > Desoldering both the 3 and the reset keys, swapping the switches then
> > soldering them back in.
> > 
> > What the end result was:
> > I was expecting the reset key to bounce, but it did not. The three 
> > button
> > did not bounce either. I somehow managed to take a bouncy switch and a 
> > non
> > bouncy switch and create two non bouncy switches.
> > 
> > MIFARE Reader:
> > 
> > The new MIFARE reader is capable of reading cards much faster than the
> > previous one was. This meant that people enrolling new cards would see
> > "Card Already Enrolled" when they first held it up. This did confuse 
> > some
> > of the new members. Since then I have patched VendServer to only read 
> > each
> > card once. When you hold a card up to the reader, it will be read 
> > multiple
> > times, but the software will only act upon that card once. Using 
> > another
> > card or logging out of the machine is enough to get it read again.
> > 
> > And while typing this, I have thought of a potential bug: Holding a 
> > card
> > up that is not linked to an account. I will investigate this sometime
> > tomorrow.
> > 
> > The Eternally Busy,
> > Mitchell Pomery [BG3]
> > _______________________________________________
> > List Archives: http://lists.ucc.gu.uwa.edu.au/pipermail/tech
> > 
> > Unsubscribe here:
> > http://lists.ucc.gu.uwa.edu.au/mailman/options/tech/bobgeorge33%40ucc.asn.au
> Email had 1 attachment:
> + MIFARE_bug.patch
>   2k (text/x-diff)