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Bunnings site rip

Some time ago I fool­ish­ly vol­un­teered to per­form a site rip of https://www.bunnings.com.au/ for the local SES group I am a mem­ber of. This was to allow our accoun­tant mem­ber to more accu­rate­ly assign a val­ue to our assets. I under­stand this is an impor­tant thing for an accoun­tant.

I have done a num­ber of site rips in the past, the Bun­nings site is prob­a­bly the most painful so far. The prod­uct pages are very com­plex for what they are.

Each Bun­nings prod­uct page is rough­ly 300k. I extract­ed 1.1k of con­tent from each page. So 99.63% of it basi­cal­ly use­less, or an effi­cien­cy rate of 0.4%. The vast major­i­ty of the space is tak­en up by the nest­ed menu at the top, the ads near the bot­tom take a bit and then there is a fair­ly exten­sive site map across the bot­tom. At least the CSS is in an exter­nal file, well, four of them.

There is a mobile web­site which is a bit slim­mer. I think the page served is trig­gered by brows­er fin­ger­print­ing and cook­ies. I didn’t dis­cov­er it until too late though.

There are also two dif­fer­ent HTML struc­tures used for prod­uct pages, they look sim­i­lar but have dif­fer­ent tags with dif­fer­ent class­es.

And a fun trick, these two links go to the same page:
https://www.bunnings.com.au/romak-m6-high-tensile-course-hex-nut-10-pack_p1100797
https://www.bunnings.com.au/nobody-nibbles-nuts-like-noddy_p1100797

That trick gets less awe­some when you realise that they actu­al­ly do this and link to the same prod­uct with dif­fer­ent urls, 626 times.

In case any­one else is feel­ing fool­ish enough to try this them­selves, and brave enough to look at my code, the end result of my tri­als and tribu­la­tions is on github. All the mis­takes have of course been purged from the his­to­ry so it looks like I just bril­liant­ly did it in one go.

https://github.com/lod/bunnings-siterip

Microwave project managing – week 2

Manufacturing

The vis­it to AMAPRO on Fri­day was a sig­nif­i­cant suc­cess, I feel con­fi­dent enough about the process that I didn’t fol­low up my oth­er tur­ret punch­ing options.

The com­pa­ny is run by a man who strong­ly reminds me of some­one I have worked for recent­ly, and to a less­er degree an ear­li­er boss. This simul­ta­ne­ous­ly reas­sures me that he will do a good qual­i­ty job and also ter­ri­fies me because I am where he extracts his mon­ey.

The fac­to­ry floor tour was very impres­sive, an expan­sive space but very clean, no clut­ter. I was most inter­est­ed in their three Ama­da tur­ret punch machines, recent mod­els which seemed well main­tained, one was also fit­ted with an auto­mat­ed feed allow­ing it to run unsu­per­vised overnight. They also had a num­ber of press brake machines, some auto­mat­ed welders and a range of oth­er stan­dard tool­ing toys.

The com­pa­ny has two engi­neers that do design work, includ­ing devel­op­ing their own AMAPRO prod­ucts. I will prob­a­bly use them to assist in shift­ing from my sketch­es to a man­u­fac­turable prod­uct.

It was rather dif­fi­cult to dis­cuss price esti­mates, part­ly because it was very ear­ly in the design process, I also got the feel­ing that any final quote will vary great­ly based on the quan­ti­ty. They also offered that pric­ing for pre­lim­i­nary design and tool­ing work could be based on the even­tu­al final order, some­thing I am wary of because I intend to get at least one oth­er quote for the final job.

The costs looks at being above $150 but haven’t tak­en into account the front face. For the ini­tial cal­cu­la­tions I am going to assume the front will also be met­al, to avoid the plas­tic tool­ing costs, and work with a chas­sis price of $200. This is a sig­nif­i­cant per­cent­age of my tar­get cost, high­er than I was hop­ing for, but the cost struc­ture does have the advan­tage of being fair­ly lin­ear based on quan­ti­ty. I also think I will be able to offer the choice of cheap­er met­als with enam­el and pow­der coat­ing or full stain­less as the tool­ing is iden­ti­cal. There are some oth­er options which may be able to get the even­tu­al cost down but they come with con­sid­er­ably more risk.

The mechan­i­cal por­tion of the fea­si­bil­i­ty stage is now com­plete. When I get around to pro­to­typ­ing I will prob­a­bly build the first pro­to­type myself in the garage, then draw up a for­mal design and do one or two rounds of small run man­u­fac­tured pro­to­types.

Thermal Imaging

I also spent some time inves­ti­gat­ing ther­mal imag­ing sys­tems. I have decid­ed on two devices to buy and inves­ti­gate fur­ther, both are very dif­fer­ent.

The first is the Seek Ther­mal cam­era. This is a phone attach­ment which retails for $250 US, the lat­est after a series of Kick­start­ed prod­ucts and an entry from FLIR. The com­pa­ny is inter­est­ing, the founders have a sol­id his­to­ry in the indus­try, their pri­or com­pa­ny was pur­chased by FLIR and they recent­ly got a healthy check after FLIR tried to attack them through the courts. The cam­era seems amaz­ing, sig­nif­i­cant­ly bet­ter res­o­lu­tion than any­thing else on the mar­ket under $1000 and has a ther­mal range up to 350 ° C, many oth­ers cap out at around 100 ° C. The sub­stan­tial down­side is that Ther­mal makes their own sen­sor pack­age and don’t sell it as a com­po­nent, I am going to have to talk them in to chang­ing this. It is also rather expen­sive.

The oth­er is the Pana­son­ic Grid-Eye 8x8, a com­po­nent which pro­vides a 64 pix­el array of tem­per­a­ture. The main advan­tage is that it is price com­pet­i­tive, $39 USD in sin­gle unit quan­ti­ties, the eval­u­a­tion board is only $75 USD. The dis­ad­van­tages are sub­stan­tial, the res­o­lu­tion is poor and the tem­per­a­ture range caps out at 100 ° C. How­ev­er while the pic­ture won’t be near­ly as good to look at com­pared to the Seek Ther­mal I think the res­o­lu­tion will be enough for the func­tion­al­i­ty I envis­age and tar­get tem­per­a­tures tend to be under 100 ° C.

Worth men­tion­ing is the MLX90620, my third option. This was used by the IR-Blue project, one of the ear­ly Kick­start­ed infrared phone prod­ucts. The sen­sor pro­duces a 16x4 pix­el array with a tem­per­a­ture range up to 300 ° C. How­ev­er at $87 USD per unit it sits in an uncom­fort­able space between the two oth­er prod­ucts, bet­ter than the Grid-Eye but nowhere near as good as the Seek Ther­mal. I may revis­it it if the oth­er two don’t work out.

Display

I was hop­ing to find one or two options for the dis­play this week but didn’t get around to it.

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Microwave project managing – week 1

Mechanicals

So the last week has been spent dom­i­nat­ed by get­ting my head around mechan­i­cals.

I had fan­tas­tic vis­its to three met­al stamp­ing man­u­fac­tur­ers, Div­er, IXL and Com­po­nent Indus­tries. All three were help­ful well beyond expec­ta­tions, espe­cial­ly since they realised very quick­ly that I wouldn’t be able to use them.

I under­stood that met­al stamp­ing had upfront costs which were off­set by the reduced unit costs. What I didn’t under­stand was the scale that they work at. Stamp­ing is good once you want 10,000 of some­thing and real­ly sweet once you add anoth­er zero to that num­ber. My pre­lim­i­nary work­ing num­ber is 500, so I have to use dif­fer­ent tech­niques.

The low­er cost method is a com­bi­na­tion of tur­ret punch­ing, laser cut­ting and fold­ing. I have actu­al­ly played with sim­i­lar tech­niques in a met­al sculp­ture course I did a few months ago, I just didn’t think they would come into play for this kind of prod­uct. I have vis­it­ed a laser cut­ter, Beyond Laser who promised that if I could draw it, he could cut it. I also have a vis­it lined up with AMAPRO and Cono­mat­ic for Fri­day.

It looks like what I am after is pos­si­ble. I should have a much bet­ter idea on Fri­day but it seems like I am look­ing at $100-$150 for the mechan­i­cals. This will involve more labour than the stamp­ing tech­nique and it may be worth look­ing over­seas to reduce the costs.

There are also some sig­nif­i­cant unknowns with the mechan­i­cal design that impact the cost, such as what hap­pens if you put sharp cor­ners in the microwave cham­ber.

Inverters

The oth­er main task was look­ing in to using invert­er tech­nol­o­gy. This was less fun. Basi­cal­ly the tech­nique is tied up with patents, pri­mar­i­ly held by Pana­son­ic. The non-Pana­son­ic invert­er microwaves seem to be either licenced or rebadged Pana­son­ics.

Being able to buy the Pana­son­ic guts would actu­al­ly be ide­al for me and seems like fair­ly stan­dard prac­tice in the indus­try. Fig­ur­ing out who to approach is not easy though, I have sent one email off and will see if it leads to a way in.

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