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Flamin Heck - Chunkulator - NSW
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Nick
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Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW


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I can't find a Jetboil stove with a separate tank, they seem to be discontinued. If I can locate some old stock, I am shamelessly stealing your idea Laughing.
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Post Mon Jan 23, 2017 5:49 pm 
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chunkulator



Joined: 27 Jul 2016
Posts: 219


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Go for it. They're still listed on the Annaconda website and there was plenty of stock at the Belrose store when I went in a couple of months back:

https://www.anacondastores.com/camping-hiking/camp-cooking/camping-fuel-fire/jetboil-isobutane-propane-fuel-mix/p/BP90005284

Also, if the jetboil ones go out of stock, there seem to be other manufacturers who make 100g gas cans.

Post Mon Jan 23, 2017 6:46 pm 
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Nick
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Joined: 16 Jun 2004
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Location: Sydney, NSW


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Its the tank adapter that I can't find. there is a picture of it in the banner Jetboil's web site but none of their cooking systems show a disposable tank. If I can find some old stock, it will be easy to update the old flame-thrower I already have.
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Post Mon Jan 23, 2017 7:15 pm 
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chunkulator



Joined: 27 Jul 2016
Posts: 219


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Ah, that's easy. It's the standard fitting found on larger camping canisters and screw-type butane canisters. Something like this will do it:

http://www.ebay.com.au/itm/Universal-Gas-Stove-Adapter-Hose-Connector-Regulator-for-Outdoor-Camping-/332012153447?hash=item4d4d776a67

Post Mon Jan 23, 2017 7:35 pm 
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chunkulator



Joined: 27 Jul 2016
Posts: 219


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Cutting through those stainless steel braided hoses and putting them on a hose barb with a hose clamp is no picnic though. Very difficult to get a neat result and wear gloves! I have considered going to these people to see if they'll professionally crimp the end for me:

http://gameco.com.au

Post Mon Jan 23, 2017 7:40 pm 
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Nick
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Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW


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Ha ha, China to the rescue as usual!
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Post Mon Jan 23, 2017 7:49 pm 
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Nick
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Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW


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Maybe a slightly more expensive option would be easier to adapt: http://www.ebay.com.au/itm/Metal-Camping-BBQ-Stove-Split-Type-Gas-Tank-Conversion-Head-Hose-Adapter/252716306430?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D2220071%26algo%3DSIC.MBE%26ao%3D2%26asc%3D39923%26meid%3D629759a2caae432ca4dea144e9c140ac%26pid%3D100005%26rk%3D6%26rkt%3D6%26sd%3D332012153447

The end of the hose will have a threaded fitting that *should* match some standard.
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Post Mon Jan 23, 2017 7:51 pm 
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chunkulator



Joined: 27 Jul 2016
Posts: 219


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I suspect you will find that that's exactly the same hose. The extra bit you're paying for is the stove (which may be worthwhile if you can pull the inlet off it).

I did a quite a bit of research on the various standards at the time. It seems to be that the gas canister itself is well standardised under European Norm EN417 (https://en.wikipedia.org/wiki/EN_417) but each manufacturer does whatever they want on the other end. So you need to buy a spare hose from your stove manufacturer. The hose I bought (which looks identical the one attached to that stove you found) had a brass bit with a couple of O rings and a male thread that didn't seem to be a BS or NPT thread and wasn't metric. You might be able to work out what thread it was, buy an appropriate tap and machine an adapter. I didn't want to go there - especially without a lathe. So I cut it off and jammed it in a hose barb. It's workable but not beautiful.

BTW, I found this site very helpful in navigating the world of camping gas standards:
https://adventuresinstoving.blogspot.com.au/2011/02/word-on-types-of-canisters-and-brands.html

[/i]

Post Mon Jan 23, 2017 9:06 pm 
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chunkulator



Joined: 27 Jul 2016
Posts: 219


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I found the brass widget that goes into the stove that I cut off the end. It looks like this:






The thread could be 1/16 BSP/NPT but I don't have anything with a long enough female thread to try it on.


Last edited by chunkulator on Sun Jan 29, 2017 7:50 am; edited 1 time in total

Post Sat Jan 28, 2017 8:33 pm 
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Nick
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Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW


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You were not wrong about the weird gas fitting!
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Post Sun Jan 29, 2017 6:12 am 
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chunkulator



Joined: 27 Jul 2016
Posts: 219


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More build progress

3D printed TZ85A ESC mount:


ESCs and polycarb "mezzanine" installed:


Lit up for a test drive:


It's late so I didn't want to fang it around outside too much, but it seems to drive pretty nicely now.

Post Tue Jan 31, 2017 9:43 pm 
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Nick
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Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW


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Excellent progress, keen to see a video of that drivetrain in action!
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Post Tue Jan 31, 2017 10:05 pm 
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shakesc



Joined: 14 May 2012
Posts: 62
Location: UK


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Looking forward to seeing this go together
Like the unique ideas

Post Wed Feb 01, 2017 9:50 am 
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chunkulator



Joined: 27 Jul 2016
Posts: 219


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First driving test

https://youtu.be/c7DC-FpQ5dw

It handles pretty well I think. Plenty of traction and pushing power, good speed. Cornering at speed is a noisy affair as wheels need to slip to do this in a 6WD configuration.

Post Wed Feb 01, 2017 6:31 pm 
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chunkulator



Joined: 27 Jul 2016
Posts: 219


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Starting on the electrics

I've started sorting out the electrics for this bot. One of the remaining issues I had was to try to get the switch that supplies power to the gas working properly. When I took it to Gladstone I replaced the switch with an ESC at the last minute because it wouldn't failsafe. The ESC worked ok, but was kind of overkill for controlling a solenoid and you could never be sure at exactly what stick position the solenoid would fire. I'd prefer a proper switch.

So I dug out the switch I bought for it and checked out the failsafe:

Still busted unfortunately. The jumpers which control the failsafe don't appear to do what it says in the instructions. Others on the internet seem to also have had trouble with this unit. Some people have successfully had it work. My guess some of them come with buggy firmware, some don't.

So I thought I'd have a look if I could reprogram it. I'm used to programming Atmel AVRs and have the tools so I opened it up hoping to find one of those.


However, they've helpfully sanded the markings off the micro that's in there. Bummer. I worked out which pins were which and looked through datasheets for potential matching micros. It looked like it could potentially be an ATtiny102 or 104, so I wired it for programming to see if I could read the device ID:


No luck with this procedure. It looks like some other kind of micro. Could be a PIC12C508 for example - the location of the power and ground pins match. I wasn't going to equip myself for every different flavour of micros just to make a $10 switch work though. I decided instead to build my own.

I've made lots of PCBs over the years. Some I've had professionally manufactured. Others I've made myself using photo-resist and so forth. I've also made heaps of circuits on perfboard. But one thing I've never yet done is hand-drawn a PCB. So I thought I'd give it a crack at simply drawing the circuit on with a Sharpie. I had read that you can just use an ordinary Sharpie instead of the special $40 pens you can buy at Jaycar:


Then I etched it in a bubble-tank filled with ammonium persulfate. It came up pretty nicely:


Then I soldered it all together. It's not the most beautiful thing in the world, but it'll do:


It has an Atmel ATtiny13 AVR on it and can independently drive two BUZ71 MOSFETs. I put some LEDs on it so I can see which MOSFETs are turned on without having the full rig connected. One of the MOSFETs will drive the solenoid. The other MOSFET will control the ignition source. I'm going to try Glen's suggestion (see the "Flamethrowers - reliable ignition" thread) of pulsing the gas for a bit and then shutting it off to get the right gas/air mix for ignition, and then turn the gas back on.

Tomorrow I'll write some firmware for it and see how it goes.

Post Sun Feb 05, 2017 8:50 pm 
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