Well I am pretty sure it was the radios not 100% though but we seemed to be getting drop outs when 10+ radios were very close together. Some people found that when they moved away it started working again. _________________ Steven Martin
Twisted Constructions
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Sun May 30, 2010 8:52 pm
seanet1310
Joined: 08 Nov 2006
Posts: 1265
Location: Adelaide
wonder if its a problem for spekrums and others like that? considering they appear to be the standard with a lot of flying ranges i doubt it.
ive seen the HK take out nearby wifi where spekrums dont _________________ Remember to trust me, I am an Engineer.
That could be another thing to consider as the place was wired with WIFI. Could also be lots of other 2.4Ghz devices around reducing the bandwidth available. _________________ Steven Martin
Twisted Constructions
http://www.botbitz.com
Sun May 30, 2010 9:00 pm
Andrew W
Joined: 01 Jun 2005
Posts: 220
Location: Melbourne, Victoria
It would be interesting to see how much power the HK radio's put out. I had a spektrum tested on a spectrum analyzer a few years ago and its put out around 800mW of power.
It would be interesting to test both the spektrum and HK radios on a spectrum analyzer and see the differences.
I know the spektrum breaks the 2.4GHz band into 80 channels. The band runs from 2.4000–2.4835GHz, so each of the 80 channels represents approximately 1MHz. So each channel is very narrow and would require some quite expensive electronics to stop any drifting (a 1MHz channel compared to 2400MHz is tiny).
Sun May 30, 2010 9:25 pm
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
Was a great day!
A big hats off to Stevo for pulling together a massive effort to get this off the ground!
I took a bunch of photos with my iPhone, so here they are...
Little Ego ran around pretty good, played against Daniel's spinner for a while before one side stopped working, then the spinner just chewed on the wedge for a while before the other drive stopped and then it was gracefully disembowed Last pic shows a little bit of the damage.
100% pumped to get uMBX running before the next event and to get a rebuilt Little Ego running on pololu drives _________________ https://www.halfdonethings.com/
Sun May 30, 2010 9:41 pm
Valen Experienced Roboteer
Joined: 07 Jul 2004
Posts: 4436
Location: Sydney
spectrums (and most other) 2.4Ghz equipment uses spread spectrum to send its data, IE each radio uses the full range of frequencies and hops in between them all the time so its not 1mhz slots. They are sposed to have enough error correcting gumf in them that if they get stepped on during one hop the data will get fixed up in the next few.
The binding procedure gets the tx and the rx to agree on a code, that they use to pich the order of the frequencies.
Was it separating the transmitters or both Tx and Rx that fixed it?
Putting transmitters next to each other can cause them to "fight" with the output of one working its way into an adjoining TX and messing with things.
I figured the way they do the 2.4Ghz stuff would be more immune to that kind of near field effect. _________________ Mechanical engineers build weapons, civil engineers build targets
Sun May 30, 2010 10:08 pm
Daniel Experienced Roboteer
Joined: 30 Aug 2005
Posts: 2729
Location: Gold Coast
Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane
Marto put on a very professional day. Everything was well organised. People were asking for help left right and centre, but Marto handled all requests and looked after everybody. 100% of kits were built and got to drive on the day. I did not hear a single negative comment. You could not hope for a better build day. Well done, Steve. _________________ So even the rain that falls isn't actually going to fill our dams and our river systems
Mon May 31, 2010 4:53 am
Philip Experienced Roboteer
Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane
What would happen if you used the charger included with the kit on a smaller, say 160 mAh, battery? Would it still charge at a fixed current and kill the cells? _________________ So even the rain that falls isn't actually going to fill our dams and our river systems
Yes you would prolly end up with a small pile of fire. The solid blue ones charge @ around 800mah the clear blue ones @ around 500mah. Even @ 500mah thats like 3C. What is the charge rate on the battery?
It looks right. I would still try it externally charging a few cycles first and you will need to may a plug adaptor. _________________ Steven Martin
Twisted Constructions
http://www.botbitz.com
Fri Jun 11, 2010 9:13 pm
Fish_in_a_Barrel
Joined: 30 Sep 2006
Posts: 673
Location: Perth, Western Australia
At such a high rate you would find that the battery would lose total capacity very fast. This could be offset somewhat by adding in a diode or similar to drop the charge voltage, but the charge capacity would be reduced... etc... _________________ They say that he crossed the fine line, from insanity to genius.
Sat Jun 12, 2010 1:09 am
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
I just noticed that Ponoko is doing 3D printing as well as laser cutting. Its nothing new but they are very user friendly. The user store allows you to publish antweight parts that builders can order from anywhere in the world and if combined with laser cut steel parts, you could build an interlocking plastic frame with steel armour or bearing points - lots of posibilities there!
Thu Dec 02, 2010 12:37 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
If I ever get around to making an antweight, I'm not keen on hacked servos - what's the buzz on Fingertech's spark motors and Tiny ESC for this size bot?
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