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826  Community / Bar Sport / Re: A project to prevent a homocide on: October 04, 2012, 05:41:59 pm
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Don't laugh, once I managed to step on a hot soldering iron while in sock feet.

On a serious note, I stepped on a burning charcoal from the barbeque 25 year ago, and just dunked my foot briefly in the swimming pool.
A friend told me to leave my foot in the pool for several minutes ( to stop it cooking ) but I knew better, and didnt even cover the blister when it burst.

I now have one foot 1 size bigger than the other while rested, and much bigger than that after standing or walking all day.
Luckily the climate here allows me to be barefoot, or to wear adjustable strap sandals all year, otherwise I would have a massive shoe budget !

OK, the producers of " Finding Bigfoot" can rest now, he is in Cape Town :-)

Oh dear, I have just noticed this is post 666 and I am a God member ?  :-(
827  Community / Bar Sport / Re: Why don't CPUs and microcontrollers operate on 24v? on: October 04, 2012, 05:30:38 pm
There is another consideration for using higher voltage, ( as in CMOS at 12v that I designed around for 40 years until I saw the Arduino light )

With  12v CMOS logic there is a typical 0.45vcc noise immunity ,  so 4 volts of noise on an input can be tolerated without it corrupting an input.

I havn't yet built an embedded Arduino project for a car ( although I do have one in the pipeline ) but I would be wary about using 3v3 logic without a buffer and filter for that notoriously ( electrical ) environment.
828  Community / Bar Sport / Re: Why don't CPUs and microcontrollers operate on 24v? on: October 04, 2012, 11:17:12 am
In 2 years I migrated from 12v cmos techology, to briefly 5v logic, and now it seems 3v3 for the GPS / transceiver type modules available.

I think that the 24v , or 5 volts can flash over between tracks in the chip, with the spacings they need to use , so 3v3 works with the micron spacing for these chips.
829  Community / Bar Sport / Re: A project to prevent a homocide on: October 04, 2012, 08:56:20 am
Chuck Norris and I often solder wearing shorts  -   Chuck doesn't scream though when the blob of solder descends  :-(
830  Community / Bar Sport / Re: Can 3D Printers be used to print PCBs? on: October 04, 2012, 04:40:54 am
Oh for a 3D printer, and the time to experiment with it !

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I'd have the parts clipped into a 3D printed plastic frame

That might be the way to go, have each component sunken into the plastic layer, with just its legs standing proud, bare parallel wires connecting them, and an insulating layer before the next lot of wires crossing the first ? ........
831  Community / Bar Sport / Re: Can 3D Printers be used to print PCBs? on: October 04, 2012, 04:23:57 am
Thats interesting,  perhaps after the first layer, you put a punched ? silicon sheet on top, and build up the vias through the holes, with the layer 2 tracks on the top?
832  Community / Bar Sport / Re: Can 3D Printers be used to print PCBs? on: October 04, 2012, 12:25:07 am
Just thinking about this pcb making.

What if an old Lexmark ( or whatever ) inkjet could be modified to pull a plain piece of heatproof board through ( instead of paper ) and the print head replaced with a nozzle pushing out tiny drops of copper in a solution or paste.
It would probably have to be very slow, but then the board could be flash heated to remove any solution, and fuse the copper particle together ?

Just excercising the brain before a busy day :-)
833  Community / Bar Sport / Re: Can 3D Printers be used to print PCBs? on: October 04, 2012, 12:14:32 am
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loved the old "cordwood" PCB fab method shown on that wikipedia page...

The original Boeing 747 passenger service/entertainment mux system components had several cordwood modules in them.

I used to marvel at how the hell they got all the components leads through the holes on the second side pcb !

I had to do a similar task recently, feeding 75 diodes leads through holes in a pcb ( because I havn't found an edge connector yet to fit the BCD switches I use )  but at least the board was quite big compared to the little cordwood modules .....
834  Community / Bar Sport / Re: Join the resistance! (humor) on: October 02, 2012, 01:25:01 pm
Very good,  but  do I sense some underlying reluctance amongst the monks ?
835  Using Arduino / Project Guidance / Re: squeezing out the last of the pins .. on: October 02, 2012, 03:24:38 am
OK, 

Code:
NewSoftSerial mySerial(0, 15);

works fine, problem solved , I am not actually connecting anything to the RXD pin, and coms are fine with the IDE for programming.
836  Community / Bar Sport / Re: Freebie from Mouser on: October 01, 2012, 10:42:13 pm
I tried ordering the book ( I am in South Africa )

If its only 63 pages and they are giving it away, why don't they just let us download it as a pdf ?
837  Using Arduino / Project Guidance / Re: squeezing out the last of the pins .. on: October 01, 2012, 10:31:19 pm
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Is there any way you can add a few extra IC's. You can read 8 BCD switches with just 6 or 7 pins.
The other pcb I have spare uses just 6 pins to read 16 switches ( or any multiples of 8 switches )  but I dont want to waste it on a project with just 8 switches, as it looks like I will need that pcb for  another project next week.

I will only be transmitting from the remote, so I will not even connect anything to the transceivers TX pin,  I was just wondering what rules there are about mixing hardware and software serial pins when declaring the pins.

I suppose I can have a look at the easytransfer library, and see if it will work with Serail.print instead of using NSS ?  Its basically just 11 bytes I want to transmit.

I have tested the transceiver just using Serial.print and it works, but I really like the checks that easytransfer uses.
838  Using Arduino / Project Guidance / squeezing out the last of the pins .. on: October 01, 2012, 04:13:37 pm
I am making a remote control with 8 bcd switches, and 4 pushbuttons.  ( using a 328 chip programmed on an Arduino board, but plugged into an embedded board )
I do have a spare pcb that can handle 18 bcd switches and has lots of spare pins, but it is not practical for the enclosure I am using. ( it has 4017 chips to expand the inputs )

I have made some small bareboard pcbs that I can use, but I have used 17 pins already for the switches.

I want to use the Easytransfer library, which runs on the NewSoftSerial, which I think needs both a Tx and Rx pin declared?

Can I define the TX pin as 4,  and the hardwire serial RXD pin ( pin 2 ) as the RX pin for the NSS ?  I wont be using the RX pin.
839  Community / Bar Sport / Re: The ARMs race on: October 01, 2012, 04:23:25 am
Good point  Mark.

As long as I dont have to go back to micro nursery school again !
840  Community / Bar Sport / Intelligent transceiver SIM20 on: September 30, 2012, 03:06:49 am
I have been experimenting with the SIM20 this week, very impressed with it once I had worked out the datasheet,

some parts of which seem to say the module is more intelligent than the user.  i.e.

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3.3 Turn-on and turn-off of the SIM20

3.3.1 Turn on SIM20

SIM20 can be turned on automatically when power is supplied.

3.3.2 Turn off SIM20

Users can turn off SIM20 module by cutting off power supply.

:-)
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