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1  Community / Bar Sport / Re: Reality check - when to stop adding features on: Today at 04:56:12 pm
Finally, I thought... well, at least I get quoting for free.  I can programmatically add the `tick marks`, and even recognize table.column pairs and quote them separately (i.e., "table.column" becomes "`table`.`column`").  But, that's a weak argument in the cost-benefit analysis, and how do you even know what's a column name and what's a literal?  Or a function?  You pretty much have to write a basic SQL parser that is context-aware ... and even then, you can't reliably tell a text literal from a column name without knowledge of the schema.

One of the reasons you use the tick marks with MySQL queries is to protect yourself when you encounter reserved words. Assuming you've debugged your code and/or created a parser "today" to make sure you're protected, you still have no way of predicting what reserved words or new syntax will appear in future versions of MySQL. The only valid tick-mark-parser would need to be a facility included in the MySQL driver itself.

2  Development / Suggestions for the Arduino Project / Re: Arduino CNC PCB Plotter (Need Ideas) on: Today at 04:29:23 pm
There are a number of 3D printer controller boards that will work from G-Code stored on a SD card. The most known would be the RAMPS boards (google "SDRAMPS"). Appears that most sellers of the RAMPS boards on eBay don't include the little SD card add on module, but you'll find it if you look for it.

http://www.ebay.co.uk/itm/RAMPS-1-4-electronics-SD-RAMPS-and-cables-RepRap-3D-printer-/170913041178
3  Using Arduino / Motors, Mechanics, and Power / Re: Looking for High Torque Servos. on: Today at 12:58:25 am
You need something like a "crane" and not an "arm". One servo to raise/lower the boom and a second servo to pan the boom between tanks (where the tanks are arranged in a semicircle). Personally I'd just hang the board off a wire hook instead of trying to use a gripper, and if you want agitation you could put a continuous rotation servo on the end of the arm so that it raises/lowers the board as it spins.

You don't need much torque for the pan, and because you can counterbalance the boom you don't need much torque there either. Any standard size servo would handle it, but always a good idea to shop around and try to find ball bearing / metal gear servos. Hobbyking.com has plenty of generic servos that would meet those specs for not much dough (<$10).
4  Using Arduino / Sensors / Re: dirty earth - automotive / car application on: Today at 12:47:18 am
It'd be worthwhile knowing what kind of car this is (modern car or older/classic) as well. Older cars don't have the protected electrical system that modern cars have.
5  Using Arduino / Motors, Mechanics, and Power / Re: Driver options for the Nema17 on: Today at 12:43:33 am
What I need from my motors is sufficient torque that they do not loose speed when brushing lightly over a rough surface with a soft painting brush.

http://watercolorbot.com/

You can see they're using NEMA 17 size motors and judging by the axial length they're probably about the same torque as what you have linked on the Farnell site.
6  General Category / General Discussion / Re: Counterfeit or real? on: August 31, 2014, 12:03:32 am
4tronix is listed as an official Arduino distributor.

If the seller isn't on the list then it's counterfeit. The Arduino guys are pretty diligent with keeping that list accurate.
7  Using Arduino / Motors, Mechanics, and Power / Re: Solar heating with motorized satellite dish on: August 29, 2014, 10:07:10 pm
This is one example how to build it relatively cheap:
https://www.youtube.com/watch?v=-SsJBobMpAk

They show the collector being used to heat water which is then pumped through a radiator inside the building to keep chickens warm. But you know what would be an even cheaper way to use solar power to heat the building? Windows and/or transparent roof panels.
8  Using Arduino / Project Guidance / Re: Sending IR Commands via Analog on: August 29, 2014, 09:40:36 pm
If you're using the IR library you'd need to do some hacking of that library to get it to work how you want. The IR library is written to send pulses to an IR led which an IR receiver then translates into pulses of a different pattern depending on the IR code in use (Sony, Panasonic, RC5, etc.).

I know it seems silly but it'd be a lot easier to just stick an IR led on your board instead of wiring everything directly.
9  Using Arduino / Project Guidance / Re: Can a single gps reciever get a RTK accuracy? on: August 29, 2014, 09:31:43 pm
But the question remains. An independent GPS unit capable of cm accuracy and costing less than (for example)  $500 would command an enormous market, so why isn't it here already?

I don't think the market is that enormous. For people around here, sure, I'm sure you could sell quite a few. But for the guy that wants it for something like car navigation no; like RH314 said you need that data stream from a second, fixed receiver so that would require (most practically) a cellular connection, and that service would get expensive for everyday use. And you don't need cm-level accuracy to find the nearest gas station.

But there is a market, and I think if you built a turnkey system using Navsparks for under $500 you'd get a lot of buyers. For all those companies in construction, farming, etc. using the expensive RTK systems that we've seen thus far you won't be likely to grab that market -- those existing, high prices imply guarantees from the respective manufacturers (Caterpillar, Deere, etc.) that it'll work right and that the integration is seamless. It's similar to how a company like HP can sell a 1 TB disk drive for $300 for a Proliant server; the buyer is expecting guarantees and is thus willing to pay 3x the street price for the product. That's not to say the buyer is making a wise choice, mind you, but that's how the market works.
10  Using Arduino / Project Guidance / Re: Autogravure Project on: August 29, 2014, 09:04:59 pm
Sounds like you should look at GRBL (or a similar firmware). It would require that you communicate with your machine using GCODE, but GRBL does support commands for bidirectional communication. It would at least provide a basis for you to start from and you could extend it to meet your needs. You're looking for control of five motors so you might need to look at those alternate firmwares -- or I suppose you could always add a second controller.

Under normal circumstances I don't think Windows supports real time control with a USB port -- you can't send step/dir/etc. command pulses in a timely manner like you can with a parallel port. With GRBL all of the real time activity is handled by the microprocessor itself.

11  Using Arduino / Project Guidance / Re: light barrier for airplanes on: August 28, 2014, 08:59:13 am
I'd suggest using an upward-facing USB camera and Roborealm ($50) to identify the passing of the plane. Any other option would require you to attach a beacon (lamp, battery, and circuit) to the plane which would not be acceptable to your plane-flying friends.
12  Using Arduino / Motors, Mechanics, and Power / Re: setup with two stepper motors 28BYJ48 12 V on: August 28, 2014, 08:30:57 am
Those 28BYJ-blah steppers are geared steppers with a ratio near 64:1 (it's actually a non-integer steps per RPM). Because of that you'll only get them moving around 10 RPM. If you're using a belt and pulley (not a leadscrew/threaded rod) system -- like a printer uses -- you might be able to get decent speed. But beware that the cheap steppers you're using aren't incredibly precise and can lose steps.

For best speed with a stepper you want more voltage driving them. The Adafruit motor board, with its L293 chips, is a fairly antiquated architecture and won't give you good performance. You should be looking for ungeared steppers, probably NEMA 17, and a "RAMPS" board with A4988 drivers. These days you can get a full package pretty cheaply.
13  Using Arduino / LEDs and Multiplexing / Re: Led Driver from Adafruit where to buy in Germany? on: August 28, 2014, 08:10:59 am
Also look up tutorials on using the TLC5940. It's only 16 channels (5 RGB leds) but you can get it in a DIP format which is of course easy to work with. You will find lots of sellers of that chip.
14  Using Arduino / Microcontrollers / Re: Standalone Atmega328 locking up on: August 28, 2014, 08:06:39 am
There's a separate cap between AVCC and GND and VCC and GND to help keep the noise from the digital side of the chip and circuit from interfering with the analog readings that are being handled on the analog side of the chip. It's not a necessity but it's important where you require premium accuracy from your analog readings. It's rare to see it but sometimes you'll also see designers building boards where the analog GND and digital GND are kept completely separate and only connect right near the power source.

15  Using Arduino / Project Guidance / Re: Add own atmel controllers on: August 28, 2014, 06:58:25 am

Newark/Farnell have had some really low pricing on the 328's lately.

http://octopart.com/partsearch#!?q=atmega328P
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