Show Posts
Pages: [1] 2
1  Using Arduino / Networking, Protocols, and Devices / Re: Manchester Library (MCHR3k) RF Modules & Delays (Fixed, was Noise) on: December 03, 2013, 12:29:36 pm
#define TX_PIN 1

I don't think you want to be using the UART TX pin for this. The MCHR3k code uses its own timing, and the signalling isn't compatible with standard serial. Does the code work if you use the suggested pin 5?

You don't need to do additional encoding. This library sends the preamble to set the receiver's AGC correctly, masks the data to avoid zero bytes at the end of the transmission confusing the library, Manchester encodes the bit stream, and sends the correct stop bits.
2  Using Arduino / Project Guidance / Re: A Must Have: Arduino Cookbook on: March 10, 2011, 05:04:11 pm
Thanks! That discount code was really worthwhile.
3  Development / Suggestions for the Arduino Project / Re: "unix" keybindings to IDE? on: February 27, 2011, 06:05:34 pm
This would be good. I know that one of the standard Java editor tools supports them, so it's got to be in there, somewhere ...
4  Using Arduino / Project Guidance / Re: Arduino Pro and Anemometer (Reading Pulse Times) on: February 25, 2011, 09:10:32 pm
I think you might want to look at some of the tachometer examples on this board, like Counting PulseIn.

I know a bit about anemometry and wind resource assessment. Are you sure your wind vane uses a reed switch? Don't think I've ever seen one of those, unless it uses several switches to indicate wind sectors.

Typical wind vanes are either:
  • linear potentiometer — linear output from 2° to 358°. Really nice ones are linear from -90° to 450° to help with direction trending.
  • Gray code — has several ttl outputs which generate a bitmap from which the wind sector can be deduced.

Reed switch anemometers are probably the easiest to read, but are quite low resolution. They work well with long cables. Other types are linear (voltage or current loop), low voltage AC (with frequency proportional to wind speed) and square wave (usually generated by a photochopper).

Since most wind data loggers (even the really expensive ones used for utility-grade work) are many times less powerful than an Arduino, I've been meaning to develop a decent logger sketch.
5  Using Arduino / Project Guidance / Re: Deciphering an unknown serial feed on: February 22, 2011, 10:14:04 pm
No pattern, looks mess before and after - bit-rate is wrong.
And that's pretty much what I have to do. Thanks to all!
6  Using Arduino / Project Guidance / Re: Deciphering an unknown serial feed on: February 22, 2011, 03:06:27 pm
The 9600baud looks most promissing, but still makes little sense - is 19200 and 38k4 log also possible?
I don't think so. The Parallax receiver only supports up to 9600. Most 433MHz wireless rx/tx units go up to 2400 or 4800.
7  Using Arduino / Project Guidance / Re: Deciphering an unknown serial feed on: February 22, 2011, 02:21:37 pm
So the question is, who or what sends it?

It's one of these: Electricity Power Cost Monitor.

The module has a signal strength indicator, so you can use it to detect the sender? (neighbour, TV, elektricity meter, washing machine ...?)

Sort of. The received signal strength peaks every ~31.8s, which coincides with the Power Cost Monitor's display updating. I get signal strength traces like this:

(If that image is blocked, there more of a blog post here: on the trail of the elusive Power Cost Monitor signal)

8  Using Arduino / Project Guidance / Re: Deciphering an unknown serial feed on: February 22, 2011, 07:58:56 am
Is this RS232 or 5v logic signal?

Measure the voltage during the 32sec idle period to determine the polarity. That will remove one variable.

It's wireless, Rob. There isn't any idle period, as the antenna picks up anything it can use and turns it into characters.

9  Using Arduino / Project Guidance / Deciphering an unknown serial feed on: February 21, 2011, 09:03:49 pm
I'm trying to decode the serial wireless transmission from a 433MHz power monitor. This unit sends a short data burst about every 32 seconds. I can see data coming in, and using the Parallax 433 MHz RF Transceiver, I can filter out noise and have a fairly good idea when the data's coming in.

Unfortunately, I have no idea of the bitrate, or whether the bits are inverted, or what's being transmitted. Is there any way that, by looking at a bit stream, for me to know if I'm using the right bitrate?

Thanks in advance,
10  Community / Bar Sport / Re: Valentines Day.. on: February 19, 2011, 11:44:13 am
I made this with a LoLShield: S ♡ C.
11  Community / Bar Sport / Re: Whats with the anti-arduino sentiment? on: February 19, 2011, 09:10:10 am
I think we're all hitting relevant aspects of the issue here. One of the things I really like about Arduino is that you seldom feel like you're 'hitting the metal'. The Arduino language feels like a real programming language, while the others I've looked at (MSP430 and PICAXE) are more like strings of configuration parameters, hiding the logic of the program.

I'd far prefer to be able to understand programming logic concepts than remember specifics of particular processors. For more than half my life, I've been uselessly carrying around the ability to disassemble Z80 opcodes in my head, even though the need for me to do so evaporated more than 20 years ago.

I program Arduino for fun. My day job is engineering, so I leave the detail stuff in the office. I'm glad other people enjoy squeezing the last clock cycle out of their processors. But there is, as the old Perl mantra goes, more than one way to do it.
12  Using Arduino / General Electronics / Re: The right temperature for lead-free soldering? on: January 30, 2011, 03:13:20 pm
Lead is not the boogey-man some have made it out to be.  Don't ingest it and there are no problems.  This amounts to having the brains to wash your hands before eating and not letting kids gnaw on it.

Pretty much all elemental metals are fairly nasty to ingest. Lead's a bad one; there was a lot of lawsuits and industrial action in the early part of the 20th century from the garment makers (white lead used as a marker), painters (white lead causing wrist and leg drop) and petroleum workers (tetra-ethyl lead fumes). Lots of unfun reading in books like Markowitz, Gerald and David Rosner. Deceit and Denial. Berkeley: University of California Press, 2002.

I know I would follow the guidelines, but I can't guarantee that the people that get my stuff after me will. Having known someone whose life was blighted by lead poisoning, I don't want to take that risk.

I find it quite ironic that allegedly "green" groups are pushing CFLs, which contain mercury which is a problem, quite mobile once it gets loose in the environment, etc.

I work in the power industry. Even if CFLs are disposed in the worst way possible, the mercury released is far less than the mercury emitted by power plants needed to drive incandescents. Either way, I'm glad that domestic LED lighting is now affordable, and I'm replacing CFLs as they fail with LEDs.
13  Using Arduino / General Electronics / Re: The right temperature for lead-free soldering? on: January 30, 2011, 09:08:54 am
Given that my last reel of solder has lasted me 30 years, I don't feel too 'un-green'.
It's not a "green" thing. It's a "not wanting to have a listed neurotoxin in an uncontrolled cycle" thing. Lead's quite spiffy if you can keep it in a closed use-recycle loop, like with car batteries. The way I solder, the word control doesn't come into it ...

Anyway, with some fiddling about, I've found that 275°C/530°F has a decent balance between
  • melting the solder quickly
  • not burning off the flux before it has a chance to work its magic.

I think I had the iron too hot, hence the blobby, unwetted joints before.

Thanks for all the help.
14  Using Arduino / General Electronics / Re: The right temperature for lead-free soldering? on: January 29, 2011, 10:24:49 pm
Sorry, leaded isn't an option. I guess I'll just have to fiddle with the temperatures, thanks.
15  Using Arduino / General Electronics / The right temperature for lead-free soldering? on: January 29, 2011, 11:48:51 am
I finally caved and bought a temperature-controlled iron (a Weller WES51: yay, accurate control; boo, arcane °F temperature scale). I don't think I have the right temperatures dialled in yet. What would folks recommend for 96.3% tin, 0.7% copper and 3% silver (MG Chemicals #4900 — At the moment, I'm getting little spherical joints rather than the more familiar conical ones.
Pages: [1] 2