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1  Using Arduino / Displays / Re: ywRobot I2C LCD problem / solution on: January 02, 2013, 11:42:34 am
I have one through Terry King at Yourduino.
Mine has a PCF8574T and the I2C address is 027.

There is everything you need at

2  General Category / General Discussion / Re: Breadboard Schematics on: July 09, 2012, 09:46:03 pm
This is an interesting discussion....

I have the problem where I'm taking some 10-12 year olds through an introduction to Arduino.
I provided the school with 5 controllers,breadboard on a shield and some basic parts.
We have had 4 x 1.5 hr sessions, and 7 of the 8 brought their own kits, so I've offered a full day tomorrow in the holidays.

Does anyone have some reference material that I can pass onto these guys, to help teach this Schematic to Breadboard.?

Obviously back when I learnt it, microcontrollers disn't exist, and things that had heaters were used.
Fritzing is very useful (when you have limited time to put together the circuit, and teach the examples), but it isn't the end.

3  Using Arduino / Installation & Troubleshooting / Re: IDE-1.0 IS BUGGY! on: February 24, 2012, 05:33:50 pm
and why the file extension change?
I think you will find a setting under preferences (from memory) that 'changes to .ino'.

This may resolve this situation you have.

Personally I haven't found it slower, but you can still download and use ver 023.
As I understand some code needs changing because they have changed some keywords in (Wiring.h ???).
I found it when trying to load an old sketch that worked in previosu versions, using Ver 1.0 into my Nunchuk controller Robot.

In the end I went back to 022.

4  Topics / Robotics / Re: Dagu Rover 5 chassis robot demo on: February 23, 2012, 10:58:53 pm
I heard of one guy using the guts of an optical mouse, in a sumobot.
He simply detected if he was moving backwards while he was driving the wheels forward and acted on it.

This might help overcome the slippery surface issues.

5  Topics / Robotics / Re: Balancing unicycle help on: February 23, 2012, 10:54:09 pm
Thanks Lefty

I have fallen into it before so should have known.

Hopefully he has a means to NOT remove the deadmans switch now.

6  Topics / Home Automation and Networked Objects / Re: EtherTen + Ridiculous code on: February 23, 2012, 02:31:51 am
For question 1, you could use an optocoupler in series with the relay.
(i missed what voltage it is, etc) this could then feed back the state.

You simply have the contacts in parallel, so that it turns on the relay from either the PIR, controller, or a switch.

7  Using Arduino / Motors, Mechanics, and Power / Re: windmill controller on: February 23, 2012, 02:18:45 am

Do you have any figures on the force required to pull the handle (or tail cord), or does it depend on wind speed.

You could use a series of weights to work it out.

One other thought is a 'dead-drop' where the cord has a weight large enough to furl it.
You attach it via a trigger mechanism, and when its too much, you operate the trigger, which releases the weight.
Remote boot release mechanisms are very powerful, or for a lighter trigger, remote car door lockers.

if you have constant power there are quite a few holdback devices, that are small magnetic locks, and when the power goes it releases (fail to safety).
This would probably be easier than a winch.

8  Using Arduino / Motors, Mechanics, and Power / Re: recirculating/flyback diodes on: February 22, 2012, 11:52:05 pm
The use of flyback (or other terms) diodes is an interesting subject.
These two links talk about relays, but as you can see, using a simple diode can increase the amount of time a coil takes to 'release it's hold'. and

There was another very good one, that I didn't save (wish I had) showing the various waveforms.
it appears that inserting a Zener diode (about the same voltage as the energising supply) in series with the diode, will stop the back emf, and not result in am increase in the effective Off time.

Until now I was under the assumption that the diode was it, but maybe not so.
For a stepper, this may be important to the top speed.

9  Topics / Robotics / Re: two connected Arduinos on: February 22, 2012, 11:32:49 pm
Sounds similar to what I was planning.
I agree that RS422/485 is the easiest connection method, which allows long distance and reasonably high speeds, over dodgy cable.
You will need to watch that both legs are balanced relative to earth though.

I'm interested if you have done the code, or settled on a protocol yet.

10  Topics / Robotics / Re: Balancing unicycle help on: February 22, 2012, 11:20:04 pm
Correct me if I'm wrong but when you digitalread the pin, you get a HIGH or LOW (

k4 = digitalRead(deadmanbuttonPin);  //this is needed - if you let go the motors both stop for your own safety

but then you do this with the result

//if not pressing deadman button on hand controller - cut everything
   if (k4 < 1) {
    level = 0;
    Steer = 0;
    Motor1percent = 0;

should it not be :-
//if not pressing deadman button on hand controller - cut everything
   if (k4 = LOW) {         (// or HIGH if you are using the internal pullup)
    level = 0;
    Steer = 0;
    Motor1percent = 0;

11  Topics / Device Hacking / Re: Wii Motion Plus outputs '0' only on: February 05, 2012, 04:13:28 pm
Hi w1ndf4k3r.
Can you double check and make sure that SCL (clock) is connected to pin A5, and SDA (Data) is connected to pin A4 please.
The MP (and NC) use 3.3v, so please ensure your Arduino board is providing the 3.3 volts to the Power pin of the MP, it is also necessary to ensure the ground is connected to the Arduino board as well.

I pulled my MP apart and soldered directly to the pcb, rather than making a plug.

There are different initialisation codes when the MP is NOT connected in series with the NC.
I haven't tried the code with a MP only, so I can't suggest what would happen, and freezing is quite likely.

The resistors aren't a choice, they are there to ensure the line is pulled up, rather than randomly floating.
The I2C device (in this case the MP or NC) pull down this line to pass data.

Hopefully these suggestions will help you.

12  Topics / Device Hacking / Re: Making a Nunchuck connect to a rc transmitter via trainer cord - help with code on: August 16, 2011, 05:15:09 am
If you do a search you should find a post regarding a nunchuk that someone was having trouble with.
I posted the code I used to interface a nunchuk (wireless and corded) to an Arduino.

13  Topics / Home Automation and Networked Objects / Re: PoolDuino - Automate my pool with Arduino on: August 15, 2011, 11:59:53 pm
Regarding your pressure sensor.

I read somewhere that electronic sensors don't like moisture, and the thought was to put them on the sealed side of canister.
To save our water pump stopping and starting everytime the tap is turned on, we use a pressure pot on the pump. Basically its a big metal can with a rubber bladder, that you put x pressure air into one side, and the other side is tapped onto the water line.
When the water pump is off the bladder supplies an amount of water until the pressure drops low enough for the pump to kick in.

I was thinking that if you had a similar device, and measured the air pressure, it would ensure no moisture got near it.

14  Using Arduino / Project Guidance / Re: Hacking My Digital Clock on: August 04, 2011, 06:45:00 pm
If your clock has the display part seperate from the electronics, you can probably just replace the electronics.

Usually the displays are multiplexed.
All the segments are tied together, and they just strobe each digit.
The eyes persistance makes it look like they are all on.

Some displays are common anode, some are common cathode.
Assumming you are still keen, you should try to establish what the supply voltage is, and work from there.

15  Using Arduino / Networking, Protocols, and Devices / Re: Long Range Communications on: August 03, 2011, 07:38:43 am
Here downunder my broadband is via a 2.4 GHz link.
It uses a low power unlicenced 'bullet' with a 24db Gridpack antenna over a 32Km link at 2MB (limited to this).
As far as I am aware the other end is reasonably omni directional, while my end is very narrow.

Antenna is :-

Bullet is :-

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