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106  Using Arduino / General Electronics / Re: Looking for Solar Charger circuit to charge 6x1.2v batteries with protection on: July 21, 2012, 11:53:51 pm
Thanks for that Doc

I am in Christchurch, New Zealand - so not a lot of sun here and even worse in the position where the panel would be placed.

I will try to find some more details about the cells you mentioned and see if I can source them online


107  Using Arduino / General Electronics / Looking for Solar Charger circuit to charge 6x1.2v batteries with protection on: July 21, 2012, 11:30:50 pm
Looking for Solar Charger to charge 6x1.2v batteries with over/under protection?

I have been looking around and there is a lot of information around on solar charges but I am looking for something that can charge 6 x 1.2v  Ni-MH Batteries.

I also want it to handle over and under voltage protection.

Obviosuly this is not just a charger as I am wanting to run my Arduino on the batteries during the dark and when it is light the solar charger will charge the batteries and run the arduino.

Any circuits you can recommend.

108  Using Arduino / Networking, Protocols, and Devices / Re: RF Super Heterodyne Wireless Receiving Module TDL-9927 - What pin does what? on: July 21, 2012, 03:43:26 pm
Here is where I bought the device


Model: TDL-9927
- Material: PCB
- Working Frequency: 315Mhz
- Oscillation Mode: Surface acoustic wave (SAW)
- Bandwidth: 2MHz
- Modulation Systems: ASK/OOK
- Sensitivity: -100dBm
- Transmission Rate: < 5Kbps
- Antenna Length: 24mm
- Working Voltage: DC 3V~5V
- Working Current: <= 5.5mA
- Ideal for wireless remote control device, burglar alarm security system etc.

I found a document online in Chinese that is for this board (aparantly)

I tried to translate the document but google returns nothing for it - also copying to the clipboard did not work for me.

But from the diagram we have this

I am about to give it a try hope it is accurate

109  Using Arduino / Project Guidance / Taking arduino circuit and making it a small dedicated project on: July 21, 2012, 12:49:56 am
I am working on a simple pulse counter for electricty monitoring in my home.

My device/circuit will/does contain the following

* Serial Bluetooth Module - bought off for $6.60 USD
* Schmitt Trigger - 40106
* Light Dependant Resister
* Possibly a Real Time Clock - Not sure if I need it yet - may just use the PC clock when saving data.
* Arduino Duemilanova

I want to make the hardware small (not SMD but small) - low power and self contained so I want to remove the Arduino itself and use something smaller, but something that still works with Arduino code.

So my question is how to shrink this down?

Could I look at an ATTINY85?  I think this does not have a UART so my TX/RX is a problem on the Bluetooth Module - Am I correct? - I found this video

Could I look at a simple ATMega 168 or similar as seen in this video

I am currently needing 3.3v and 5v but that could be reduced to the 3.3v alone ( the schmitt trigger is a 40106 which can run at 3v - currently 5)

I need one digital input which triggers an interrupt when it changes.

If anyone has any ideas I would really appreciate them


110  Using Arduino / Networking, Protocols, and Devices / I need to add a small aerial to my Bluetooth module from China on: July 20, 2012, 11:24:00 pm
Hi all

I have a cheap bluetooth module that I bought from China on Deal Extreme.

Now it comes with a small track at one end of the PCB that is an aerial.

My problem is that I am wanting to use this module to measure my power usage so it must go in the cabinet with the power meter. The power meter is on the outside of the house in a metal unit.

So I need an aerial to pass the bluetooth signal to my PC to capture data.

Does anyone know how to create a simple external aerial for a device like this?

I tried putting a 20cm peice of wire onto the aerial on the PCB but then the device was not detected at all - so I need to understand how I can proceed.

Any help is really appreciated

111  Using Arduino / Sensors / Re: Home Energy Monitoring via flashing LED on Meter on: July 20, 2012, 06:28:33 pm
i think it might be a good idea to pull down the other 5 inputs...
because: a floating input wastes power...  smiley

Thanks for the advise.

I take it that pulling it down means connecting a resister to GND?

If so how do I calculate the correct value for a resister to GND?

Should I be looking at the datasheet for this type of Information? I am a newbee and want to learn so if you can point me to a web site that would be great, even just letting me know a 10K resister etc would.

112  Using Arduino / Networking, Protocols, and Devices / Re: RF Super Heterodyne Wireless Receiving Module TDL-9927 - What pin does what? on: July 19, 2012, 08:59:30 pm

I found a PDF appliation circuit for the RX3310A so was going to try to trace the pins from the chip to the external pins.

What is the decoding chip for ? The site talks about Remote Controls etc..

Is this PT2272 chip on the back of the circuit board?  I am at work so can't look at the moment.

113  Using Arduino / Networking, Protocols, and Devices / RF Super Heterodyne Wireless Receiving Module TDL-9927 - What pin does what? on: July 19, 2012, 02:05:59 pm
I have purchase a RF Super Heterodyne Wireless Receiving Module TDL-9927 from china.

Problem is there is no details on which pin does what!

The model is TDL-9927

There are lots of sellers selling these and none show which pins are which.


114  Using Arduino / Sensors / Re: Home Energy Monitoring via flashing LED on Meter on: July 16, 2012, 03:45:57 am

I have started from scratch as far as the hardware goes - the software is the same as earlier in this post history for this topic.

The image contains most of the hardware but I will repeat it here:

1 x 4.7K OHM Resister
1 x LDR (10M in the dark, 0 in the light)
1 x 40106 Schmitt Trigger - Inverting.
Hookup Wire

This along with the original code from above is nicely capturing the pulses from LED on arduino board, and also a torch.

I will next need to do some testing with the actual live meter.

Next problem is the meter is in a steel box on the outside of the house - I need to figger out a wireless solution but am happy at the moment.

115  Using Arduino / Sensors / Re: Home Energy Monitoring via flashing LED on Meter on: July 15, 2012, 04:50:46 am
u can use a nand schmitt trigger too...
F  = ((T) NAND T)=F
T  = ((F) NAND T)=T

Thanks I thought it should work but I will buy some straight triggers tomorrow.

a LDR sounds good too...

I will try this and see if this is better or not - I guess with a volage dividor and a schmitt trigger it would be good if it is fast enough.

i still think that the arduino pin has something like a schmitt trigger builtin...

No idea myself.

what does the scope say?

I will try tomorrow and post results here

did u try that debounce library? i guess those blinks r 30msec long...
even if u tell the debounce library to skip 40msec, u could detect >10Hz...
after 160secs u could have 1kWh (max)...
that limits ur load to 22.5kW (22 vacuum cleaners)...

No I did not since my code is using interrupts and the debounce is not.

I have seen it years ago and was thinking about it a week or two back. Amazing what one can monitor but toilet flushes do not interest me.


Thanks for your help

116  Using Arduino / Sensors / Re: Home Energy Monitoring via flashing LED on Meter on: July 15, 2012, 12:56:20 am
OK - I am getting myself lost here.

My TSOP136 IR Receiver is pulsing like this

1 pulse
2 pulses
1 pulse
2 pulses

and sometimes

1 pulse
1 pulse
2 pulses

Now the RED LED  is pulsing just one per second. So that should be

1 pulse
1 pulse
1 pulse

a Red LED is around the 650 nm wave length and the IR Receiver I assume since it is IR is more like 875 or so. It is oviously pickin up the flash but maybe in this case it is too smart since it says in the docs

"PIN Diode, pre-amplifier, AGC, pass Filter and demodulator"

Would I be better off with a LDR feeding into a Schmitt Trigger?

I went out and bought the wrong schmitt IC today at the local JAYCAR - I ended up buying a 4093 QUAD 2-INPUT NAND SCHMITT TRIGGER CMOS IC instead of 74C14 HEX SCHMITT TRIGGER CMOS IC

Do you think the lack of a Schmitt Trigger could be causing this double counting sometimes?

117  Using Arduino / Sensors / Re: Home Energy Monitoring via flashing LED on Meter on: July 14, 2012, 04:18:03 am
is it "1600 times for 1KWh"...?  smiley

... or even kWh  smiley-cool


1600 Imp KwH

Or something like that - it is dark. So 1600 flashes per Kilo Watt Hour!

Thanks for the tip on the Schmitt Trigger - RIDDICK

118  Using Arduino / Sensors / Home Energy Monitoring via flashing LED on Meter on: July 14, 2012, 12:54:38 am
I have seen some posts around the net on Monitoring your home electricity meter by counting the flashes on the LED that most have.

In my case it is a red led that flashes 1600 times for 1 KW.

I have simulated this setup with 2 arduino's

I am using a TSOP4136 IR Receiver

A the moment the IR Receiver's out is fed into pin 3 on the arduino duemilanove.

I am using this code

/*-----( Declare Constants )-----*/
#define LEDPIN    13  // The onboard LED

int Counter = 0;

/*-----( Declare Variables )-----*/
int  switch_state;  /* Holds the last digital value */
int  LightAnalogValue; /* Holds the last analog value */
unsigned long pulseCount = 0;  // Counts power pulses in interrupt, 1 pulse = 1 watt
unsigned long pulseTotal = 0;  // Total power used since the sketch started
volatile int pulseFlag = 0;

void setup()   /*----( SETUP: RUNS ONCE )----*/
       /*Initialize INT0 for accepting interrupts */
     PORTD |= 0x04;
     DDRD &=~ 0x04;
  pinMode(LEDPIN, OUTPUT);
  Serial.begin(9600);          // Enable the Serial data output
//Enable interrupt for light sensor on Digital 3

  attachInterrupt(1, Pulse, FALLING);
}/*--(end setup )---*/

void Pulse() // routine called when light sensor interrupt is triggered
    pulseFlag = 1;

void loop()

  if (pulseFlag == 1)
    logPulse();  //if interrupt caused by light sensor, count the pulse

void logPulse() //count a pulse from the light sensor
   pulseCount ++;
   pulseFlag = 0;
   Serial.print("Pulse Count: ");
   attachInterrupt(0, Pulse, LOW); 

Now this seems to work but looking with a scope the signal is noisy and it is not a nice square wave - almost a sine wave.

What is the best way to clean this up and make it a square wave?

119  Using Arduino / Project Guidance / Sending data with a LASER from PC/Arduino to another Arduino/PC on: July 05, 2012, 02:59:40 pm
I am interested in sending Data from a PC to another PC or Arduino to Arduino via a laser.

I found this video that shows how it is done but no code/schematic.

Has anyone found a more detailed example with schematic and code?

I will try this weekened to reproduce what I have seen in the video but if someone knows of a tutorial that does this already it would help me a lot.


120  Topics / Science and Measurement / Re: personal weather station on: July 01, 2012, 06:46:18 pm
What do You use for sky conditions? Which sensors are You using?

Sorry for the delay in getting back to you.

I am using a Cloud Sensor from

This is a great device as it tells me if it is clear or cloudy (or partly cloudy), and I have used it along with my other weather station data to detemine if it is drizzling, raining, snowing etc...


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