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226  Forum 2005-2010 (read only) / Development / Large LED display for temperature. on: October 11, 2009, 04:01:41 pm
Hi,

A am looking to make a large LED display for our local community swimming pool - numbers may be 150 to 300mm tall with the units at the end ..... so something like 28.4~C (~ = degree symbol).  Could be segment or matrix.

I guess this has been done before but any tips on how to achieve this in a simple, cost effective manner would be great  smiley

Cheers
227  Forum 2005-2010 (read only) / Interfacing / Remote SD card breakout PCB on: November 24, 2010, 01:17:30 pm
Hi,

I am hoping to make a little breakout PCB so that I can remotely mount an SDcard away from a microSD shield.... I'm not great at electronics but I thought perhaps this simple task should be possible for me :-)  Anyway, I have sketched out how I think it should work in Eagle but was wondering if anyone with keen eyes can spot any problems?

The basic aim is to run wires from the microSD card slot on the shield to the SD card slot on the breakout - allows a bigger more robust card to be used and mounted where I can get at it :-)

Any thoughts appreciated.....



228  Forum 2005-2010 (read only) / Interfacing / Re: Analog value for IR Photodioide? on: October 26, 2010, 03:01:47 pm
Thanks for your help - very much appreciated.  My ultimate goal is to record when a wood burner is on and to what degree (without contact) - I figured infra red is the way to go but I need to do some testing - now that I can get some sort of sensor output I can see how it might help me record the info I'm looking for.

Thanks again :-)
229  Forum 2005-2010 (read only) / Interfacing / Re: Analog value for IR Photodioide? on: October 25, 2010, 04:54:34 pm
No change but I tried the same setup on a 328 board (I was using a 168) and now I'm getting results :-)  The value is high when the is no IR and low when there is... is this right?

Not sure about the 168 board - it should work the same I guess?
230  Forum 2005-2010 (read only) / Interfacing / Re: Analog value for IR Photodioide? on: October 25, 2010, 04:22:54 pm
Ooops..

Now wired as below but I get the same result?

PhotoDiode Short leg to Arduino Analog pin 0
PhotoDiode Long leg to Arduino GND
PhotoDiode Short leg to Arduino +5v using 10K ohm resistor

231  Forum 2005-2010 (read only) / Interfacing / Re: Analog value for IR Photodioide? on: October 25, 2010, 03:55:46 pm
Hi RuggedC,

Thanks for the pointer - I have tried it but I just get values in the serial which slowly fall from about 500 with no response to anything?

May I check the below with you - sorry, very basic.

PhotoDiode Long leg to Arduino Analog pin 0
PhotoDiode Short leg to Arduino GND
PhotoDiode Long leg to Arduino +5v using 10K ohm resistor

Using this code:

Code:
void setup() {
  Serial.begin(9600);
}

void loop() {
  int sensorValue = analogRead(0);
  Serial.println(sensorValue, DEC);
  delay(1000);
}
232  Forum 2005-2010 (read only) / Interfacing / Analog value for IR Photodioide? on: October 25, 2010, 01:30:35 pm
Hi, I have been trying to set up an arduino to measure Infra Red  (how much) using an Osram SFH 203 FA but with ZERO results !!

http://uk.farnell.com/osram/sfh203-fa/photodiode-ir-filtered/dp/1212743

I have tried a few variations but basically I am using the AnalogReadSerial sketch with the photodioide positive going to arduino analog pin 0 and the photodiode negative going to arduino GND - clearly wrong?  I just get a bunch of values the same as if nother is connected.... any pointers would be great  smiley
233  Forum 2005-2010 (read only) / Interfacing / Re: HSM-20G analog temperature/humidity sensor on: October 01, 2010, 03:49:47 pm
Hi Itsthemedication,

Thanks for sharing your work - very much appreciated.  I have now had a go and finally got the sensor working :-)  On my arduino 328 it outputs sensible figures but when I load up onto a 168 the figures are quite a bit out - any idea why this should be?

328             168
52.2 %RH    83.3 %RH
25.4 deg C  36.8 deg C

52.2 %RH    83.3 %RH
25.4 deg C   36.8 deg C

52.4 %RH    83.3 %RH
25.4 deg C   36.8 deg C
                  

        
        

        
        
234  Forum 2005-2010 (read only) / Interfacing / Re: HSM-20G analog temperature/humidity sensor on: February 23, 2010, 06:01:29 pm
Fab again - many thanks.

I think the temp part of the sensor is duff as the value goes from 908 down to 892 when droping from 22C to 0C which is less than 1 degree resolution!!  I guess I'm stuck with just RH with this sensor.... but learnt loads so thanks for your time and knowledge :-)
235  Forum 2005-2010 (read only) / Interfacing / Re: HSM-20G analog temperature/humidity sensor on: February 23, 2010, 06:57:54 am
Ahhh-ha  I got the temp value to respond by engaging the pullup resitors on that pin - I just need to figure the formula out now as dividing the analogread value by 50 is clearly wrong !!!
236  Forum 2005-2010 (read only) / Interfacing / Re: HSM-20G analog temperature/humidity sensor on: February 23, 2010, 04:43:53 am
Hi ArduinoM,

Thanks for posting - I just learned a whole lot about excel and arduino :-).

Got RH working well with the code below based on a linear trendline (to make the maths easy) and the data provided in the data sheet.  Now for some reason I don't understand the temperture outputs on the data sheet are given in ohms and the output from arduino is showing 1023 which is presumably 60C or higher...?  One thing is for sure - it's cold and wet here today.... any ideas?

Code:
int tempsense = 0;
int rhsense = 0;
int temp = 0;
int rh = 0;

void setup() {
  Serial.begin(9600);
}

void loop() {
 
 tempsense = (analogRead(1));
 rhsense = (analogRead(2));
 temp = (tempsense/50);
 rh = ((30.855*(rhsense/204.6))-11.504);
 
 Serial.print("Temperature: ");
 Serial.print(temp);
 Serial.println(" C ");
 
 delay(100);
 Serial.print("Humidity: ");
 Serial.print(rh);
 Serial.println("% ");
                                            
 delay(1000);
}
237  Forum 2005-2010 (read only) / Interfacing / HSM-20G analog temperature/humidity sensor on: February 22, 2010, 04:57:02 pm
Hi,

I recently bought one of these: http://www.seeedstudio.com/depot/humidity-temperature-sensor-module-p-75.html?cPath=6 expecting that I would be able to work it out from the data sheet once I had it in my hands :-)

Looks like I'm wrong - I'm simply trying display the output in degrees C and %RH but I can't find the relevant info on how to convert the numbers.

Has anyone else had success with this sensor?

Cheers.
238  Forum 2005-2010 (read only) / Interfacing / Re: Sensitron SHT15 and SHT75, what is the difference? on: June 23, 2010, 04:40:54 am
I think its more than just size :-)  Energy consumption is much lower for sure.

This is what they say:

SHT21, the new humidity and temperature sensor of
Sensirion is about to set new standards in terms of size
and intelligence: Embedded in a reflow solderable Dual
Flat No leads (DFN) package of 3 x 3mm foot print and
1.1mm height it provides calibrated, linearized signals in
digital, true I2C format.
With a completely new designed CMOSens® chip, a
reworked capacitive type humidity sensor and an
improved band gap temperature sensor the performance
has been lifted even beyond the outstanding level of the
previous sensor generation (SHT1x and SHT7x). For
example, measures have been taken to stabilize the
behavior at high humidity levels.
Every sensor is individually calibrated and tested. Lot
identification is printed on the sensor and an electronic
identification code is stored on the chip – which can be
read out by command. Furthermore, the resolution of
SHT21 can be changed by command (8/12bit up to
12/14bit for RH/T), low battery can be detected and a
checksum helps to improve communication reliability.
With made improvements and the miniaturization of the
sensor the performance-to-price ratio has been improved
– and eventually, any device should benefit from the
cutting edge energy saving operation mode. For testing
SHT21 a new evaluation Kit EK-H4 is available.

SHT15
Energy consumption: 80uW (at 12bit, 3V, 1 measurement / s)  
RH operating range: 0 – 100% RH
T operating range: -40 – +125°C (-40 – +257°F)
RH response time: 8 sec (tau63%)
Output: digital (2-wire interface)

SHT21
Energy consumption: 3.2uW (at 8 bit, 1 measurement / s)
RH operating range: 0 – 100% RH
T operating range: -40 – +125°C (-40 – +257°F)
RH response time: 8 sec (tau63%)
Output: I2C digital, PWM and SDM/analog Volt interface
239  Forum 2005-2010 (read only) / Interfacing / Re: Sensitron SHT15 and SHT75, what is the difference? on: June 22, 2010, 03:26:53 am
Looks like the SHT21 will be available here soon: http://misenso.com/2010/05/arduino-humidity-sensor-sht21/  I emailed and was told next week :-)
240  Forum 2005-2010 (read only) / Interfacing / Re: Shield for Tx/Rx RS485? on: June 21, 2010, 12:19:18 pm
Maybe this is worth a look too?

http://www.dfrobot.com/index.php?route=product/product&path=35_39&product_id...
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