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181  Using Arduino / Project Guidance / Re: Questions about Arduino on: October 28, 2012, 12:19:22 pm
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Which is better for my case, Arduino UNO or Arduino Leonardo ?

A 'no brainer'; The Leonardo is a significant upgrade from the Uno, including more pins. Here's the kicker: it costs less. Better for less, how often does that happen? Now that I think of it, perhaps, in the world of electronics, that might not be such a rare occurrence.

Quote
I can remove the ATmega chip and use it in a PCB ?

If you get the Uno and the ATMega MC is ia DIP(dual inline package), yes you can. If the Uno you get has the ATMega MC as a SMD(surface mounted device, you can't just pop it out and put it into another board. It could be removed and solderred into another board but it would be tricky and difficult and I think, pointless.

 - Scotty
182  Using Arduino / Motors, Mechanics, and Power / Re: Motorizing a valve, which of this two options is better? on: October 26, 2012, 06:36:35 am
Hey travis12,
Quote
use a cheap 11 Kg-cm servo
Where'd you get it? The power and gears sound impressive but I saw one review on Youtube that was interesting.

- Scotty
183  Using Arduino / Motors, Mechanics, and Power / Re: What to use for locking? on: October 25, 2012, 05:56:39 am
Recently came across this:http://www.sciplus.com/category.cfm/category/144. Perhaps useful to you. - Scotty
184  Using Arduino / Programming Questions / Use of other Atmel micro controllers on: October 23, 2012, 09:20:05 am
A project I am working on is a solar tracker. It uses 4 analog inputs and one digital ouput. I thought it'd be cool if it could be controlled by an inexpensive 8 pin device such as the ATTiny85. What puzzles me about using a micro controller without the aid of the Arduino platform is troubleshooting the code which is normally done on an Arduino using the serial monitor. How is this done? - Scotty
185  Using Arduino / General Electronics / Re: Need a gas valve to switch and select outlet air flow from two inlets sources on: October 23, 2012, 08:56:15 am
That may be expensive in that it might be an uncommon valve. Perhaps it would be better to use two valves and 'Y' their outputs together. You may find a solenoid valve you can use in the automotive industry. An EVAP solenoid http://www.amazon.com/ACDelco-214-1685-VALVE-ASM-EVAP-BRACKET/dp/B0049BROCI is one that handles fumes of the fuel system. I recently discovered two valves on a vehicle that I was working on to have variable ports actuated via stepper motors. - Scotty
186  Using Arduino / Project Guidance / Re: Using a stepper motor to operate a window vent on: October 16, 2012, 06:22:08 am
Quote
... or look for an electric window lifter from any local car breakers.

Ditto! Particularly the type that are arm worm gear driven in that the position of the vent will be held when the system is static. Come to think of it, any window regulator drive system will hold it's position. - Scotty
187  Using Arduino / Project Guidance / Re: controlling a actuator by canbus on: October 15, 2012, 11:00:31 am
Hello. It took me some digging to even find out what you are talking about. I searched for delphia actuator. Second in the list of hits for that search was your own post. A search for delphi actuators was much more rewarding. Now I knew what a delphi actuator is and I guessed that version 1 (vi) was meant to read 'via'. So then I did a search for delphi actuator arduino and came up with this: https://www.google.com/search?source=ig&rlz=1G1TSHB_ENUS352&q=delphia+actuator&oq=delphia+actuator&gs_l=igoogle.3..0i22.775.10385.0.11551.14.13.0.1.1.0.301.1353.12j3-1.13.0...0.0...1ac.1.-bYwBAoCeKw#hl=en&sugexp=les%3B&gs_nf=3&gs_mss=delphi%20actuator&tok=r6YmgDil_cnSI-ulftkhgg&pq=delphi%20actuators&cp=23&gs_id=16&xhr=t&q=delphi+actuator+arduino&pf=p&tbo=d&rlz=1G1TSHB_ENUS352&sclient=psy-ab&oq=delphi+actuator+arduino&gs_l=&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.&fp=936fd8e854666be7&bpcl=35277026&biw=1280&bih=743

Perhaps the reason you didn't get a response is that noone knew what you were talking about.

- Scotty
188  Using Arduino / Project Guidance / Re: IR beam break detection on: October 15, 2012, 08:57:06 am
I'm only using one Arduino. The circuitry is as shown in a previous post of mine in this thread. - Scotty
189  Using Arduino / Project Guidance / Re: IR beam break detection on: October 15, 2012, 07:40:51 am
terryking228, I'm not using any libraries right now. My immediate goal is to detect an IR beam break. Later that working hardware and code would be incorporated into a final project sketch. I suppose you could say I'm sending and receiving at the same time but not via the Arduino in that the 38khz functions are autonomous in the sending and receiving devices. The sketch enables the sender to send a stream of 38khz pulses for a brief time and checks the receiver's digital output. Perhaps I don't understand what you are asking. - Scotty
190  Using Arduino / Project Guidance / Re: IR beam break detection on: October 14, 2012, 10:21:09 am
I've failed to get this circuit working.



Code:

#define PIN_IR_DETECT 4 //tied to output of IR detector
#define IR_TRANS_PULSE_PIN 5 //tied to DATA pin of transmitter
unsigned long PULSE_WIDTH; //pulsewidth of IR receiver output
boolean IR_REC_STATUS; //is IR receiver output active LOW or HIGH?


void setup()
{
  Serial.begin(9600);
  pinMode(IR_TRANS_PULSE_PIN, OUTPUT);
  pinMode(PIN_IR_DETECT, INPUT);
  analogWrite(IR_TRANS_PULSE_PIN,127);//turn IR emitter on 1msec, off 1 msec
 
}

void loop(){

 
  PULSE_WIDTH = pulseIn(PIN_IR_DETECT, LOW);
  IR_REC_STATUS = digitalRead(PIN_IR_DETECT);
 
  Serial.print ("Pulse Width =  ");
  Serial.print (PULSE_WIDTH);
  Serial.print ("      IR Receiver Status =  ");
  Serial.println (IR_REC_STATUS);
 
}





I tried two TSOP1738 receivers. Due to the opposite digital reads of their outputs, I suspect one is bad. I read the output to the DATA pin of the transmitter with a meter (has frequency/duty function)and verified that the frequency is 1khz with a duty cycle of 50%. The output of the serial monitor is below.

Code:
Pulse Width =  0      IR Receiver Status =  0
Pulse Width =  0      IR Receiver Status =  0
Pulse Width =  0      IR Receiver Status =  0
Pulse Width =  0      IR Receiver Status =  0
Pulse Width =  0      IR Receiver Status =  0
Pulse Width =  0      IR Receiver Status =  0
Pulse Width =  0      IR Receiver Status =  0
Pulse Width =  0      IR Receiver Status =  0
Pulse Width =  0      IR Receiver Status =  0
Pulse Width =  0      IR Receiver Status =  0


Pulse Width =  0      IR Receiver Status =  1
Pulse Width =  0      IR Receiver Status =  1
Pulse Width =  0      IR Receiver Status =  1
Pulse Width =  0      IR Receiver Status =  1
Pulse Width =  0      IR Receiver Status =  1
Pulse Width =  0      IR Receiver Status =  1
Pulse Width =  0      IR Receiver Status =  1
Pulse Width =  0      IR Receiver Status =  1
Pulse Width =  0      IR Receiver Status =  1
Pulse Width =  0      IR Receiver Status =  1
Pulse Width =  0      IR Receiver Status =  1
Pulse Width =  0      IR Receiver Status =  1
Pulse Width =  0      IR Receiver Status =  1


Pulse Width =  6295      IR Receiver Status =  1
Pulse Width =  220      IR Receiver Status =  1
Pulse Width =  214      IR Receiver Status =  1
Pulse Width =  220      IR Receiver Status =  1
Pulse Width =  220      IR Receiver Status =  1
Pulse Width =  220      IR Receiver Status =  1
Pulse Width =  214      IR Receiver Status =  1
Pulse Width =  220      IR Receiver Status =  1
Pulse Width =  220      IR Receiver Status =  1
Pulse Width =  220      IR Receiver Status =  1
Pulse Width =  220      IR Receiver Status =  1
Pulse Width =  220      IR Receiver Status =  1
Pulse Width =  220      IR Receiver Status =  1
Pulse Width =  218      IR Receiver Status =  1
Pulse Width =  220      IR Receiver Status =  1
Pulse Width =  220      IR Receiver Status =  1

The first two groups of text are the results of plugging in one receiver then the other. The last group is the result of no receiver installed leaving pin 4 of the Arduino floating. That last group indicates to me that pulseIn functions.

Something that I observed while viewing the serial monitor confuses me. When either receiver is installed the serial monitor updates about once every second. When not installed the data on the serial monitor scrolls very quickly as if it's updating as fast as the sketch allows.

Chagrin, I would rather have used those type of receivers. Wish I would have know about them.

terryking228, Those do look nice but, in this case, a bit pricey for me especially considering shipping costs when compared to a component that costs less than $2 and free shipping if you don't mind the wait. For a project that demanded reliability I would spend the money for peace of mind.

Thank you all for your replies. Got any ideas on what is going on here? - Scotty

191  Using Arduino / Project Guidance / IR beam break detection on: October 12, 2012, 05:59:27 pm
Hello all.
One of my ongoing projects is staircase lighting using an Arduino Uno and a TLC5940. The trigger at the top of the staircase will be a PIR sensor. At the staircase bottom the trigger will be an IR beam break; the receiver of the beam will be a TSOP1738. Originally I used the IR library for the IR sender but found that the TLC5940 library uses one of the timers that the IR library uses to output a 38khz signal to an IR led. I turned to a 555 timer to generate that frequency but couldn't maintain a steady 38khz. I think the tolerance of the 555's external components that I used was the reason for that. So I purchased a Wrobot Digital 38KHz IR Transmitter (image below). I couldn't find out very much about it's operation. I think it outputs a 38khw frequency as long as the data pin is held high; at least that's what the illuminated onboard led when the data pin is held high might indicate.

The Vishay TSOP1738, as I understand it, will not indicate seeing a 38khz light signal (output pin going low) if the signal is a continuous stream of pulses. What I read from the data sheet (below) "Burst length should be 10 cycles/burst or longer. After each burst which is between 10 cycles and 70 cycles a gap time of at least 14 cycles is necessary", in my mind, confirms that.

I think what might work is to turn the data pin of the sender high and low at a frequency of 1kz which would output bursts of 38 cycles, which is within the parameters of the receiver data sheet. Theoretically I should see a 1kz frequency on the TSOP1738 output pin. I think I could then use pulseIn(pin, value, timeout) to detect a beam break.

Do you think I'm on the right track here? Thanks - Scotty

http://www.emartee.com/Images/websites/emartee.com/42200.jpg

http://www.robokits.co.in/datasheets/tsop17xx.pdf
192  Using Arduino / General Electronics / Re: Servo cables on: October 04, 2012, 06:14:02 am

These what you are looking for?
http://www.pololu.com/catalog/category/19

I recently purchased some from here because I wanted to purchase the tool for them and wasn't able to find the tool elsewhere. I tried to avoid a purchase from here because I felt I was getting whacked on shipping but in the end had to bite the bullet. - Scotty
193  Using Arduino / General Electronics / Transistor base resistor calculations on: October 03, 2012, 10:33:43 am
Hello all. I'm building a spreadsheet to calculate the base resistor value to be used when employing a transistor as a switch. I've selected a 2N3904 as an example. Collector current would naturally be dependent on the load being driven; my selection of 100ma is the high end rating for the 3904. The 'Base Signal Voltage' is what would normally be expected from an Arduino output. Vbe and Hfe were obtained from the manufacturer's data sheet http://www.fairchildsemi.com/ds/MM/MMBT3904.pdf.

Below is the formula I used and the resulting calculations.

Is the formula correct and are my calculations correct for this device under the conditions given?

In my internet probing of this topic I've come across some suggestions that fudging various values (such as doubling Ic) ensures that the transistor is saturated. What are your suggestions, if any, regarding that?

Thanks - Scotty


Base resistance =                
               
(Base Signal voltage – voltage drop aka Vbe(sat) / (Collector current / Beta aka Hfe)               
               
               
      Required Collector Current      0.1A
            Base Signal Voltage           5v   
            Voltage Drop  Vbe(sat)      0.65v   
                         Beta (Hfe)           30   
                                    Ib           0.003333333A   
          
               
                  Base resistor value      1305   ohms
194  Using Arduino / General Electronics / Re: Voltage & current regulator on: October 01, 2012, 11:20:38 am
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The question I have is why are you planning on using this?

Below are my calculations using the 10mm leds with recommended voltage & current.

circuit voltage   led current (A)   led voltage drop    # leds   voltage drop across #leds   resistor voltage drop   resistance for .1 amp
         12                 0.1                 3.4                  3                        10.2                              1.8                                18

I have already tried this circuit. The leds didn't last long. From internet reading, the problem may be from the low resistance of the current limiting resistor and it's tolerance. I could use a higher resistance but that would result in a higher waste of power. These leds will eventually be solar powered.

- Scotty
195  Using Arduino / General Electronics / Voltage & current regulator on: October 01, 2012, 09:37:56 am
Am I correct in thinking that one of these could be used to regulate voltage and current to a string of series LEDs by adjusting the output voltage to the total recommended voltage drop across the string and adjustment of the recommended current through the LEDs and not be concerned about any current limiting resistor? - Scotty



+++Features+++
High-power LED constant current drive
Lithium battery charger (including ferroelectric)
4V, 6V, 12V, 14V, 24V battery charger
Nickel cadmium, nickel metal hydride battery pack charger
Solar panels and wind turbines
 
+++Specifications+++
Input Voltage: 5-35V
Output Voltage: Continuously adjustable from 1.25 V to 30V
Rated Output Current: 3A
Max. Output Current: 4A (more than 15W, preferably with a heat sink)
Size (L x W x H): Approx. 1.9 x 0.95 x 0.5 inch / 4.8 x 2.4 x 1.3cm
Indicator Light
Constant current indicator(red)
Charging indicator(red)
Charged full (green)
Battery use
l        Make sure of the voltage and current of the battery you need to charge
l        Adjust the constant voltage potentiometer to make the output voltage same to the charge voltage
l        Potentiometer Adjustment Direction: Clockwise (increase), counterclockwise (decrease)
Use the multimeter in 10A current scale to measure output short-circuit current, and adjust the current potentiometer to make sure the output current to the expected charging current value
l        The charge current of transfer lamp is default 0.1 times of the charging current (constant current value)
l        Connected to the battery and try to charging (for previous 5 steps, module input terminal is connected to power source, output load is NOT connected to batteries)
LED Constant Current Driver Use
l        Make sure operating current and Max operating Voltage of the LED you need to drive
l        Adjust the constant voltage potentiometer to make sure the output Voltage is up to LED Max operating Voltage
Use the multimeter in 10A current scale to measure output short-circuit current, and adjust the current potentiometer
l        to make sure the output current to the expected LED operating current
l        Join LED, test (For the above 3 steps, module input terminal is connected to power source, output load is NOT connected to LED)
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