hamoodyjamal

IR emitter = IR LED The reason TV remotes have great range is because the signal (form the remote) is sent in bursts (i.e. 10 bursts a second) meaning you can allow more current to pass through the LED --> strong signal. You see, LED's are rated i.e. 30mA max at continous current. If you look in the datasheet of most LED's you'll see that you can pass current greater than 30mA, say 70 or 80mA, if the current is in bursts. If you point a digital camera at the LED of a remote, and press any button, you'll see the IR LED flash and not continously ON. Which means greater current is passed at smaller intervals, thus more power = Greater range. Something that also helps, like audioguru mentioned, the remote sends modulated light (along with data) which can be detected easier by the IR receiver than just plain IR light. Even if you replace a remote's IR LED with another one, you'll most likely get the same range. ;D

Whats your project about? Maybe you mis spelt or calculated the values.

Wa'Alaikum Alsalam, Did you draw the schematic (circuit) yourself or did you get it from somewhere? From what im seeing, the arrangement doesn't look 100% correct. I see that you're using a PNP transistor, which means you need negative supply (or 0 as you'll read at the end) at the base. VB:Base voltage IB:Base current IE:Emitter current IC:Collector current VC: Collector voltage Beta: Gain : Amplification = hFE Alpha ??? sorry i dont know whats that either. One more thing, you dont say -5V, in this circuit. Its either 0 or Ground(GND) Correct me anyone if im wrong. Salam ;D

Hmm, your right!!! I guess I'll have to teach my physics teachers whos "teacher". Cheers mate ;)

Hey, I made a project similar to yours but the problem is that i got told of from my parants for using a laser beam. Old folks, what to do! So i switched to Infrared which is much more complicated (as you can see from the "Infrared Activated Switch" topic). It worked like a charm. But i hade to dismantle it and now im working on using infrared. Max distance i achived (testing phase) with the infrared would say is 5 meters. (good for home use). BTW, You better watch out when using a laser beam outside since there have been reports of lasers blinding the veiw of airplane piolets and those responsible have been arrested. I once achived 100m with my $1.5 (no bull, thats the average price in my country) laser. It too came with lenses that make shapes. After 1 day of using it, i dismantled it and took out the small PCB with all the stuff and it became like 3cm all together witht he lense. (but no battery). I have a habbit of opening things and taking a look. LOL, audioguru you wicked man! ;D

Cool Stuff Dude!!! BTW, can i use normal alaminium foil (kitchen foil)? ;D

That means your mains can supply a max of 32 x 220 = 7040W which is a lot smaller than what you need. Remember: Power Out (50,000W) = Power In 50,000 < 7040 (which is not true) --> you'll probably blow up your mains supply. Fuses cannot be arranged in a parallel setup. Im not really sure why but i know so. I think its because of the resistance difference. Both fuses dont have the EXACT resistance and thus one will blow up instantly becasue more voltage passes through it = higher current (i.e. 18A). Your best bet would be to get a fuse with rating higher than 32A, which i think is quite rare.

Hi audioguru, I found out the problem for the 555 timer overheating. I was looking at the datasheet (of the 555) and it said R1 and R2 should be between 1K and 1M. Before i was using, R1 and R2 which added up to 147 Ohm which is way too small. So i changed the components to still give 56KHz and the 555 timer stopped over heating. Great. BTW, i want to use an LM307 IC to power a Relay (instead of a transistor becasue a transistor is a SEMIconductor which will always trigger the 555 monostable since its very sensative to triggering) from the output of the receiver. I found a circuit on how to set it up. At first it worked. But then after re-setting it up (dont bother to ask why), it didn't work. I double checked for connection errors but everything is fine. Yet, it just doesn't want to work. I drew a picture of the schematic that i set up. Can you spot a problem? This may help you, im using the same supply to power both the LM307 and the IR receiver, while using a 12v and a 5v regulator for the LM307 and the IR recevier respectavly. Could there be conflict issues? Thanks! ;D

I agree, 50KW (50,000W) is alot of power. Remember "Power (W) = Current (I) x (times) Voltage (V)" In your case: P = 1 x 50,000 = 50,000W In addition, its way too high to be supplied from an ordinary home power supply. What do you need that much power for? BTW, safety doesn't play a role with such voltages. Dont you think? ;D

Hi all, After long period of searching, I couldn't find the spice model for the NE567 (by Philips, now obsolete yet I got it). Can anyone please direct me to where I can find it, or post the model for the NE567 Tone Decoder? I looked in the datasheet but no luck. I need it for Multisim 7. I tried looking for it, but I couldn’t find it. Maybe I’m not looking in the right path. Does anyone know if its there already in Multisim? Highly appreciated ;D

Hi audioguru, How can rectifying and filtering a transformer’s o/p increase its voltage? I don’t find it logical. By the way, I have a NE567 Tone-Decoder IC and am wondering on how to use it to replace those IR receivers that gave me such a headache. Can I use it to receive IR light, using a phototransistor as the input, oscillated at 56 KHz to drive a relay? Or just give a HIGH or LOW signal? I took a look at the datasheet and it showed me how to calculate the center frequency. That was Ok. But then I came across how to calculate the detection bandwidth and I was stuck on what it is? I thought it could be something similar to tolerance of the frequency? Am I right? Thanks! ;D

Hi audioguru, Problems after Problems!!!! Grrrrrrrrrrrrrrrrrrrrrrrrrrrrrr. During the testing procedures, I used a 9v battery to power the 555 timers. Everything was OK. Now, I used a 220V-12V transformer to power the 555 timers. Problem. The IC quickly overheats. I checked for wiring errors but all was fine. So I measured the current and it read 220mA which is darn a lot. I went back to using the 9v battery and everything was OK. Current with the 9v is around 35mA. I’m stuck on why the IC overheats when using the transformer (BTW, the transformer output is rectified and decoupled with an electrolytic capacitor of values 16v 1000uF). I asked my dad (who’s an electrical engineer) and said that the battery has internal resistance. I don’t know what he meant by that. What you say? Also, the TSOP1756 IR receiver turns out to actually be working. I thought it was busted, but it wasn't. I used it for testing, but now I really burnt it. Ahhhhhhhhhhhhhh. A problem with the TSOP1156 is that the output goes low for a split second when there is IR light. Where as the previous one (TSOP1756) kept low when there was IR light. How can I fix this dilemma? Thanks! ;D

Hi audiofuru, AGC? ??? ;D

Hi audioguru, That picture you attached which shows the effects for DATA. Im just sending plain IR light at 56KHz. See image attached. BTW, range isn't that important. Probably 1-4 meters is what i'll need. What you say? ;D

Hi audioguru, I haven’t been getting to build the project because of some problems. First, my soldering iron is kind of busted and I couldn't get one. Well, not yet. Secondly, my sister is here, from another city, so we're spending some quality time. BTW, I was testing the IR receiver module, and I accidentally burnt it. Not literally, but I applied 9V when the max is 6V. Opps! I went to get a replacement, and the only thing I was looking for was the number 56 on the module. When I came home, I noticed it was TSOP 1156. I used to have TSOP 1756. Will this be a problem? Hope not, because it looks like it functions the same. What you say? ;D

Aparantly Sasi didnt read the thread before posting. Quick recap Sasi, I've solved my problem in a much simpler way. Thanks anyway ;D PS: what do you mean by "Dont ask More Questions ....I am busy, but its working fine. ", when did i ask YOU anything?

Hi audioguru, I kind of tested your circuit. What i mean is that i didnt quite use the same components you specified. The reason is that i dont have them. i.e. i didnt add the voltage regulator, nor the capacitors, also i used SC945C trans. instead of BC107. Hopefully I'll go and buy them tomorrow and let you know how it comes along. Test result: no inversion! When there is IR light aimed at the receiver, the ouput at junctions CE are about 5V (HIGH), and when there is no light, output is 0V (LOW). I showed the schematic to my dad and he noticed there is a transistor connected to the GND and OUT of the IR receiver module which is set up like an inverter. So how i see it is your inverting something thats already inverted. What you say? Chow. Chow.

Hi audioguru, I'll Try and get the components for the circuit hopefully tomorrow and will let you know about the results. However, I did some testing, but with a different NPN transistor (SC945C) and the results where negative. I had a hunch that it was because of the 10K resistor, so I changed it to a much lower value of 100Ohm and the circuit worked like it was supposed to. I guess it was because I didn't use a BC107 transistor. What you say? Thanks again! ;D

hi audioguru, First of all, !!!!THANKS A MILLION!!!! :D I never really saw that 80K resistor. I guess thats a plus for us ;D Did you design that circuit your self? What Program? Chow. ;D

Hi audioguru, I forgot to mention that the input for the 1st transistor is 5V. If you go back and look through the thread, you'll see a picture of what I plan to do. And you can see that the receiver consists of a 56 KHz IR receiver module which is actually connected to a battery. When it receives IR, it will output 5V (which is the supply voltage) through its Vout junction. I cannot connect all that 5V through the BE. That’s why I need a current limiting resistor. The first transistor is connected as an inverter. And the second transistor is the replacement of the relay. I don’t know if this will affect your reply, but what the heck. BTW, I will be using the picture (attached) to build the monostable circuit. What do you think? I got it from: http://www.eleinmec.com/article.asp?4 As you can see, there is a 10K Ohm resistor near Pin2 and the Vs, is this what you're talking about? Also, one of the parts is a "0.01uF Metallised Polyester Film Capacitor", can I use a normal ceramic disc if I can’t find a Metallised Polyester Film Capacitor? Thanks. ;D PS: I will only be using 5V for everything. Although I have a 12V supply, I prefer lower voltage for IC's.

Hi audioguru, I'll do my best to get the TIP31. I was reading through the thread and came to your post where you mentioned "Why not use only a transistor to replace the relay?" And then I thought about it and said, "That’s a darn good idea!” I drew out a schematic for what I plan. The only problem I have is I don’t really know how to calculate the values ??? Of the resistors because their values relate and affect each other (I think). Would you be so kind as to find the values? The link for the datasheet of the transistor (BC107) is below: http://www.ortodoxism.ro/datasheets/stmicroelectronics/9293.pdf Schematic Explanation: The first transistor is used as an inverter to drive the second transistor which in turn will trigger the 555 monostable circuit depending on the input of the first transistor. Thank you very much. ;D

Hi audioguru, I'll see if i can find the TIP31 in some stores. However, if i cant get my hands on it, can you tell me if this will be equivilent? http://www.alldatasheet.co.kr/datasheet-pdf/view/STMICROELECTRONICS/BFY51.html Oh yeh, what are the charastaristics of a General Purpose Transistor? I once read on a website that the Hfe should be around 100. What you say? ;D

Hi audioguru, I'll add those capacitors you told me about. BTW, I was reading about the 555 timer set as a monostable circuit and I came across this line "For a simple 555 monostable, the trigger pulse must be shorter than the output pulse" found at http://www.doctronics.co.uk/555.htm#triggering Can you please explain this to me? And what are the affects if the beam is blocked for more than 10s? Also, I live in the United Arab Emirates. There are Maplin and radioshack stores near where i live. So which transistors do you recommend i use for conducting 1A? I dont know if this helps, but the alarm circuit draws arround 850mA which is quite close to the limits of a 1A transistor? any tips on how to avoid damage to anything? Thanks ;D

Question: why dont i just use one capacitor i.e. 220uF? Also, since I will be using two 555 timers, do i need to double the values? Regarding the transistors, i understand the TIP31 is the better choice. But if i cant find it, are there any equivilents? ;D

Hi audioguru, The time-out thing is no problem. I want the alarm to sound for 10s + the time the beam is blocked. So that’s ok. What are current-spikes that are caused by the 555 timer? And how are they dangerous to the other components? And what do you mean by "well-filtered", do I need to add some extra components? BTW, do you know a code for a General Purpose transistor that can pass 1A through CE? I already have some in mind (2N2222A, TIP31); I just want a second opinion. Thanks. ;D