Hobbies Electronics Enthusiasts Club, All elect/robotics lovers! pls come!
|
|
 Aug 1 2007, 10:56 PM
|
 
Junior Member
26 posts Joined: Sep 2006  
|
guys....
i need help with my project. doing some electronic locator thingy. something like a wireless doorbell but more like a key locator o sometin like tat. to locate some misplace items. can anyone help me where to find info abt tis project? o mb u guys can share wit me some idea? |
|
|
|
|
|
Aug 1 2007, 11:00 PM
|
Senior Member
657 posts Joined: Jan 2003 From: Serdang, Bentong(Pahang)
|
locator?
 put RFID tags on all items...hehehe then when u misplaced any of them, use a scanner to locate it ...but not for long range tho. |
|
|
Aug 2 2007, 12:35 AM
|
|
Junior Member
26 posts Joined: Sep 2006
|
i tot o using RFID. but RFID needs a reader rite?
plus RFID usually needs a pc to decode the thing rite? i just wan to use a normal RF la....i tot o using say...5 frequency to lacate 5 items. but i need help in designing the transmitter reciever. can help me where i can find info on tis? o if u haf a circuit design on it d...can share wit me? hehe |
|
|
Aug 3 2007, 01:21 PM
|
|
Junior Member
205 posts Joined: Dec 2006
|
Why use RFID as key locater while u can use it as a key.
How about RFID door opener? You need a simple microcontroller,Rfid reader and card, selenoid and a little bit programming. Everyone of your family members can have different ID onthe RFID card to open the door. Cost about RM500. |
|
|
Aug 7 2007, 02:07 AM
|
Senior Member
912 posts Joined: Jan 2003 From: Kuala Lumpur/Bangi
|
i'm planning to build robot for my FYP...th ename of my robot is intelligent autonomous rover robot...the robot can elak obstacle when doing exploration..rite now still doing the design..dunno what design should i use...anyone can give opinion bout my project...
|
|
|
Aug 7 2007, 01:54 PM
|
Junior Member
7 posts Joined: May 2007 From: de'caves of rock!
|
i just wonder is it possible for a laymen like me who doesn't even have the basic knowledge on circuits (i can say i even fail the theory questions in kemahiran hidup tingkatan 3) to move into this hobby?
is it hard to learn about eletronic stuffs (as hobby)? before i even drown myself in pools of information, can somebody kind enuf to throw in some links to tutorials/ fundamental info on this hobby that is comprehensive even to newcomers? This post has been edited by erh_teo: Aug 7 2007, 01:56 PM |
|
|
|
|
|
Aug 9 2007, 11:57 PM
|
All Stars
10,596 posts Joined: Jan 2003 From: Hinamizawa
|
why the higher input impedance is better in amplifer?
|
|
|
Aug 10 2007, 01:14 AM
|
Senior Member
2,376 posts Joined: Dec 2005
|
QUOTE(jasonkwk @ Aug 9 2007, 11:57 PM) why the higher input impedance is better in amplifer? so that the all signal voltage will drop in the input of the amplifier. therefore no voltage is lost elsewhere. |
|
|
Aug 16 2007, 12:43 PM
|
|
All Stars
10,596 posts Joined: Jan 2003 From: Hinamizawa
|
QUOTE(ryansxs @ Aug 10 2007, 01:14 AM) so that the all signal voltage will drop in the input of the amplifier. therefore no voltage is lost elsewhere. noob questionswhen I look at the internal component of an omamp, I saw that the input and output are not connected, why is it so?how are you going to amplify the signal?  This post has been edited by jasonkwk: Aug 16 2007, 12:43 PM |
|
|
Aug 17 2007, 12:36 AM
|
|
Senior Member
2,376 posts Joined: Dec 2005
|
QUOTE(jasonkwk @ Aug 16 2007, 12:43 PM) noob questions Good question.when I look at the internal component of an omamp, I saw that the input and output are not connected, why is it so?how are you going to amplify the signal? Well the diagram that you are referring is just the model representation of an op-amp circuit. That is not the real internal circuit of an op amp. You may look at the link here, to see the internal circuit http://en.wikipedia.org/wiki/Image:OpAmpTr...red_Labeled.svg To make our calculations easier, we tend to use the model of op-amp circuit. |
|
|
Aug 18 2007, 08:40 PM
|
|
All Stars
10,596 posts Joined: Jan 2003 From: Hinamizawa
|
 how to prove Ib3=Ie3/1 +beta? This post has been edited by jasonkwk: Aug 18 2007, 10:37 PM |
|
|
Aug 20 2007, 01:11 PM
|
|
Senior Member
2,376 posts Joined: Dec 2005
|
QUOTE(jasonkwk @ Aug 18 2007, 08:40 PM) how to prove Ib3=Ie3/1 +beta? |
|
|
Sep 10 2007, 07:23 PM
|
Senior Member
606 posts Joined: Feb 2006 From: St James' Park
|
Hi...currently im doing IR transmitter and receiver circuit,well basically..transmitter had oredi done,jus tat my receiver got a bit problem,whenver my receiver detect IR signal from my transmitter,it only detected for 1 or 2 seconds,wonder wut going wrong??izzit frequency not correct??i use modulated receiver..which the output shud be either 1 or 0,i had changed several receiver but still get the same result..help pls!!
|
|
|
|
|
|
Sep 11 2007, 10:22 PM
|
Junior Member
427 posts Joined: Jun 2005
|
whats ur application ? r u sure u got the right pair of transmitter and receiver as there are different of wavelength for IR
|
|
|
Sep 11 2007, 10:55 PM
|
|
Senior Member
606 posts Joined: Feb 2006 From: St James' Park
|
QUOTE(sooyewguan @ Sep 11 2007, 10:22 PM) whats ur application ? r u sure u got the right pair of transmitter and receiver as there are different of wavelength for IR yaya...tats confusing me actually..cos most of the shop don provide datasheet for the IR transmitter and receiver..can u shwo some list??basically im building a robot to avoid obstacles..then if the IR signal detected any object in front,it will reflect back to my receiver...i need a proper datasheet of the transmitter and receiver as i don kno much bout it...and those shop selling in jalan pasar don provide them  |
|
|
Sep 14 2007, 09:35 AM
|
|
Senior Member
2,376 posts Joined: Dec 2005
|
QUOTE(Calcool77 @ Sep 11 2007, 10:55 PM) yaya...tats confusing me actually..cos most of the shop don provide datasheet for the IR transmitter and receiver..can u shwo some list??basically im building a robot to avoid obstacles..then if the IR signal detected any object in front,it will reflect back to my receiver... Normal shop does not provide you datasheets, you have to search for it.i need a proper datasheet of the transmitter and receiver as i don kno much bout it...and those shop selling in jalan pasar don provide them Just google for it or register to www.farnell.com or www.rscomponents.com, and try searching in their database for datasheets. |
|
|
Sep 15 2007, 02:13 AM
|
|
Senior Member
606 posts Joined: Feb 2006 From: St James' Park
|
QUOTE(ryansxs @ Sep 14 2007, 09:35 AM) Normal shop does not provide you datasheets, you have to search for it. Alright..thxs for the info,ill try to search the correct sensor for my projectJust google for it or register to www.farnell.com or www.rscomponents.com, and try searching in their database for datasheets. |
|
|
Sep 15 2007, 10:27 AM
|
|
Junior Member
427 posts Joined: Jun 2005
|
if money is not a problem, just buy the sharp IR module and all your problem will be solved, good luck.
|
|
|
Sep 19 2007, 04:36 PM
|
|
Junior Member
8 posts Joined: Apr 2007
|
Anybody know where I can source for these potentiometers:
- 25k log (25k A) - 250k linear (250k B) - 100k reverse log (100k C) I went to Jalan Pasar already but still couldn't find the 25k A and 100k C. They only have 250k B. Where can I get this Triple pole Double throw (3pdt) footswitch? Need this for true bypass switching purpose  Got 9 pins!!! Added on September 19, 2007, 5:26 pm QUOTE(empire23 @ Jun 26 2007, 02:30 AM) For capacitors in the signal path, i'll stick with metallized film polyprolene or polyphenyl sulphate caps, although i will go to Polyester and if forced to, then ultra high quality electrolytics. If possible, and if i can keep the offset low enough by properly tuning the power supply, i won't even use caps at all. But then again, they're like condoms, they give you that extra safety net if shit happens, but it's always not as good as just sticking it without one. Do you know which shop in Jalan Pasar got sell flim type of capasitor? Asked most of the shops there already and they only have electrolytic type.For filters, i prefer Silver Mica, i also like it for ground decoupling due to it's somewhat better characteristics in the stability domain. I also use Ceramics when decoupling ground to V+, i use values depending on the frequency of the noise i want to hammer out, but i like .1 uF as my standard. For the power supply, i use Electrolytics as the main filter and capacitance tanks. For bypassing and snubberizing, i use high voltage self healing films since they work well with high frequency pulses and can help stop EMI and RFI from penetrating the design. And last if not least, tantalums for regulator stability. I want to use the flim type capasitors for my signal path. What is the best capasitor type for signal path? This post has been edited by spx: Sep 19 2007, 05:46 PM |
|
|
Oct 2 2007, 03:17 PM
|
Senior Member
627 posts Joined: Aug 2006 From: ~sHaH-aLaM, puCh0nG & g0m84k~
|
i have a project to be run in 2 days...
can you guys suggest a link or an interesting project that uses easily obtained electronic iinstruments?? help me,. quite urgent.. thx in advance.. |
| Change to: |  0.0245sec
 0.61
 6 queries
 GZIP Disabled
Time is now: 28th November 2025 - 04:41 PM |
Quote