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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: Re: Hmevision ir transmitter
No worries Frank Not often you get too much advice!! Back to the baby Ian B >-----Original Message----- >From: Frank Mc Alinden [mailto:armagh@xxxxxxx] >Sent: 01 June 2002 10:56 >To: ukha_d@xxxxxxx >Subject: Re: [ukha_d] Re: Hmevision ir transmitter > > >Hi Ian + Ian > I think i confused myself more than Andy . Anyway its >probably better if only one person advises Andy . I will keep dabbling with >my idea for transmitting until i get the bloody thing to work. > >Frank Mc > ----- Original Message ----- >From: "Ian B" <Ian@xxxxxxx> >To: <ukha_d@xxxxxxx> >Sent: Saturday, June 01, 2002 7:15 PM >Subject: RE: [ukha_d] Re: Hmevision ir transmitter > > >> Good catch on the design. It was late last night after a fun >time with the >> new baby. >> >> I agree about the recent post of messages being confusing to say the >least. >> Your design is better than mine and I have set it up as a pdf for >simplicity >> and recording at my end. I am still learning after all. >> >> Both of the designs achieve the same aim of zoned output >controlled by one >> of HV ports. I thought some of the previous discussion was going >off track >a >> bit and all that negative logic was horrid. >> >> As soon as I find out the path on the web server to my web site I will >post >> the pdf's there but in the mean time here is another apology and another >4k >> attachment. All down to playing primary domain controller removal and it >> deleted my accounts as well - dohh. >> >> Andy - sorry if all this is confusing and shout if anything (apart from >> everything, oh well, that as well) is unclear. >> >> A quick lesson on transistors!! >> These other transistors we are talking about with the arrow >going into the >> base rather that out of it operate in a different way. You can think of >the >> ones where the arrow goes out of the base BC182 etc. as having >the turning >> on power flow into the base and out of the emitter. The other ones like a >> BC327 etc. have the turning on power flow into the collector and OUT of >the >> base. This is very simplistic and of course current is negligible when >> referring to the base. In both types the main flow of current when the >> device is active is from collector to base. Hopefully this makes sense >(and >> I am correct). >> >> Ian B >> >> >-----Original Message----- >> >From: Ian Davidson [mailto:ian@xxxxxxx] >> >Sent: 01 June 2002 09:32 >> >To: ukha_d@xxxxxxx >> >Subject: Re: [ukha_d] Re: Hmevision ir transmitter >> > >> > >> >Hi Ian B >> > >> >If you wish to do it the way you suggest an easier circuit would be >> > >> >http://galeforce9.dnsalias.org/dsc0_0069.jpg >> > >> >A few less components and current draw off the ports of HV still >> >well within >> >the limits. >> > >> >As I've said I don't have HV (maybe one day!) but if the members that do >> >have it and require the IR say which port they would prefer to use and >the >> >maximum ratings they would want to control then I'm sure we could design >a >> >circuit with minimum components that most people even with minimum >> >electronics experience could build. >> > >> >At the moment things keep changing so I think any designs should be >shelved >> >until a common goal is reached as to what is required, if not the poor >> >people trying to understand basic electronics from that last batch of >> >messages will be frightened off for life !!! >> > >> >Ian D >> > >> >----- Original Message ----- >> >From: "Ian B" <Ian@xxxxxxx> >> >To: <ukha_d@xxxxxxx> >> >Sent: Saturday, June 01, 2002 12:46 AM >> >Subject: RE: [ukha_d] Re: Hmevision ir transmitter >> > >> > >> >> Your circuit looks like I had in mind back in year dot. I >have sat down >> >and >> >> had a think about this and we have been leading you up the garden path >a >> >> bit. Fun trip though wasn't it. Anyway, here are my thoughts.......... >> >> >> >> I have attached (for my sins) a very small pdf with the circuit (not >> >quite) >> >> as I saw it in my minds eye. Things have changed a bit and the TR1 >codes >> >> etc. no longer refer to the same transistors so pay attention. After >some >> >> (considerable) thought I figure the best way to do this is use Port C >in >> >> OUTPUT mode. According to the specs it can drive TTL and CMOS. This >means >> >> LED's so enough current for us. >> >> >> >> In off state PortC must be all zeros and we don't care what the IR out >is >> >> doing. In this state TR2 is not conducting so the LED's are never on. >> >> >> >> Right, from the left ($^%!) we have a pull up resistor connecting to a >> >> tranny TR1. When HV transmits IR the base is pulled low and the tranny >> >stops >> >> conducting. I assume here that HV switches the ground. This in turn >sends >> >> the voltage through TR2 high. This is where the clever zoning bit is. >If >> >> PortC pin x is high it drives the tranny TR2 base and the voltage >reaches >> >> TR3 - zone ON. If however the PortC pin x was low the voltage would >never >> >> reach TR3 and nothing happens. As soon as the voltage reaches TR3 it >> >> conducts and the LED's come on! Voila...... Obviously the LED's on the >> >right >> >> would be as many as you want i.e. 8 in your case. >> >> >> >> Well, that's the theory anyway. >> >> >> >> There may be a better way round this but it is late and I am tired >> >(excuses >> >> excuses). >> >> >> >> I hope this is helpful and that I have got it somewhere near correct. >> >> >> >> Off for a midnight snack, have fun. Let me know if the >diagram and text >> >are >> >> rubbish. >> >> >> >> Ian B >> >> >> >> p.s. you owe me one for making me think!! ;-)) >> >> >> >> >-----Original Message----- >> >> >From: andy_powell_is [mailto:ukha@xxxxxxx] >> >> >Sent: 31 May 2002 20:25 >> >> >To: ukha_d@xxxxxxx >> >> >Subject: [ukha_d] Re: Hmevision ir transmitter >> >> > >> >> > >> >> > >> >> >Ok, I'll try again.... (this is an abridged version!) >> >> > >> >> >I've got the original circuit working.. it was the 2N2222 that was.. >> >> >err dead.. replaced it and it's all ok now... >> >> > >> >> >The circuit now consists of the diagram at >> >> >http://www.automated.it/homevision/HVIR2.jpg but with the bit that >> >> >says Homevision port removed... >> >> > >> >> > >> >> >> I think I've read the relevant messages. IF I've read them right >> >> > >> >> >There was a sudden rush of them, mainly due to my lack of >> >> >intelligence :P >> >> > >> >> >> port a o/p is via a PNP which means it will source the o/p and give >> >> >a +volts >> >> >> supply. >> >> > >> >> >I've used the phrase before, and I'm going to use it again, err, >> >> >chicken soup... >> >> > >> >> >> This lunch I built up a simple circuit details are here: >> >> >> http://galeforce9.dnsalias.org/dsc0_0064.jpg >> >> > >> >> >Thanks, I've saved them for reference... >> >> > >> >> >> You only need the one transistor. It is ZTX651 I had on the bench >> >> >at work. >> >> > >> >> >Awwww, I have a big bag of 2N2222's and BC182's :( >> >> > >> >> > >> >> >> It will handling up to 2A and does not require any form of >> >> >heatsink. It is >> >> > >> >> >I've put a 1k resistor in from the power supply to the collector of >> >> >the first transistor and according to the Circuit maker I'm pulling >> >> >2.995ma (the 1k resistor appears to drop the current from 32.5ma to >> >> >2.995ma, apparently)... is that a problem? am I going to upset >> >> >homevision by putting that resistor in there? it still works on the >> >> >breadboard... >> >> > >> >> >Bearing in mind that this is only 1/8 of the circuit, if I add 7 more >> >> >am I going to pull too much current? >> >> > >> >> >> an e-line transistor and has a very low on resistance. It will only >> >> >take >> >> >> about 1mA of current to drive it from homevision. If the led's you >> >> >use are >> >> >> 20mA devices then each transistor will drive 100 of them. If this >> >> >is OTT >> >> > >> >> >Phoaaaarrrrr!! 8 zones of 100 emitters :P >> >> > >> >> >> The circuit is wired just to show it working ie the 10K resistor to >> >> >the base >> >> >> is connected to the 5V rail to simulate a 5v o/p from HV. >> >> > >> >> >So the HV port A supplies +5v too?? This is the bit I'm really unsure >> >> >of... should I connect the base of the first emitter to Homevisions A >> >> >ports via a 10k resistor (one for each A port ie one for A1, one for >> >> >A2..etc)? >> >> > >> >> > >> >> >> If you drop me your address Andy I'll stick it in the post and you >> >> >can >> >> >> experiment with it. (It is no good to me !) >> >> > >> >> >I'll email it privately... :D >> >> > >> >> > >> >> >> >> >> >> In answer to an earlier question you are correct that for current >> >> >to flow it >> >> >> needs to complete a circuit. When voltage is applied to the base of >> >> >a >> >> >> transistor it flows through the base emitter junction of the >> >> >transistor to >> >> >> ground. >> >> > >> >> >You've lost me with this. Where is this? is it that it flows (in the >> >> >circuit at the url above) to the second transistor via it's emitter >> >> >and off to the seond and then to the emitter of that and hence to >> >> >ground? >> >> > >> >> > >> >> >> I hope I've explained things ok, I'm not the best teacher, but if >> >> >you are >> >> >> unsure just ask. >> >> > >> >> >You're doing pretty well if you ask me... >> >> > >> >> >> Again so as not to offend the list if ANYONE wants this topic off >> >> >list just >> >> >> say and it will be. >> >> > >> >> >I did ask and the suggestion was that quite a few people are >> >> >interested, not only that but that this was one of the few on topic >> >> >threads... :O >> >> > >> >> >Thanks for all your help >> >> > >> >> > >> >> >Andy >> >> > >> >> > >> >> > >> >> >For more information: http://www.automatedhome.co.uk >> >> >Post message: ukha_d@xxxxxxx >> >> >Subscribe: ukha_d-subscribe@xxxxxxx >> >> >Unsubscribe: ukha_d-unsubscribe@xxxxxxx >> >> >List owner: ukha_d-owner@xxxxxxx >> >> > >> >> >Your use of Yahoo! Groups is subject to >> http://docs.yahoo.com/info/terms/ >> > > >> > > >> > > >> > >> > >> > For more information: http://www.automatedhome.co.uk >> > Post message: ukha_d@xxxxxxx >> > Subscribe: ukha_d-subscribe@xxxxxxx >> > Unsubscribe: ukha_d-unsubscribe@xxxxxxx >> > List owner: ukha_d-owner@xxxxxxx >> > >> > Your use of Yahoo! Groups is subject to >http://docs.yahoo.com/info/terms/ >> > >> > >> >> >> >> >> For more information: http://www.automatedhome.co.uk >> Post message: ukha_d@xxxxxxx >> Subscribe: ukha_d-subscribe@xxxxxxx >> Unsubscribe: ukha_d-unsubscribe@xxxxxxx >> List owner: ukha_d-owner@xxxxxxx >> >> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ >> >> >> >> >> For more information: http://www.automatedhome.co.uk >> Post message: ukha_d@xxxxxxx >> Subscribe: ukha_d-subscribe@xxxxxxx >> Unsubscribe: ukha_d-unsubscribe@xxxxxxx >> List owner: ukha_d-owner@xxxxxxx >> >> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ >> >> > > > >For more information: http://www.automatedhome.co.uk >Post message: ukha_d@xxxxxxx >Subscribe: ukha_d-subscribe@xxxxxxx >Unsubscribe: ukha_d-unsubscribe@xxxxxxx >List owner: ukha_d-owner@xxxxxxx > >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ > > >
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