Post by thread:[PIC]: HELP REQUIRED FROM NEWBIE

Hi Guys, Could someone pls let me know where can I get information on, PIC (preferably 16877 because I purchased a 16877 Development board from Futurlec.com) Controlled AC relays using a light sensor as an input ? I have searched thru the internet but can seems to find one that is close to what I want. Most of them are related to garden or drive-way lights which will turn on during the night. My objective is, if the light is on, the PIC will switch on 2 of the 4 relays for say 8 seconds while the other 2 relays are in off-position. After 8 seconds, alternate the 2 pairs of relays on/ off position. When the light is off, reduce the on/ off delays from 8 seconds to 4 seconds. I know there will not be an exact project available in the internet but if I can find one that is close, I hope I can make changes to the source code to suit my needs (part of learning). Thanks a zillion. cheers, --------------------------------- Do you Yahoo!? Yahoo! Mail - Easier than ever with enhanced search. Learn more.

Andrew Rich wrote: > Here is the flow > > 1. Get the datasheet > 2. Download MPLAB 7.0 > 3. Use MPLAB to simulate, syntax check and create the HEX file used for > programming > 4. I use a PIC programmer that hangs of the serial port > 5. Surf the web for little examples i started out turning lights on and > off > > What specifically do you need to know ? > > Ask lost of questions I'm not sure what your question really is, but I noticed that debugging in the circuit was not in your 5 step program. It's a good idea use the simulator before trying your code on real hardware, but there is still no substitute for testing and debugging the real thing. For most hobbyists, that means using a ICD2. ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com

Hi Andrew, Sorry for not being clear. I am working on a project using a PIC (16F877 or 16F628 ) or even AVR (90S2313, 90S8515) to control 4 relays (2 pairs); on and off for say, 8 seconds interval for 24/7. Powerheads (fish tank type) operating at 220v will be attached to the relays. During the day, when the fish tank lights are on, I want the on/ off interval to be 8 seconds. During the night when the lights are off, I want the on/ off interval to be 4 seconds. Thus, I think of using a light sensor as an input logic so as to use different interval routines within the PIC. As I am totally new to MCU and electronics hence, if I can get hold of a project that is as close to my requirement as possible, that will greatly help. The only plus I have is, I have some BASIC programming background. Hopefully, I can pick up quickly on modifying the source code to suit my needs. Thanks in advance for the help. cheers, Andrew Rich <spam_OUTvk4tecTakeThisOuTtech-software.net> wrote: Here is the flow 1. Get the datasheet 2. Download MPLAB 7.0 3. Use MPLAB to simulate, syntax check and create the HEX file used for programming 4. I use a PIC programmer that hangs of the serial port 5. Surf the web for little examples i started out turning lights on and off What specifically do you need to know ? Ask lost of questions

Interesting, The thing that imediatly jumps out at me is the cyclic rate of the relays. At a 8 second cycle rate, that works out to be ~10,000 cycles a day - more at four seconds. I wouldn't expect a mechanical relay to have a very long lifespan at that rate. If you actualy need this switching rate I'd reccomend you look into some other options. Solid state relays are an option, or you could control it with triacs. A pic is a good match for this type of application. I would generaly reccomend the 16F877 / or 16F876 for a beginner to learn with. But something of this size could be done with a much smaller part (16F629 probably) Most of the people on this list program with assembly. Since you mention you have some BASIC experiance maybe you should look into ME labs PicBasic Pro. http://www.melabs.com They even have a demo version that's probably enough to do what you're asking. There's also some good PBP specific resources out there like this one: http://www.picbasic.co.uk/forum/ The basic program would actualy be quite simple, it'll probably look something like this: lightsensor var portb.0 relay var portb.1 on con 1 'these depend on how you wire your relays off con 0 day con 1 'depends on sensor type and how you wire it input lightsensor output relay Main: if (lightsensor = day) then relay = on pause 8000 'number of milliseconds to pause relay = off pause 8000 else relay = on pause 4000 relay = off pause 4000 endif goto main This is just a quick hack, and I imagine you will want to add features and such, but it should give you some ideas. -Denny > > Sorry for not being clear. I am working on a project using a PIC (16F877 or 16F628 ) or even AVR (90S2313, 90S8515) to control 4 relays (2 pairs); on and off for say, 8 seconds interval for 24/7. Powerheads (fish tank type) operating at 220v will be attached to the relays. During the day, when the fish tank lights are on, I want the on/ off interval to be 8 seconds. During the night when the lights are off, I want the on/ off interval to be 4 seconds. Thus, I think of using a light sensor as an input logic so as to use different interval routines within the PIC. > > As I am totally new to MCU and electronics hence, if I can get hold of a project that is as close to my requirement as possible, that will greatly help. The only plus I have is, I have some BASIC programming background. Hopefully, I can pick up quickly on modifying the source code to suit my needs. > > Thanks in advance for the help. > > cheers, > >

techy fellow wrote: >Hi Andrew, > >Sorry for not being clear. I am working on a project using a PIC (16F877 or 16F628 ) or even AVR (90S2313, 90S8515) to control 4 relays (2 pairs); on and off for say, 8 seconds interval for 24/7. Powerheads (fish tank type) operating at 220v will be attached to the relays. During the day, when the fish tank lights are on, I want the on/ off interval to be 8 seconds. During the night when the lights are off, I want the on/ off interval to be 4 seconds. Thus, I think of using a light sensor as an input logic so as to use different interval routines within the PIC. > > A mechanical relay will wear out quickly at 8S on/off. I'd use an opto-SCR within a diode bridge to drive the load. Or, the sharp#PR31HD22NSZ. It can handle 1A at 220VAC, a functional replacement for mechanical relays. You must be VERY careful of your PCB layout, to prevent AC from getting into your controller on a moist day; to solve this, you will need to coat the PCB with a plastic spray. I'd use an PIC12F629 to drive all 4 Opto-relays, then use the MCLR\ input as a light sensor input. If you use the sharp optos, their input current load is very low, less than 5Ma (but in practice, 2Ma always worked) so if you stagger the outputs (2 ON, 2 OFF at the same time) you can actually make a transformerless power supply from 220VAC to control it. You can count 50/60 Cycle power to have a very accurate time base. If you use tantalum caps and pot the whole thing, it'll still be working at the next millenium. BASIC sounds good, but you might find that JAL is even easier for this project; JAL is a form of PASCAL. --Bob {Quote hidden}> >As I am totally new to MCU and electronics hence, if I can get hold of a project that is as close to my requirement as possible, that will greatly help. The only plus I have is, I have some BASIC programming background. Hopefully, I can pick up quickly on modifying the source code to suit my needs. > > > >Thanks in advance for the help. > >cheers, > > >Andrew Rich <.....vk4tecKILLspam@spam@tech-software.net> wrote: >Here is the flow > >1. Get the datasheet >2. Download MPLAB 7.0 >3. Use MPLAB to simulate, syntax check and create the HEX file used for >programming >4. I use a PIC programmer that hangs of the serial port >5. Surf the web for little examples i started out turning lights on and off > >What specifically do you need to know ? > >Ask lost of questions > > > > -- Note: Attachments must be sent to attachKILLspamengineer.cotse.net, and MAY delay replies to this message. 520-219-2363

piclist-bounces@mit.edu wrote: > Interesting, > The thing that imediatly jumps out at me is the cyclic rate of the > relays. At a 8 second cycle rate, that works out to be ~10,000 cycles > a day - more at four seconds. I wouldn't expect a mechanical relay to > have a very long lifespan at that rate. Yes, the relay life could be an issue. A long time ago, i constructed a powerhead controller for my reef tank using optically coupled triacs. The circuit didn't have a PIC; I used a CMOS counter to count AC line cycles through an H11AA. There are a lot of examples on the web on using optically coupled triacs. For night/day sensing, wasn't there a piclister who did just such a project? In any case, you can use MPLAB and MPSIM to learn about PICs and assembly without having to have a working circuit. And the 'blinking LED' project still has lasting value if you have limited experience with building actual hardware. The piclist site has a lot of useful info and tutorials. Microchip has some code templates.

Hi, If you want to test your program in JAL language, you can take a look at Jalss ( http://pic.flappie.nl/ ) which is the graphical simulator for JAL language. If you are interrested by Melabs PBP basic, assembler or Jal, there is Microdev ( http://sourceforge.net/projects/microdev/ ). This is although a graphical and real time simulator. They can help you to start without a real board. Moreover they are both free. Regards, Nicolas > In any case, you can use MPLAB and MPSIM to learn about PICs and > assembly without having to have a working circuit. And the 'blinking LED' > project still has lasting value if you have limited experience with > building actual hardware. The piclist site has a lot of useful info and > tutorials. Microchip has some code templates. >

Hi. First, do not use upper case only in the subject. Many regards that as "shouting" and you will get fewer replies. Second, I think that a subject that better says what it's all about would have been better. No one is in the position to "require" anything from the list, and doing that will probably just give you fewer replies anyway... With that said, > There are a lot of examples on the > web on using optically coupled triacs. Maybe something like thse modules : cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3865095804 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3865085593 Much easier to use then discrete components and you get stuff like zero crossing detection builtin. Best Regards, Jan-Erik.

> Second, I think that a subject that better says what it's > all about would have been better. I agree. But - > No one is in the position > to "require" anything from the list, and doing that will probably > just give you fewer replies anyway... There *seems* to be a misunderstanding of the meaning of a word here. "Require", in this context, is essentially interchangeable by (the vast majority of) people who use English as a first language, with words such as 'wanted', 'requested', 'desired' etc. For such people the word does not convey any sense of 'demand', 'insist' etc in this context. The opposite confusion can also occur. On a prior occasion a poster used the word "demand". This was taken by someone (person O) to mean "insist" and a significant fire-fight occurred when person O demanded that nobody demand things of them. The poster was French :-) - to them the word "demand" was a clear english version of 'demande' = ask. Russell McMahon

> > No one is in the position > > to "require" anything from the list, and doing that will probably > > just give you fewer replies anyway... > > There *seems* to be a misunderstanding of the meaning of a word here. > > "Require", in this context, is essentially interchangeable by (the > vast majority of) people who use English as a first language, with > words such as 'wanted', 'requested', 'desired' etc. For such people > the word does not convey any sense of 'demand', 'insist' etc in this > context. HI. Point taken, Sorry. > The poster was French :-) - to them > the word "demand" was a clear english version of 'demande' = ask. He he :-) It's like when George W Bush said that : "The French can't do anything, they don't even have a *word* for "entrepreneur" !!" :-) Regards, Jan-Erik.

> He he :-) > It's like when George W Bush said that : > > "The French can't do anything, they don't even have > a *word* for "entrepreneur" !!" That's a big word for Dubya. You do know that "entrepreneur" is (or was originally) a French word ? But back to the thread - Most people here have been around on this list for a while, know how it works, and interactions are generally pretty good. For those that are new or feel a little awkward or unsure about posting, here's a crash course in what you can do for yourself (and etiquette, another French word) "How to ask questions the smart way" http://www.catb.org/~esr/faqs/smart-questions.html Many problems can be solved simply by the process of putting a query together for others to read. When you have to explain something to others it makes you think a little deeper

At 10:39 AM 1/6/2005 +1300, you wrote: > > He he :-) > > It's like when George W Bush said that : > > > > "The French can't do anything, they don't even have > > a *word* for "entrepreneur" !!" > >That's a big word for Dubya. You do know that "entrepreneur" >is (or was originally) a French word ? To be fair to the shrub, "entrepreneur" does not mean the same in French as in English (it apparently means more like the English word "contractor"). Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" .....speffKILLspam.....interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

If possible, a schematic (PCB layout won't hurt either) and code will be nice. The reason why I didn't asked for the above in the first place was because I worried some might think that I want to be 'spoon-fed'. As I mentioned, I am a newbie (that's why I didn't ask appropriately in the first place -- no pun intended). I have completed some electronic projects before by following electronic projects published in magazines and internet links. Basic knowledge such as, identifying basic electronic components, etching PCB, soldering components to PCB and 'blowing' codes into MCU, I can handle it. Beyond this (designing of circuits and coding from scratch), I can't. I do have the following hardware related to MCUs. Bought them enthusiastically but, no time to really sit down to learn how to use them effectively. - PICStart Plus board, - ICD2 - Kit 128 for PICs (from Kitsrus) - 100% self-built a PIC development board appeared in one of EPE magazine. Working condition. - STK500 - STK501 - AVR ICE 200 - Kit 123 for 8051 family (from kitsrus) Comtemplating to buy a BASIC programming software for either PIC (eg. PicBasic Pro) or AVR (Bascom AVR) since I know BASIC. Almost zero knowledge on Assembly and 'C'. As one can see, I can't even decide which MCU is suitable for newbie. I am the type that prefer to learn along the way (by completing projects), which may not be a good way to learn electronics. But, this is how I learned to play the guitar (learn new chords from new songs). cheers, Andrew Rich <EraseMEvk4tecspam_OUTTakeThisOuTtech-software.net> wrote: You have some options. You really want a to know whether it is day or night right ? And then turn on / off some switches. You can use the comparators in the 16F628 or 16F877A The 16F877A has the advantage of A/D I understand what you are doing, do you need code ? do you have a programmer ? Do you have MPLAB ? Have you programmed 16F628 / 16F877A before ? {Original Message removed}

> Comtemplating to buy a BASIC programming software .... AVR (Bascom > AVR) since I know BASIC. A 100% functional except for some debug aspects, 100% free version of BASCOM is available for up to 2k of output code. It will program through eg your STK500. It is a stunningly simple way to get going in programming. You can have a LED (or 8) flashing in minutes once you get things hooked up. An exceptionally fast easy and cheap way to start. BASCOM allows mixed assembler and BASIC statements if desired, giving the ultimate in power flexibility and confusion :-). Try it, you'll love it. Stunning range of inbuilt functions / subprograms allow you to interface to many standard peripherals with a minimum of code (or understanding). LCD, PC keyboard, 1 wire devices, I^2C, flash cards, and more. RM

----- Original Message ----- From: "Jinx" <joecolquittspam_OUTclear.net.nz> To: "Microcontroller discussion list - Public." <@spam@piclistKILLspammit.edu> Sent: Wednesday, January 05, 2005 4:39 PM Subject: Re: [PIC]: HELP REQUIRED FROM NEWBIE >> He he :-) >> It's like when George W Bush said that : >> >> "The French can't do anything, they don't even have >> a *word* for "entrepreneur" !!" > > That's a big word for Dubya. You do know that "entrepreneur" > is (or was originally) a French word ? But he never said it! http://www.snopes.com/quotes/bush.htm Bob Ammerman RAm Systems