question about my propeller board
Badger
Posts: 184
Hello
can someone please look at the schematic below and tell me if it will support a 15 or so led chaser light chain.
please
thanks in advance.
Badger
can someone please look at the schematic below and tell me if it will support a 15 or so led chaser light chain.
please
thanks in advance.
Badger
727K
Comments
Anyway, I don't know why it wouldn't as this is quite a simple application really, just use a display driver like a TLC5920DLG4 (or similar, there are dozens like this) and connect to appropriate pins, then write the software that you need! I note this is battery powered, that will only run LEDs for so long before the supply is depleted of course. What's the application?
i am trying to build a robot with a Christmas theme. I wanted to put red, green, and blue led's on the front and sides and make them do like chaser patterns or something. the robot is simple just collision detection using a sonar sensor. I dont have any other senors or do i have money to buy any ir detectors. I wish i had the correct chips here to do that. I have a sx chip and a wireless bread board and such. I also dont have a lot of know how .. I had to use all the money my robot budget had to buy the tracks, motor controller, and gear transmission. but there it is in a nut shell. I was hoping to use the board it self. the kia278 r05p1 and kia278 r33p1 chips on this board are the 3.3 and 5 volt chips the specs say they are good for 2 amp each and 15 watts of disipation with heat sink which i have to get and put on there. I have some of those laying around i can use. if you have any ideas or schematics you can point me to let me know ok .. I have to take my sons friend home i will be back in about 40 minutes
Badger
What kind of resisters should i use between the pins and led's and if possible to run 2 led's per pin.
Badger
Either you misread Kwin ... or typed it wrong...
He's worried that you can't source enough juice to your LED's ... depends on how many LED's you are going to light at once and what kind of LED's... he is probably spot on.
If you need more umph... you need to add a transistor to supply the extra current. the cheaper the better...
you then tie the base to your pin.. run your extra supply through your LED, ground everything together and you are good to go.
The question is what is the cheapest transistor that will work for you.... that's one for the real hardware guys[noparse]:)[/noparse]
Rich
i read it wrong .. i dont ware my reading glasses all the time . this is my bad LOL thanks for catching that and thanks for correcting that mistake.
hey take a look at the first post in this thread and look at the board. it is different that any parallax sells it is from an over sees company called inex. or inex.com. Tell me what you think. I posted the schematic of the board as i said in the first post. i have looked up the 2 power regulators they will carry 2 amps of current and will give off up to 15 watts of heat with a heat sink. tell me what you think if you would ok
Badger the blind
standard LEDs consume 20 mA at 1,7-2,0V. Two LEDs per channel with 15 channels makes 15 * 2 * 20 mA = 600mA all.
As the manual and datasheet says the chip can stand 30 mA per IO-Pin and 100 mA per 8 IO-Pins. So two LEDs per Pin is too much
Now there are low power = low light LEDs with 2mA. And nowadays all kinds of high power LEDs
As transistors for 20 mA any kind of standard NPN-Types will do. As I'm from germany I'm only familiar to european types like BC548 or similar
maybe 2N3904
The resistors depend on the current and voltage-specification of the LEDs.
Driving standard LEDs with 20mA at 1,7V from a 5V Supply means
(5V - 1,7V) / 0,02A = 165 Ohms per LED
if you have two LEDs parallel then the current is 40mA meaning (5V - 1,7V) / 0,04A = 82 Ohms
If you don't know much about electronics I highly recommend that you test your LEDs carefully
with higher resistors and a multimeter to find the right values and doing a final test with a circuit
that simulates an IO-Pin from the propellerchip. A simple switch that switches on/off 3,3V and measuring
the voltages and current if everything is OK.
best regards
Stefan
thanks for the good information there . i am in classes to learn electronics. i just happen to have a 2n3904 h331 transister, adjustable voltage regulator (lm317t), darlington transistor (tip120) and a mosfet transistor n channel 60 volt. (irf510) now if any of these will work can someone give me a schematic on how to do this circuit. i have an assortment of resisters even an parallax sx28ac/dp , l7805cv and an sn74ls47n an asortment of caps. a boe, a hwb, the board i have listed and a hydra and an ARMmite board . i hope we can figure out something .. do you thank you or someone can help me out with a schematic that will do a 15 light chaser led string or something like that. can be pin to pin as well
Badger
i hope you can make heads or tells out of the above
I don't know enough about electrons to comment on the design... but I think you are looking for feedback on configuration as well as implementation. (I even had to google qp410... so please take my comments in light of this factoid[noparse]:)[/noparse]
three channels for ADC...[noparse]:)[/noparse] we want more[noparse]:)[/noparse]
Having the SD card is a HUGE plus to me, and I really like the power supply options...
This board looks fabulous to me but...but let me include of a list of things I'd like to see, either now or later... everything above AND
It would be nice if you would also bring the vga pins out to a standard connecter ... as in your port 2 for people that don't use VGA and habitually run out of pins...
your board only has 1 prop...
BUT you are bringing 5 volts out to port 2... so in theory you could have a port that would accept a 4D systems uoled-prop96, a second prop... for people, who habitually run out cogs... using the same pins as your VGA port and then allow the user to select between the two options with jumpers or switches... the other port would be multipurpose... just set up to be compatible with 4D's 96 pins... and then bring all of the 4D's pins out to a 10 hole header... if you don't want to do that... you could make the board "96" compatible by just changing assignments in port 2.
Same comment about the USB port... it would be nice to have jumpers to recapture the two pins, when you don't need the USB anymore.
Everybody complains about EEPROM space... adding in a short EEPROM daisy chain would be nice.
Everybody is price sensitive... put the prop on a socket and have your beginning price be the board without the Prop[noparse]:)[/noparse]
Rich
thanks and yes there could be more added to the board as you have said. but the price is what sold me i paid 79.99 for the board and i think about 7 or 8 shipping this is all us. i bought it off ebay but you can go to www.micro4you.com and check out all they have for sell there. just thought i would let you know.
Badger
I honestly thought you were in the design phase on this...[noparse]:)[/noparse] LOL
ROFL
http://stores.ebay.com/Micro4you-Store
Post Edited (rjo_) : 10/20/2008 1:15:29 AM GMT
I still go back to my original post; a LED driver is needed for this application, as for cost, these chips typically run to around 3 dollars or so, I would be very surprised if you were able to implement a discrete solution (that is to say transistor-based) for the same money, frankly. And they are designed for the exact job at hand, largely eliminating power consumption worries, etc. Overal consumption could be reduced by only ever turning on (say) half of the LEDs at one time.
@rjo_ : yep, I had to google that chip too, never heard of it before!
www.parallax.com/Resources/NutsVoltsColumns/NutsVoltsVolume6/tabid/449/Default.aspx
with discret transistors you need 15 transistors for 15 channels (every channel wnats to be switched on/off separately
ICs like th euLN2803 are a good choice.
It's ok to ask questions what ever you like.
As you are in classes to learn electronics, one thing beneath electronics is to learn to manage things yourself.
As an engineer everybody expects you to do the basic things yourself and get info yourself (by the help of other people
but managed by yorself) Your already on your way doing this by asking in this forum. I want you to improve
your abilities of doing that.
Managing things yourself does NOT mean never ask somebody again. But make the first step yourself.
Here the next steps can be: go on googling for example circuits for LED and ULN2803 yourself
If you have no access the questions could be
hello experienced internetresearchers: "what is the way of thinking for keywords how to find democircuits about LEDs ?"
or maybe can somebody post a link to a circuit-collection with things like driving LEDs ?
to keep the activity in your hands go and make a googlesearch on keywords like LED example circuit
this is your first step
then come back with some circuits wich you attach as pictures or as img-urls and ask the question
"which circuit would you recommend?"
Or questions like am I right the resistor R3 in this circuit is for .... How does it have to be changed that ....
best regards
Stefan
Thanks again for your alls help (sorry about the country jabber there) Stefon I will do as you say. I just needed some info as to ware to start. It would have been nice to have some schematics to compare that is a lot more closer as to what i am looking for, but i will goodle my little heart out LOL. and try.
Badger
a question using each of the following how would i calculate what resisters to use before and after each of the following adjustable voltage regulator (lm317t), darlington transistor (tip120) and a mosfet transistor n channel 60 volt. (irf510) this question is what i thing Stefon was telling me to ask. I wish i had 3 or 4 darlington arrays but cant get them at this time.
also when a cpu pin goes low is there any reverse spike from an led do i have to put a diode in with each transistor. All of the above came from Radio Shack (rat shack) if that helps with the answers
Badger
your question is somehow unprecise
OK I try to guess what you might mean.
an LM317 is REALLY for power-SUPPLYING NOT for powerswitching
to get answers about resistors for LM317 it is very often the same way:
Download the datasheet
to have an easier start I attache it to this post
take a look inside the datasheet and ask a more detailed question.
The resistors for transistors depend on several things
type of transistor
required current from collector to emitter
there is no easy answer that fits for 90% of all cases
I'm a hobby electronist know for 30 years with a medium level of knowledge
to answer your questions about the resistors for the transistors I would have
to download the datasheets myself take a look inside and start calculations
This is easy to do but timeconsuming which I don't have.
Let the forum see that YOU made more activity than just
posting a new question. especially I want to see some infoRESEARCH
done by YOU.
Make your question as CONCRETE as possible.
A satisfying answer to your previous question would be
a 5 pages long tutorial about the elementary basics of transistors
From your questions I can see that you are a real beginner.
That's OK but I have to make a correction about asking questions.
I'm even thinking that things like current = voltage divided resistance is new for you.
If this is the case go googling for basics of electronics
Starting a microcontroller-project with not knowing current = voltage divided resistance
is like if a four year old child that hardly can ride a bike wants to ride with free hands juggling balls at the same time.
I guess it will take some overheated LM317's, transistors, damaged propellerchips with that less knowledge
microcontrollers are still similar to PCs somhow but there's much more to know than plug in/out usb-cables and installing drivers
I hope this does not sound harsh. It's my point of view.
By this way I'll take it for serious that you can LEARN a lot.
Doing every detail for you - for me - would be treating you as a five year old child
and would keep you thumb and in the state to ask for every little detail again and again beeing dependent on others
best regards
Stefan
Post Edited (StefanL38) : 10/21/2008 7:04:03 PM GMT
first of let me say you dont sound harsh. you sound like someone that would like to see me go forth and be fruitful. By explaining what you have, it seems that you are trying to help me not to make others here frustrated with my by holding my hands through every thing.
with that said.
I under stand that current = voltage divided by resistance that is ohm's law. What i dont understand one is how transisters work which one should i use for my project.
project =
building a robot that has a sonar sencer to try to avoid running into something. I wish i could afford or build a couple of ir sencers but that is above me for the time being.
what i am looking for right now is how to set up a strand of led's that looks like a chaser lights. All led's on and the cycle one off then on then the next one off then on ect.
what i under stand this is way to much current for a microcontroller even one like mine that says it will handle 2 amp of current on a continuous basis.
so i need to step up the current somehow on each pin to run the led. Now sense i am supplying power to each led through a transister i would like to make it 3 led's per pin so now i have to make sure that enough current is flowing to the led's and only turned on and off by the pin. just like my motor controller does.
so i guess i dont understand transisters, for one and i dont understand transister in relationship to resisters.
i know that resisters cause a voltage drop from in to out to contral how much voltage that goes into the load resistance
i guess i need to learn more about transistors i just wanted an idea of how these work together then i would build the circuit then get more ideas and do somethings on my own with my own research.
i just need to understand how this works 5volts form a pin to a transistor it boost the current out to run the load resistance i guess i just wanted to see a very simple circuit built this way and then i would go from there.
Badger
i hope you get the the meaning of what i am trying to say StafonL38
thanks for that link 40 short videos for doing little diy stuff like that. That will help me alot
thanks again my friend I am a hands on learner. My whole life has been dedicated to network engineering with just a touch of software development. I have not college education nor have i went to college for any of what i did for a living. I had my own 10 pc computer lab with all kinds of server software. That is ware i learned about token ring, fiddi, 10bt tp, 10b2 (coax) topologies, protocols, arc net, monolithic type drivers, dos memory management .... you get the idea so i need a base of learning to get started with out to much destruction if you know what i mean. I will proceed thanks. if you have any other links like this please pass them along. I will put them into my electronics studies folder in book marks
thanks again for reading my broken sentence structures and the way i think in broken thought strings.
Badger
it took me a while to find this websites. (as I decided myself to start this research MeMyselfandI are responsible for spending time on this
there are a lot of websites telling things about transistors in a more or less sophisticated style or theoretical style
as introduction for hobbyelectronics they are not suitable
but finally I found pages by googling
basics about transistors
this one I think is good
www.wisc-online.com/objects/index_tj.asp?objID=SSE3703
start experimentating with the LED-circuit here
you need one or two multimeters to do that
www.kpsec.freeuk.com/trancirc.htm
maybe additional but alredy some kind of sophisticated
www.mitedu.freeserve.co.uk/Design/bjtsw.htm
www.allaboutcircuits.com/vol_3/chpt_4/2.html
www.electronics-tutorials.ws/transistor/tran_4.html
best regards
Stefan