Can someone check my schematics for my POV display project? i used eagle light edition. Attached is the image of the schematics and the .sch files.
I am not sure if the decoupling capacitors are placed right.
More detail to my project is on the post:
http://forum.arduino.cc/index.php?topic=228843.0
Thanks.
POV circuit.zip (592 KB)
Since the advent of TTL in the 1970s, the convention has always been to layout the pcb with the pads for the decoupling caps RIGHT NEXT TO THE CHIPS AS CLOSE AS IS PHYSICALLY POSSIBLE. I rather doubt this has changed, so to answer your question, your caps are there but since I can't open an Eagle file I don't know WHERE they are, only that they are connected to the power bus. If the purpose of having decoupling caps is to prevent glitches in the operation of the chips, the caps should be so close to the chip that you can just slide a piece of paper between the cap and the chip. In other words , within 5 mm of the chip.
10000 x 6000 pixels? That's way too big to view here. Resize to 1000 wide.
@raschemmel,
Download the free version of Eagle, then you can look at files.
http://www.cadsoftusa.com/download-eagle/?language=en
@account001 ,
You didn't include the .brd file, so the board layout can't be reviewed.
@Crossroads,
Do you agree with what I posted in Reply#1 ?
Yes, decoupling caps right next to the Vcc pins.
If 0.1" perfboard is used as an example, then the cap pin will be 0.1" from the Vcc pin.
1 cap for each VCC pin on a board.
Thanks for the replies, sadly i haven't yet made the pcb board yet so no .brd files. The eagle light version has limited board dimension for making the pcb and does not suit my project so i need to export the .sch to another program and make the board. i am planning to use designspark pcb.
I will place the decoupling caps right next to each chip. hopefully i will finish making the board soo so i can upload it. And was there anything wrong with the schematics along?
Schematic looks ok, I didn't trace out all the control lines.
IC1 needs more decoupling caps - one per each VCC & AVCC pin. You're 2 short.
So you're putting a '328based module, a 644 surface mount part and thru hole shift registers - why not put the 328 on directly and go surface mount with the shift registers as well?
Why the mix of shift register types? 4 are smaller package than the rest.
Holy smokes batman ! I can see the smoke coming off that board from here !
(maybe you should consider spacing out the driver chips a little more. I would expect a lot of heat build up with them so close
together. @Crossroads, what do you think ?
I only layed it to check the fit.
Heat - really depends on how much current per each LED.
It's a POV thing? I don't know what it will look like.
The atmega 644 is part of the microduino, left part of the schematics are the microduino's own schematics, i just copied and paste. the shift registers are thru holes because i sample the through hole version and back then i was planning to use the soldering iron to solder everything together and didn't want that many smd parts. the mix of shift register was because i can only sample 5 of each chip. i have been told this is unfair practice and this is one time only, i live in AUS and parts ordering can be expansive. and yes i would probably use double layer.
sorry about the image size of int he first post, i didn't realize people would view it on the browser. it worked fine using a image viewer.
Ok, making more sense now.
How's the conversion to designspark going?
regarding its look: the pov display has a cylinder shape. the link is to another post which had the appearance description, you may need to read a bit, read reply #6 and reply#1
microduino(Atmega1284p) with tlc5940 data throughput calculation help needed - Project Guidance - Arduino Forum i want to place the shift register and LEDs on three separate arms and the micorduino on the base. the display will spin at around 25-40 revolution per second, not sure if that would be able to cool down the chips if their heat up.
i drew the layout for the arms, a general idea for the layout of the arms. Would the chips be too close in that case? sorry about the quality.
the conversion is yet to happen. but there is a ulp file which converts the .sch from eagle to design spark pcb
http://www.rs-online.com/designspark/electronics/tutorial/importing-eagle-designs
this is my first time making a pcb so it may take sometime. i will post the board here soon.
Sounds like expensive PCBs. How long are you expecting them to be?
Heat won't be an issue, not with just 20-30mA per LED, and with POV multiplexing they are only on part time anyway.
maybe 20cm ? i would not add silk screen and solder mask, to reduce the cost. Not sure how spaced out the LEDs would have to be with out the solder mask, i decided to use solder paste and not soldering iron.
And about the "
POV multiplexing
, multiplexing would be too slow, but yes the LEDs are flashing and not constantly on.
i need to check the schematics on a bread board before i sent off the pcb, is there any program i can run to test the setup, just using 1 of each of the 3 different TPIC6x595 chips. i have not done any programming for the arduino(micorduino) yet, and have no experience.
i still have not got the microduino but i should get it next week. it is taking a long time.
