Actually, Pong is on my mind because I have a Velleman kit to make one, from the RS clearance. Can I solder mine up before Duane slaps a few objects together and beats me to it?
Hey, using a TV monitor is cheating! The only way Pong can be fun is if it's played on a LED matrix.
FYI, My scrolling text was all original (except for the 5x8 font). No "slapping together objects" (though I would have been happy to slap some together, if I had found any applicable objects.) I didn't use any objects from the OBEX or elsewhere. I even typed in all the ones and zero of the "Free Design" font (thicker lines than the 5x8). While the code was written by myself, I did plagiarize from some of my earlier programs.
Animate a sweep second hand going around a single 8x8 display.
With only 30 LEDs around the perimeter, you'll have to settle for the hand moving once every two seconds (on average). The second hand isn't going to look very smooth on such a small display.
With only 30 LEDs around the perimeter, you'll have to settle for the hand moving once every two seconds (on average). The second hand isn't going to look very smooth on such a small display.
Dunno 'bout no 30 LEDs around the periphery (I make 28) but of course you're right about resolution. Lines would be dreadful wavy pixellated things. But my failed investigation led to some fun making sweeping circles of various sizes in the video below.
So we're both batting 500, good enough for this town.
Dunno 'bout no 30 LEDs around the periphery (I make 28)
Well there are 15 around two sides so there must be 30 around the whole thing? I should have said there are 32 since each side has 8.
That was a nice looking spiral. What sort of algorithm did you use? Did you just eyeball it or did you calculate x and y positions?
Edit: I don't know if you see the same thumbnails on the youtube screen after your video plays as I see but it sure looks like we aren't the only ones playing with LED arrays.
Interesting video attached to Duane's icstation board web page. The guy makes SMT soldering look SO easy up to the very last pin, which gives him a devil of a time.
Interesting video attached to Duane's icstation board web page. The guy makes SMT soldering look SO easy up to the very last pin, which gives him a devil of a time.
Do they not have solder wick in China?
That was crazy. I thought he had a good system going initially but that last pin looked silly. A dab of solder wick would have cut the soldering time in half. I'm surprised they didn't redo the video. That couldn't have been a typical soldering job.
I do a lot of surface mount soldering. It's not too bad to do a lot of it by hand. The key for me is using solder wick to clean up the blobs of solder I generally leave.
It's important to get the first lead tacked down correctly. Once that's done go crazy with the solder and then come back and clean it up. It's really not very hard.
Interesting video attached to Duane's icstation board web page. The guy makes SMT soldering look SO easy up to the very last pin, which gives him a devil of a time.
I finally received my Ebay China 7219 kit from post # 21. Three observations:
1) I'm bound and determined to NOT lose the small ceramic cap that Duane lost in post #24.
2) The 8x8 display included is much bigger than the little ones that were ten pieces for $6 from post # 2. Pic attached.
3) Only 90-degree male connectors are provided on each side to chain together, so cables or an optional 90-degree female socket must be used, and a significant gap will exist between modules. Duane's 90-degree rotation to butt these together sideways is a great call on these, even if he loses capacitors. Betcha he'll find it come summertime, first time he goes barefoot.
I finally received my Ebay China 7219 kit from post # 21. Three observations:
1) I'm bound and determined to NOT lose the small ceramic cap that Duane lost in post #24.
It's not that I really "lost" the capacitor, it just sort of disappeared. I have a small time/space anomaly beneath my desk. It occasionally enlarges to engulf surface mount capacitor, resistors and pieces of heat shrink tubing. It usually doesn't go after components with leads but apparently it was extra hungry the day I went to put together the LED PBC.
3) Only 90-degree male connectors are provided on each side to chain together, so cables or an optional 90-degree female socket must be used, and a significant gap will exist between modules. Duane's 90-degree rotation to butt these together sideways is a great call on these, even if he loses capacitors.
Yeah, they're not very chaining friendly. The ones from ICStation should be better in this regard.
Betcha he'll find it come summertime, first time he goes barefoot.
Unlikely. The anomaly appears to be one directional. If the disappearing parts were just "lost" on the floor, I'd have a pile of smt caps and resistor several feet inches deep under my desk by now.
Here is a pin out of the 788BS 8x8 display. Orientation is with the writing "788BS" down.
BLACK - Common Vss
RED - Common Vdd
Thanks for the diagram Beau.
Your diagram made it much easier for me to figure out how to control the small 788BS arrays with the MAX7219 PCBs.
The small arrays I ordered over a month ago arrived yesterday. I wanted to use the PCB that came with the larger array to control the small array. After using some wire connectors between the PCB's socket and the pins on the small array, I found the two arrays did not have matching pinouts.
Using your diagram as a guide I soon found the anodes and cathodes of the arrays were opposite from each other. I've attached my edited version of your diagram to this post. I just used MS Paint to swap the red and black squares.
To wire the small arrays to the MAX7219 PCB, I swapped the row and column pins.
Here's the conversion using the notation from your diagram (the first position is the position of the PCB header the second is the position of 788BS array):
I was surprised to see the size difference of these inexpensive LEDs when erco posted his photo in post #44.
I was expecting the arrays to be the same size as Parallax's RGB array. Both of the arrays discussed in this thread are smaller than the Parallax array.
Here's a photo of four different arrays.
The one on the far left is a RGB array I purchased off ebay. I have several PCB designs for these arrays and software to control the high power shift registers. I have a thread about this project here. The PCB above the array is one I designed which includes individual data lines for each of the three colors (I don't have software for this PCB version yet).
The second array from the left is the RGB array Parallax sells.
The next array (second from right) is the array which comes with a MAX7219 chip and PCB. As mentioned elsewhere in this thread there's better (IMO) version of this kit available from ICStation.
The array on the far right is one of the small arrays available to purchase in lots of 10 for a pretty good price. The small arrays took about six weeks to arrive but I don't think this is a typical delivery time. I think they'd normally take about three weeks to arrive.
I may make a small PCB for these smallest arrays. I purchased a batch of SOIC MAX7219 chips off ebay and I'll see if I can make a board similar to the ICStation board to control the small arrays.
It's nice to have a couple of more options of LED arrays sizes to choose from. I've been meaning to add some "eyes" like Dickel's (see post #10) to at least one of my robots but the arrays I had were too large. One of these smaller arrays should be the right size.
Nice detail DD, but a failed desperate attempt at subterfuge. You still lost your capacitor. None of us have forgotten.
That poor little fellow lived its whole life waiting to be installed and be useful, contributing to man's knowledge and technological evolution. Manufactured in a communist country. Travelling in a dark, tiny mail packet across the mighty ocean and responsibly, lovingly delivered into your mailbox, tendered and entrusted into your tenuous grasp. Opened into the light of a new day into the democratic freedom of the greatest country on the planet. Eager and willing to endure the scorching heat of a soldering iron to become an integral part of the circuit for which it was specified!
Then, ignominiously lost forever into the cold, dark depths of your eternal abyss.
The capacitor is not "lost", it's "LOST". I forgot to capitalize the acronym for Localized Opening in SpaceTime. It's not my fault (that can be proven) there's wormhole under my desk.
Using Beau's diagram, I rigged up a bunch of wires to use the MAX7219 boards to drive the small arrays.
Here's a video.
The whole anode cathode swap thing seems kind of strange. They both can be driven with the same ICs (I hope), but the wiring just has to be switched around. I wonder why there's two different versions?
Edit: It just occurred to me, there's a lot more (up to 8 times) the current going through the row pins. It will make a difference which version is used. I hope the common cathode anode version isn't going to damage the MAX7219. Should these be driven with a different chip?
Excellent work, DD! I'm going to need 25 of those modules with bluetooth wireless, on my desk first thing Saturday morning. Can you comply?
What modules? The only "modules" are the ones off ebay with the bulky '7219 chip on the side.
And yes, I could get them to you by a Saturday.
I am wondering about having some PCBs make for the small arrays but I'm not sure if the MAX7219 can handle the common anode rows. I'll need to read the datasheet to make sure it can handle the switched polarity of the LEDs.
I've gotten pretty comfortable with DipTrace so let me know if you want a board made for any of these arrays.
After a bit more thinking, I'm pretty sure it won't make a difference to the MAX7219. The pins do the same amount of work whether they're connected to rows or columns.
I'm having a bit a trouble with your modules erco. I'm not sure where to fit the bluetooth?
I'm not sure there's enough space on the board for all the traces there needs to be.
Let me know if any of you seriously would like a PCB to use with the small arrays. I don't know if I want one enough to put in the effort it would require (if it's even possible).
I would probably be easier to add a connector for a ribbon cable and move the MAX7219 chips off board.
The displays are 0.8 inches on each edge. The horizontal headers take up the whole width of the display. There's a small about of room above and below the headers.
I was hoping the '7219 chip would fit within the boundaries of the display similar to the ICStation displays. It's not looking like these will be ready Saturday morning.
Ditto, (mostly). I do want to try to make a PCB for the small arrays.
I've been working at a design a bit. It might be possible to fit all the traces I'll need within the dimensions of the array, but I'm still not sure I'll be able to squeeze everything in. I suppose I could go to four layers if needed. I'm pretty sure I could get everything to fit on a four layer board.
I'll have to figure out how to link the boards. Maybe I could use some surface mount headers? The through hole headers are too close to the edge to use normal right angle connectors.
Thanks for the plug but the 7-segment displays aren't quite as symmetrical as these 8x8 arrays. I do think the MAX7219 could drive the common anode arrays but the software would need to be heavily modified. I'll probably chime in on the other thread.
Thanks for the plug but the 7-segment displays aren't quite as symmetrical as these 8x8 arrays. I do think the MAX7219 could drive the common anode arrays but the software would need to be heavily modified. I'll probably chime in on the other thread.
The hardware's all done for you, Pal, and cheap too. I have one of these in my pile of "to test" parts.
What do you know? I was able to fit all the traces onto the board after all.
I still need to clean it up and add some text but I think all the needed connections have been made. I had to break a few rules to fit all the traces on to the board. I normally don't place vias inside of a pad but as you can see most of the pads end up with a via through them.
I initially planned to place the single resistor and the capacitor on the bottom side of the board. I thought parts on the bottom of the board could cause trouble when mounting the boards so I also included pads to allow the cap and resistor to be located in the top edge of the board. The user can decide which position they'd like to use.
The boards should cost about $3.20 for a set of three at OSH Park. I'll purchase one set of three but if they work correctly, I'll probably use one of the other fab houses to have more boards made.
I like DipTrace. It's awfully fun to be able to have a custom board made so easily.
It looks like the PC is doing most of the work in that one.
I personally think these small arrays are well suited for small displays. I might try a 3x2 configuration but I'll save larger configurations for my RGB arrays.
I would be cool to use the displays for real time graphing. So far I've only graphed the number of times I press the spacebar in a given time.
Comments
Animate a sweep second hand going around a single 8x8 display.
Don't tell anyone, but I actually have over 100 8x8 RGB arrays. I intend to be playing low res PONG on a coffee Dr. Pepper table.
Hey, using a TV monitor is cheating! The only way Pong can be fun is if it's played on a LED matrix.
FYI, My scrolling text was all original (except for the 5x8 font). No "slapping together objects" (though I would have been happy to slap some together, if I had found any applicable objects.) I didn't use any objects from the OBEX or elsewhere. I even typed in all the ones and zero of the "Free Design" font (thicker lines than the 5x8). While the code was written by myself, I did plagiarize from some of my earlier programs.
Do relays count?
It doesn't matter, I wouldn't know how to do it even if I could use relays.
I thought microcontrollers were invented so we didn't have to do that sort of stuff anymore?
I've seen 7-segment displays counting up without a microcontroller in the loop. I'm pretty clueless on how one would do such a thing.
With only 30 LEDs around the perimeter, you'll have to settle for the hand moving once every two seconds (on average). The second hand isn't going to look very smooth on such a small display.
Dunno 'bout no 30 LEDs around the periphery (I make 28) but of course you're right about resolution. Lines would be dreadful wavy pixellated things. But my failed investigation led to some fun making sweeping circles of various sizes in the video below.
So we're both batting 500, good enough for this town.
Well there are 15 around two sides so there must be 30 around the whole thing?
That was a nice looking spiral. What sort of algorithm did you use? Did you just eyeball it or did you calculate x and y positions?
Edit: I don't know if you see the same thumbnails on the youtube screen after your video plays as I see but it sure looks like we aren't the only ones playing with LED arrays.
HA HA HA HA. Funny Duane.
Regarding the LED periphery count, um, just COUNT.
I just found these boards with a surface mount MAX7219.
These look like they would be easier to join together into a larger matrix.
It would have been nice if they also had mounting holes.
BLACK - Common Vss
RED - Common Vdd
...As far as the 8-line driver using discrete components, I'll post something this weekend. Think trinary ...
Sweet! Smaller and cheaper! That might be enough to make me and my old eyes get into SMT components, doggone you Duane!
Nice Find Duane!
http://static.youku.com/v1.0.0392/v/swf/loader.swf?VideoIDS=XNjA2MjQwNzgw&embedid=NzEuMTA2LjIyNS40OQIxNTE1NjAxOTUCd3d3Lmljc3RhdGlvbi5jb20CL3Byb2R1Y3RfaW5mby5waHA%3D&wd=&vext=pid%3D%26emb%3DNzEuMTA2LjIyNS40OQIxNTE1NjAxOTUCd3d3Lmljc3RhdGlvbi5jb20CL3Byb2R1Y3RfaW5mby5waHA%3D%26bc%3D%26type%3D0
Do they not have solder wick in China?
That was crazy. I thought he had a good system going initially but that last pin looked silly. A dab of solder wick would have cut the soldering time in half. I'm surprised they didn't redo the video. That couldn't have been a typical soldering job.
I do a lot of surface mount soldering. It's not too bad to do a lot of it by hand. The key for me is using solder wick to clean up the blobs of solder I generally leave.
It's important to get the first lead tacked down correctly. Once that's done go crazy with the solder and then come back and clean it up. It's really not very hard.
Step 1.. Use Rosin. !
Step 2. Bang the board on the desk while the solder is hot. That will get it off.
It's my patented technique from the 70's, sadly my patent has run out. You are all free to use.
1) I'm bound and determined to NOT lose the small ceramic cap that Duane lost in post #24.
2) The 8x8 display included is much bigger than the little ones that were ten pieces for $6 from post # 2. Pic attached.
3) Only 90-degree male connectors are provided on each side to chain together, so cables or an optional 90-degree female socket must be used, and a significant gap will exist between modules. Duane's 90-degree rotation to butt these together sideways is a great call on these, even if he loses capacitors. Betcha he'll find it come summertime, first time he goes barefoot.
It's not that I really "lost" the capacitor, it just sort of disappeared. I have a small time/space anomaly beneath my desk. It occasionally enlarges to engulf surface mount capacitor, resistors and pieces of heat shrink tubing. It usually doesn't go after components with leads but apparently it was extra hungry the day I went to put together the LED PBC.
I didn't know the other arrays were so small. That's cool.
The sell just told me they're sending me another batch of 10 since the first batch never arrived.
Yeah, they're not very chaining friendly. The ones from ICStation should be better in this regard.
Unlikely. The anomaly appears to be one directional. If the disappearing parts were just "lost" on the floor, I'd have a pile of smt caps and resistor several feet inches deep under my desk by now.
Thanks for the diagram Beau.
Your diagram made it much easier for me to figure out how to control the small 788BS arrays with the MAX7219 PCBs.
The small arrays I ordered over a month ago arrived yesterday. I wanted to use the PCB that came with the larger array to control the small array. After using some wire connectors between the PCB's socket and the pins on the small array, I found the two arrays did not have matching pinouts.
Using your diagram as a guide I soon found the anodes and cathodes of the arrays were opposite from each other. I've attached my edited version of your diagram to this post. I just used MS Paint to swap the red and black squares.
To wire the small arrays to the MAX7219 PCB, I swapped the row and column pins.
Here's the conversion using the notation from your diagram (the first position is the position of the PCB header the second is the position of 788BS array):
PCB Pin #, PCB position, Array Position (788BS pin #)
1, R5, C5 (pin 6)
2, R7, C7 (pin 15)
3, C2, R7 (pin 2)
4, C3, R6 (pin 7)
5, R8, C8 (pin 16)
6, C5, R4 (pin 12)
7, R6, C6 (pin 11)
8, R3, C3 (pin 4)
9, R1, C1 (pin 13)
10, C4, R5 (pin 1)
11, C6, R3 (pin 8)
12, R4, C4 (pin 10)
13, C1, R8 (pin 5)
14, R2, C2 (pin 3)
15, C7, R2 (pin 14)
16, C8, R1 (pin 9)
I'm currently uploading a video of the small arrays scrolling text. It also shows the wire harness I used to connect the array to the PCB.
I was expecting the arrays to be the same size as Parallax's RGB array. Both of the arrays discussed in this thread are smaller than the Parallax array.
Here's a photo of four different arrays.
The one on the far left is a RGB array I purchased off ebay. I have several PCB designs for these arrays and software to control the high power shift registers. I have a thread about this project here. The PCB above the array is one I designed which includes individual data lines for each of the three colors (I don't have software for this PCB version yet).
The second array from the left is the RGB array Parallax sells.
The next array (second from right) is the array which comes with a MAX7219 chip and PCB. As mentioned elsewhere in this thread there's better (IMO) version of this kit available from ICStation.
The array on the far right is one of the small arrays available to purchase in lots of 10 for a pretty good price. The small arrays took about six weeks to arrive but I don't think this is a typical delivery time. I think they'd normally take about three weeks to arrive.
I may make a small PCB for these smallest arrays. I purchased a batch of SOIC MAX7219 chips off ebay and I'll see if I can make a board similar to the ICStation board to control the small arrays.
It's nice to have a couple of more options of LED arrays sizes to choose from. I've been meaning to add some "eyes" like Dickel's (see post #10) to at least one of my robots but the arrays I had were too large. One of these smaller arrays should be the right size.
That poor little fellow lived its whole life waiting to be installed and be useful, contributing to man's knowledge and technological evolution. Manufactured in a communist country. Travelling in a dark, tiny mail packet across the mighty ocean and responsibly, lovingly delivered into your mailbox, tendered and entrusted into your tenuous grasp. Opened into the light of a new day into the democratic freedom of the greatest country on the planet. Eager and willing to endure the scorching heat of a soldering iron to become an integral part of the circuit for which it was specified!
Then, ignominiously lost forever into the cold, dark depths of your eternal abyss.
Is there a SPCC?
Adafruit Bicolor LED Square Pixel Matrix with I2C Backpack
http://www.adafruit.com/products/902#Description
Tutorial: http://learn.adafruit.com/adafruit-led-backpack/bi-color-8x8-matrix
The capacitor is not "lost", it's "LOST". I forgot to capitalize the acronym for Localized Opening in SpaceTime. It's not my fault (that can be proven) there's wormhole under my desk.
Using Beau's diagram, I rigged up a bunch of wires to use the MAX7219 boards to drive the small arrays.
Here's a video.
The whole anode cathode swap thing seems kind of strange. They both can be driven with the same ICs (I hope), but the wiring just has to be switched around. I wonder why there's two different versions?
Edit: It just occurred to me, there's a lot more (up to 8 times) the current going through the row pins. It will make a difference which version is used. I hope the common cathode anode version isn't going to damage the MAX7219. Should these be driven with a different chip?
What modules? The only "modules" are the ones off ebay with the bulky '7219 chip on the side.
And yes, I could get them to you by a Saturday.
I am wondering about having some PCBs make for the small arrays but I'm not sure if the MAX7219 can handle the common anode rows. I'll need to read the datasheet to make sure it can handle the switched polarity of the LEDs.
I've gotten pretty comfortable with DipTrace so let me know if you want a board made for any of these arrays.
After a bit more thinking, I'm pretty sure it won't make a difference to the MAX7219. The pins do the same amount of work whether they're connected to rows or columns.
I'm having a bit a trouble with your modules erco. I'm not sure where to fit the bluetooth?
I'm not sure there's enough space on the board for all the traces there needs to be.
Let me know if any of you seriously would like a PCB to use with the small arrays. I don't know if I want one enough to put in the effort it would require (if it's even possible).
I would probably be easier to add a connector for a ribbon cable and move the MAX7219 chips off board.
The displays are 0.8 inches on each edge. The horizontal headers take up the whole width of the display. There's a small about of room above and below the headers.
I was hoping the '7219 chip would fit within the boundaries of the display similar to the ICStation displays. It's not looking like these will be ready Saturday morning.
I put in a plug for my hero DD at http://forums.parallax.com/showthread.php/152890-Common-Anode-displays.-what-would-you-do?p=1232456&viewfull=1#post1232456
Ditto, (mostly). I do want to try to make a PCB for the small arrays.
I've been working at a design a bit. It might be possible to fit all the traces I'll need within the dimensions of the array, but I'm still not sure I'll be able to squeeze everything in. I suppose I could go to four layers if needed. I'm pretty sure I could get everything to fit on a four layer board.
I'll have to figure out how to link the boards. Maybe I could use some surface mount headers? The through hole headers are too close to the edge to use normal right angle connectors.
Thanks for the plug but the 7-segment displays aren't quite as symmetrical as these 8x8 arrays. I do think the MAX7219 could drive the common anode arrays but the software would need to be heavily modified. I'll probably chime in on the other thread.
The hardware's all done for you, Pal, and cheap too. I have one of these in my pile of "to test" parts.
http://www.ebay.com/itm/MAX7219-Red-Module-8-Digit-7-Segment-Digital-LED-Display-Tube-For-Arduino-MCU-/360794796766?pt=LH_DefaultDomain_0&hash=item54010bb2de
I still need to clean it up and add some text but I think all the needed connections have been made. I had to break a few rules to fit all the traces on to the board. I normally don't place vias inside of a pad but as you can see most of the pads end up with a via through them.
I initially planned to place the single resistor and the capacitor on the bottom side of the board. I thought parts on the bottom of the board could cause trouble when mounting the boards so I also included pads to allow the cap and resistor to be located in the top edge of the board. The user can decide which position they'd like to use.
The boards should cost about $3.20 for a set of three at OSH Park. I'll purchase one set of three but if they work correctly, I'll probably use one of the other fab houses to have more boards made.
I like DipTrace. It's awfully fun to be able to have a custom board made so easily.
Try this next: http://www.youtube.com/watch?v=r7jDyz4gjSs#t=136
We tried that, but once their pictures start appearing on milk cartons we return them.
It looks like the PC is doing most of the work in that one.
I personally think these small arrays are well suited for small displays. I might try a 3x2 configuration but I'll save larger configurations for my RGB arrays.
I would be cool to use the displays for real time graphing. So far I've only graphed the number of times I press the spacebar in a given time.