Micros: something obvious I'm missing I'm sure. - Page 1
Forum section: electronics / general

author: releasethesmoke
author_rank: Newbie
timestamp: February 08, 2019, 04:04:18 pm
content: Greetings all,Long time lurker, first-time poster. I was watching Big Clive's video about a rather plastic piece of junk kid's toy which yielded a rather inexpensive way to obtain a full-color LED video wall panel on the cheap. You can see said video here:Needless to say, I bit and bought one off the usual e-commerce site. The toy itself and supporting apps are rubbish but the panel seems to be pretty common (Adafruit sells a variant) and it does come with a blob on the chip unknown micro to drive it.Not being a fan of junking things, I was curious to see if the existing board could be reused since it already contains a working LED matrix driver. This being said, my knowledge of microcontrollers is, well basic outside of piping code to an Arduino. On the board itself there seems to be a place for a header with the pin identifications silkscreened as 5V, GND, SDA, SCK, and VPP.Being a blob on the chip doesn't make identification possible w/o risk of destroying what the chip underneath is but the SDA, SCK, and VPP appear to be terminating there. I soldered a header to the pins and attempted to poke around with the limited tools I have (just about everything I own is in storage at the moment) and it doesn’t seem to be I2c, doesn’t seem to be TTL serial, and it seems like too few of pins for ICSP despite the VPP pin.It may be that I can't do squat with this, but I'd like to give it another shot and possibly expand my limited knowledge. Any gentle nudges into another direction of thought would be most welcomed.Thank you!

author: nsrmagazin
author_rank: Regular Contributor
timestamp: February 08, 2019, 06:45:25 pm
content: Post a few pictures please.The MCU would have to be programmes, you need a new one probably that you can program.It mightt be cheaper to buy a new ready board, when I see your pictures I will look for one.

author: releasethesmoke
author_rank: Newbie
timestamp: February 08, 2019, 07:42:34 pm
content: Thank you nsrmagazin,Here are the dissected bits:

author: tsman
author_rank: Frequent Contributor
timestamp: February 08, 2019, 07:51:20 pm
content: You may need to do something on VPP to enable the programming interface like feed it a high voltage. I doubt it is I2C. They're just using the SDA and SCL labels for serial data and serial clock.Probably not worth spending the time trying to identify the uC under the epoxy blob as you only have 1 unit and there is a high chance it is some weird China uC that only has Chinese docs.

author: mariush
author_rank: Super Contributor
timestamp: February 08, 2019, 08:20:34 pm
content: You don't need to reverse engineer it, the led board is documented, I think Clive even explained how it works in a video.The microcontroller is basically pushing a series of bits to turn leds on and off, and shift registers or whatever those chips are on the led board push the bits along from one to the next. When you're done sending bits for a whole row, you use the latch pin to change the whole row instantly.You have on the back of the board the meaning of each pin in that 2x10 connector, and Adafruit even has wiring diagrams and arduino library :https://learn.adafruit.com/32x16-32x32-rgb-led-matrix/overview

author: releasethesmoke
author_rank: Newbie
timestamp: February 08, 2019, 08:32:39 pm
content: Yes, I realize that; however, as had mentioned in my first post, it was more of an educational exercise since it was already there (and presumably with a decent-ish low power driver).Ultimately if that's the way to go, then it is what it is, but if there is potential to figure something out, I'd like to do so.Thanks!

author: nsrmagazin
author_rank: Regular Contributor
timestamp: February 09, 2019, 07:39:50 am
content: EDIT:Using a different MCU with the same LEDs can work, but its hard to find out how to program it and how to connect it. You can try.Try to follow the instructions in the video or find a similar video.You can buy the LEDs and the MCU and program it by yourself.http://www.cfcbazar.com/?s=5mm+LED+Diode+Kithttp://www.cfcbazar.com/?s=PIC16F877AYou can try this LED cube kit:http://www.cfcbazar.com/products/diy-electronic-3d-multicolor-led-light-cubeeds-kit-with-excellent-animations-3d8-8x8x8-gift-led-display-electronic-diy-kit/

author: LukeW
author_rank: Frequent Contributor
timestamp: February 10, 2019, 12:20:39 am
content: The data, clock, and Vpp programming interface sounds a lot like a PIC microcontroller ISP interface.

author: sokoloff
author_rank: Super Contributor
timestamp: February 10, 2019, 01:47:22 am
content: BigClive video is not available at the moment.What's the name of the kids' toy?

author: tsman
author_rank: Frequent Contributor
timestamp: February 10, 2019, 02:29:49 am
content: Quote from: sokoloff on February 10, 2019, 01:47:22 amNot sure why you can't see the video as it is definitely still up. It is aProject Mc2 Pixel Purse.It isn't a very good deal now because all the vendors have hiked up the prices to what thebare panel costs from Adafruit. You can buy the same 16x32 LED panels from China for less than half the current price. Advantages of buying the toy are that you get it quick and you get a plastic diffuser.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: February 10, 2019, 08:40:38 am
content: I bought a couple of these for £2 which plug into a RPI Zero.https://www.electrodragon.com/product/rgb-matrix-panel-drive-board-raspberry-pi/

author: Simon
author_rank: Unknown
timestamp: February 10, 2019, 03:43:28 pm
content: I would bet it is a PIC, check the pin order to the pinout of a pickit to see. But yea, no point in investing time in this. If you want to learn microcontrollers then pick one and start experimenting.

author: MarginallyStable
author_rank: Regular Contributor
timestamp: February 10, 2019, 08:11:38 pm
content: I designed "feather wing" and use a feather M0 proto to drive these displays.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: February 10, 2019, 09:39:34 pm
content: Interesting fit with the Corsair case. What’s the story ?

author: MarginallyStable
author_rank: Regular Contributor
timestamp: February 10, 2019, 10:57:25 pm
content: Basically a system status display. Each colum bargrah represents the cpu usage of a single core on my 16core system. The upper most left led is hdd activity indicator, second line horizontal bargraph is total cpu useage, third line horizontal is memory usage. Forth line is a binary clock.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 11, 2019, 06:09:36 am
content: I had a go at reverse engineering the communications protocol, but ended up not bothering with reusing the existing controller since it's very limited.https://www.eevblog.com/forum/projects/reverse-engineering-mc2-led-toy-purse/An explanation of how the LED panel works and how to drive it: