Tuesday, December 24, 2013

RGB LED Persistence-Of-Vision Display (PIC12F629 & WS2812Bs)

I played around at creating a POV display with red LEDs before - I really want to make another using 24 WS2812B RGB LEDs. So, since I lack parts, I decided to draw up plans. No hardware or software yet - just plans :)

The big question - since the LEDs are addressed serially, and there's 24 LEDs x 24 bits apiece (576 bits total), and the serial bus has a speed of 800Kbps - will I be able to address all of the LEDs in time, or will there be a visually perceptible lag between LED 1 and LED 24?

Wednesday, December 4, 2013

Fun With A PIC, LEDs, And A Motor

This is a couple of years old, but I never posted it. So, for posterity, here is my attempt at a 'persistence-of-vision' display. Only 5 LEDs on a spinning arm, and definitely a junkyard build, but effective. I used a micro-switch that was bumped every revolution as my '0 degree' indication, which made a lot of noise and reduced the revolutions a bit. It would have been better if I had used a 'hall-effect' sensor (but I didn't have one) or even an infrared emitter/detector. Next revision?


Friday, November 15, 2013

Typhoon Yolanda Relief

If you are considering donating monies for Typhoon Yolanda relief, I would ask you to consider donating to this charity in Davao City.

From a friend of mine who lives in Davao City and works with the Family Circus outreach:

It's been an honor to work with Darrell & Sandy Blatchley as well as their son Darrell every week at the Family Circus outreach to the poor of Davao City. I need to ask those of you who pray to remember Sandy & Darrell, Jr. They are on their way to the areas struck by the typhoon. One of their tasks will be to handle bodies of the deceased. This is a potentially dangerous mission, because there's the possibility of violence as rescuers meet desperately hungry survivors. Again, I'm honored to know them, & again, please pray for "DD" & his mom.

Homepage: http://familycircus.org/
Donations: http://familycircus.org/html/donations.html

Sunday, August 11, 2013

Baby Crib Toy

My wife and I are enjoying the company of our new son - Ethan Christopher - who is almost 3 weeks old. We bought a crib for him the other day with one of those wind up crib toys that he can watch and listen to and (hopefully) be entertained.

The problems are:
1) It needs to be wound up. Constantly. If it stops, Ethan cries.
2) It only has one song.
3) There is no control of the song volume.

So, I am going to take the 'Cat Ball' design and make a crib toy out of it. Hopefully I can find all of the bits and pieces I need to do this project.

Plus, my lab is a mess. Actually, my lab is now a big messy pile of junk in one corner of the old flat. We turned the new MadLab office space into our bedroom, because we were able to easily seal off the room and add air conditioning. Which means before I put the project together, I have to put the MadLab back together first. Somewhere. I haven't figured out where, yet.

Saturday, March 16, 2013

Apologies For The Lite Blogging Lately

I've been under the weather and we have also be doing some more construction around the MadLab, so not much opportunity to hack or post. But - the MadLab patio/kitchen is looking _much_ better

Friday, February 8, 2013

FM Radio (PIC12F1840) Using A TEA5767 or RDA5807P Module

UPDATE 13.0209:Here's some links for information about the RDA5807P and module:
RDA5807P Datasheet
Quick Info Sheet on a RDA5807P module. It does NOT look like the one I am using.
RDA5807 Programming Manual - unfortunately, it's in Chinese

And here's some links for the TEA5767:
TEA5767 Application Note
TEA5767 Datasheet

The RDA5807 can operate in native (RDA5807) mode or emulate the TEA5767. So the datasheet for the TEA5767 is a good source for registers and bits.

Here's a quickie project using a PIC12F1840, an RDA5807P module (although a TEA5767 module could be used), a 2x16 I2C LCD module and an IR receiver. FM Radio! I haven't played around with all of the module settings yet - but I have power on, power off, scan up, scan down, mute, and toggling HLSI mode.

Thursday, January 17, 2013

Hacking An Atari Lynx

Update 13.0214:
My niece gave me a bunch of old PC boards, one being a ISA bus sound card. And - it had a 74LS245 on it, although not a DIP package. Well, that works for me - I wired it in to the design (instead of a 540) and only to /CE0. I will wire both /CE0 and /CE1 when I find a 74LS08. Well, I may be able to wiring in both using diodes, but I need to do some research.

 The 74LS245 hot glued to the interface board and
blue wires attached to the 'B' side of the chip.

  The 74LS245 fully wired into the design.

Success! This is T-Tris, running on the new setup.

So, with the 74LS245 incorporated, I don't have to do a bunch of weird 'bus switching' code in the PIC. It simplifies the code dramatically, which is needed. Next is to incorporate either the USB for reading game images from a thumb drive, or an SD Card slot. OR figure out how to increase the storage capacity of the PIC some other way (right now it's 32K bytes minus 256 bytes for code and 64 bytes for a header).

Games running so far:
1) Pong1K
2) Karri's PONG
3) Centipede
4) T-Tris

I still haven't managed to get the BLL loader working. BUT - I _can_ load either pure cart images, 'LYNX' header images (for emulators) and 'BS93' images (again, for emulators).

Update 13.0131:

New ROM Emulator schematics, V1.01 (5 pages). Now I need to find the parts - how am I going to find a 74LS540 and a 74LS08 around here? Time to scrounge at the local repair shops.

Update 13.0131:
I need to add a tri-state buffer to the data lines, that is enabled when either CE0/ or CE1/ go low. Right now the PIC drives the data lines continuously and this messes with the buttons - and who knows what else. There is a tristate (TRISD) for the data port (PORTD), but I can't switch it around fast enough to present the data to the Lynx. GRRRR. I have a timeout method for tri-stating the data port, but I'm unsure if I am messing up anything else in the system before it tri-states. GRRRRR. Oh well, what's a 20pin part amongst friends?

Update 13.0130:
Two things: a new Game Cartridge document and a schematic for a cartridge that will allow you to emulate whatever ROM you want, plus read ROM images from a USB thumb drive.

Note: The previous versions of the Game Cartridge document have been removed as they were flawed and presented incorrect information. There's enough bad information out there, I don't want to add to the confusion.

Also note: the ROM emulator hardware is not fully tested yet, not has all of the software been written. That will come in the future.

Here's the ROM emulator schematic V1.00 (5 pages):

And here's the new Game Cartridge document - V1.02 (10 pages):



Previous updates and the original post below the break.