This section will report the electronics I am interested. It will not include most computer things. |
See the Atari or MTG sections for that.
Christmas Trees:20feb2016. In getting several magazine subscriptions, as a common thread, there is the Xmas tree project in most Dec issues. Now, since they show up at the end of Nov, its usually too late to make the project for THIS year. And most of them do not provide a pcb image any longer. And others make finding the pcbs to buy difficult and/or expensive. So they have to engineered. With the schematics and pictures of the boards, some can be reverse engineered. I take an image and redo it in a object design program so I can get scalable lines and fills.
Things to remember are that boards are usually made for manufacture and are not usually good candidates for home etching as is. The traces & white isolation line need to be fattened, thru holes need to be bigger and sometimes moved from under other parts. Double sided boards can sometimes be made into single sided by adding jumpers. Make sure the image is sized properly and mirror prior to printing. One test I do is to verify the spacing of ICs and strip connectors is at 1/10th inch(multiple). Or use pin spacing of smd chips.
Over the years, I have collected the following:
Elektor(2012):Med, standup-using a pic chip. Uses 56 white Leds. Two of these can be connected together so the animations move between them. Once I finally found them, the boards were sold out. But they were also Expensive! A PDF of the boards is available.
NutsVolt(2014):Small, earrings/ornaments, smd using pic, thru-hole using color changing leds.
Poptonics(2001):Small, almost an ornament using a pic.
Popular Electonics(1995):Med, standup-using timer chips.
Popular Electonics(1994):Med, 3 wing standup-using hard-to-find LM3909 Led Flasher chips.
Popular Electonics(1993):Med, a collection of three electronic parts a ornaments. I've had mine out as wall art for many years. I am also adding a relay part to this.
Audio/Video Multiplexer(AV Mux):10feb2016. I have been working on this for a decade. It came from Circuit Cellar magazine. My problem was not having a useable parallel port(about 20 signals). So this was on the back burner. Then came along the RF mux from Radio Electronics that I wanted to add in, somehow. In the years since, I have redesigned my version. It now uses a single rs485 link to boards that are controlled with a simple ADAFRUIT Pro trinket 8 bit 16mHz processor. Reduces the overheard and complexity a lot, though I have to learn about pic type programming. Yes, I am using an 800XL to control this setup.
I will post pics as I progress.
But first, I needed a switch matrix to control things, at first. I could not find simple diode encoder circuit on the net, so I designed my own, in three tries.
Diode matrix schematic.
Then came the rack board with the monitor, switch board, 800XL, and power supply mounted.
Front A. - - - Interior A.
LED Head: 18Nov2007. Once of the electronics wall art/ornaments I have built from Electronics Now July 1994. The one thing I never liked is that it spends too much time frowning. How I resolved that and fixed errors in the schematic and pcb is Here.|
Visible Relay: I loved the Electronics Ornaments in the Dec 1993 Radio-Electronics magazine. I thought it could use a couple more in that line, so I have designed the first..an electronic visible RELAY. I hope to get this in Nuts and Volts magazine. An AVI(11 megs) of the Visible Ornaments I built here(Includes my LED Head) here, and AVI(9 megs) of my Visible Relay is here. The article has a confusing mix of using +5 and +12 volt supplies. I have only ever used +5(my relay only uses +5). I will have Relay boards and kits soon at MTG. The only link to Ornaments and Glitter Globe was at e-clec-tech.com, but they look to be gone.
2600 512-in-1 cart: My interest in atari lead me to find info and a pcb for a 2600 game console 512(programs) in 1 cart. But the pcb was in MS Visio format. What a pain to extract out. I had to go over and redo both sides to something I could make a circuit board from. Here is the resultant image PCB. BUT NOT THE ONE I ACTUALLY USED! I replaced the small adress hex switches with more robust versions. The main site is here. Pics of my version soon.
GAL BLASTER: My interests lead me to wanting to do some GAL burning. I didn't need an expensive burner handling 30000 numbers. Just a dozen common types. I finally found GAL BLASTER. But the image was a low rez. The eagle schematic had errors. The pcb image had parts on top of others. Sigh. Spent time cleaning it all up. The resultant images are here. The main site Here|
Oct07:Still working on this. There seemed to be some major errors in the schematic and pcb. Mostly works, but the programming voltage is always .02xx. Looks like the output of the d/a chip is tied to +5 volts instead of the op amp. Sigh. Don't like working on and fixing some one elses project. And apparently few have tried to make it.
(18nov07)Well, digging deeper shows the DAC can be connected in reverse to make it a voltage stepper. So the schematic and pcb are right. Fixed a trace(sigh) and now I get 9.5V at the the programming pin. Too low. But can't read a gal. Looks like data pin 1 has a fault.
Fixed that I think. Only problem is the programming voltage never gets above 9.5. Sigh. Can't tell if I am actually reading gal data even. What does a blank gal look like?
(2011)I have redone this schematic without the voltage stepper, etc. Instead, I am making a target board for the gal I want, and it programs the variable voltge out with a resistor. Will find the time to make one day.
Schematic and PCB designer software.|
For the longest time I did all of the design by hand. Having software on the PC greatly eases the design phase, particularly as my stuff gets more complex. There are 2 programs that are mostly used to do this EAGLE and EXPRESSPCB. Both have free versions.
EXPRESSPCB is the software I use. I think its free only. And a little more user unfriendly. There are two programs, the schematic designer where you draw the schematic first using logic parts. And the PCB designer where you literally have to redraw the entire schematic over again using physical parts. You place the parts where you want them. Then you run wire traces(set to .03 inch or so) to every pin you used in the schematic. While an autorouter would be nice, it has a great feature where it can highlight all of the pads that are connected together in a netlist from the schematic. Its very easy to create custom parts. Almost all I use I have created because I want parts with pads big enough for homebrew making and user soldering. It is easy to create pcbs larger than 6 x 6 inches, the average size for hobbyists that have to use through hole parts. Schematics can cover several sheets, one sheet does not hold much. I would like a few features in the software: align parts/even spacing, group change of traces or pin pads, free rotate of parts. Creating a prototype pcb involves displaying top and bottom layers, getting a screen cap, loading into an object editing program, and recreating the pads and traces again. Adding in alignment triangles so the two sides align. Then print and edit till its right.
I have now done three orders for circuit boards with them and I rate them A++!. Software is now XP and higher. I rate the software a B+. If they had a $49 enhanced version, I'd buy it. Note that there have been no major enhancements in too many years. It needs fully rotatable parts urgently. It is a PITA to have to create a new part for each angle. You can't even create a clock face with LEDs around the perimeter without juggling the pads! I am looking into alternative programs.
Eagle has several paid versions as well. This was the first software I played with. It looks to be a bit better in that it has an autorouter for the pcb traces. Part creation in the light version wasn't available, but now is. However, I can't give this one high marks for the hobbyist/minimal user due to several limitaions. Mostly, the largest pcb you can create is about 2 x 3.5 inches. Fine if you are using .5mm pin pitch smd parts, but not for through hole-its only big enough for a couple of chips. And only one schematic sheet. Fine for the tiny board, but nothing else. If you use this freebie for anything commercial, you have to pay a $49 registration fee. Which gets you nothing. No bigger board. To get that will cost you between $400 and $600. Far too expensive for the hobbyist plus. I don't think I could ever sell enough boards to pay for this. The $49.00 version should get an enhanced hobbyist+ version. The stuff I did in Eagle I have now redone in EXPRESSPCB. I only use this software to export/print stuff done by others. I then recreate it in EXPRESSPCB. They have versions for major OSes. I rate the software a D.
PCBPOOL is a pcb service I have not even looked at. They are based in Ireland.