Finally, an update

Well, I went almost the whole semester without even touching this thing. Now, I'm finished for the year, and I can get back to it.

I've finished all the display units. Each contains the LED, capacitor and resistor. I didnt put the diodes on these units since its difficult to solder them on (the wire on the diodes is much thicker than that on the capacitor/LED/resistor). Instead, I'll solder the diodes onto the other end of the wires and slot them into the breadboard.

I'm going to attach the display LEDs to the wire now, updates/photos will come soon.

Starting on the display module

I've started on the display, I've got 3 LEDs prepared so far. Each LED has a resistor and capacitor, but no diode yet. I've decided to put the diodes on the other end of the data cable, since soldering them to the monstrosities I've created is difficult, and becase diode wires will be easier to insert into a breadboard than the IDC wires. I'm considering splitting the data cable into 3 separate pieces, to make it easier to connect them to the shift regs. I'll post photos of the display units soonish.

Main circuitry is done

Heres the finished circuit (sorry for blurriness). I'm only using the board on the left for power (later on I'll attach a molex connector and use the 5V supply from that). The 4 rightmost LEDs in my temporary display are from the set I bought. Theyre much brighter than the LEDs I have been using, probably because they dont have a diffused lens. They have a narrower viewing angle however, and arent quite so bright side-on. They will look nice when mounted in the drive. Now I have to find my soldering iron and prepare the display unit. Until then, this will look cool on my desk :)

Prototype 2, now with more LEDs

I've connected the second shift register, and its working. The effect now works on 8 LEDs. I had to take out the capacitors to save space on the display board, but they will be used in the final product. The board on the left is the one from uni, you can ignore that (I'm jut using the oscillator and power supply from it). I'm starting to worry about the fanout of the 4013, the data sheet I found said it can drive up to 2 74LS chips... I've got 3 74HC chips, I'm not sure if that will be a problem. We'll see when I connect the next register I guess.

First prototype

Woohoo! I've got the eye working using 1 shift register. In the photo, the signal is traveling to the right, you can see the LED on the right is fully on and the one to the left is fading. When the signal reaches the rightmost LED, it starts traveling left, and vice versa. I've got it running off a 1hz oscillator I made at uni, but theres a 555 on the main board and I'll use that to make the 5hz oscillator later. 5hz will look cooler, but wont be any good for testing. Soon I'll expand the circuit to another register, I've confirmed the fade effect works so I'll take the caps out (so I can squeeze 12 leds onto that small board).

I havent started putting the circuit together yet... but I took a photo of all the stuff I bought, just to give you an idea of whats involved. Note the ribbon cable I'm using for the display is 16 way IDC, not only will it look suitable inside a computer, tests show that despite being multi-cored it slots into a breadboard fairly well. It was also the cheapest ribbon cable they had.

I will put together the cylon eye circuit tomorrow, or at least, as much of it as I can.

Ownage, of electronic parts

I've bought all the parts I'll need. I was able to find a 74194 supplier, apparently I was the first person theyd ever sold that chip to (I had no idea it was that rare). They were only $1 each, so I still come under budget. Now I can start work on the logic board, and that means photos for you soon.

Mounting box

I cant use the floppy drive to mount the circuitry. The structure of the drive wont accomodate a breadboard, and the screws are too worn to remove the drive mechanics. So, I've taken apart an old CD-ROM drive. It's contained within a metal box, which is just right for my project. I've taken the drive itself out of the box. The box is great, its the exact right size, the top cover is attached with screws (so its easy to remove). The only problem is the front panel of the floppy drive is slightly too wide for the box. This shouldnt be too much of a problem, if I cant find someone with a sander I'll just figure out a way to glue it on regardless.

Tomorrow I'll go out and get parts, and for the next couple of days after that I'll be putting the display unit and logic board together. Photos will come when theres something to take photos of.

Demo gif

Heres a demo of what the final effect should look like. Thanks to Imageshack for hosting (because Blogger cant host animated gifs).

Someone suggested I use the 7495 instead of 74194. This chip would work, however, I cant find anywhere that sells this chip either. At least this means I'll have a backup option if I cant find a 74194.

I've prepared a price list of the parts I'll need (except the shift register chips):
50xLED $9.98
50xDiode $2.25
breadboard $11.84
25xCapacitor 470u 10V $6.25
12xResistor 470R $0.48
1x555 timer $0.98
1x4013 flipflop $0.80
2xResistor 8.2k $0.08
1xCapacitor 10u $0.20
1xgreen Capacitor 10n $0.18
1xribbon cable 16way $2.89 (for connecting display to logic)
1xhookup wire pack $2.55

Total AUD$38.48

I'm buying way more LEDs, diodes and capacitors than I need to, in case I screw up some of the display parts, and also because I'll probably use them in future projects, and I save money overall this way. I'll be building the main circuitry on a breadboard, since I dont have equipment to etch PCBs, and also because this allows me to change the circuitry in the future. As long as the shift registers arent *too* expensive, the entire project should cost less than $50, which is about what I expected.