blog.jmp.no

Electronics, coding and hacking. And ADD.

MF2015: Stacker clone

2015
2
July

Since nobody's asking, I'll tell you myself: these days I'm building my entry for this year's Trondheim Maker Faire: a just, purely skill based version of the game called Stacker.

Technically speaking it's not very challenging. Instead, I'm aiming for an entertaining contribution to this years faire, it will be on free play, and will reward those go make it to the top by dispensing a candy. Oh, and I must stress that it will be fair - unlike the original, this game won't cheat.

Here's what sparked the idea, a gutted Indiana Jones slot machine that I got my hands on. The 100mm yellow pushbutton was the first part to arrive, and was included in this photo so that "you can picture the rest." ... Well, can you?


I decided to use one big display instead of breaking it into two parts, as the original Indiana Jones game did. My godsend friend Tom Erik volunteered to do the woodwork for me, and he quickly fixed the 7x15 matrix I needed to house the LEDs. I could have opted to use the entire width of the display, and may change this one day.


When the backplate arrived it was time to start the tedious task soldering some of the 200 10mm diffused LEDs I bought off ebay. This may look like a two hour job, but due to my bad back I had to spread it out over a period of three days.


Remember what I said about changing the display? Yeah... no. Not happening.

Anyway, fast forward, and the display is programmed. I used an Arduino for the task, since I'm lazy and didn't bother building a custom board for this job.

Here's the display scrolling some text for testing. I experimented with some additional diffusing by applying a sheet of sandwich paper. It's just to give an idea of what it will look like with a properly frosted glass plate.


The gameplay is nearly finished, and I will post another update once the display is mounted.


Dead basket arcade reborn with Arduino

2015
4
June

Here's just a quick update on one of the projects I'm involved with these days. What you see below is an Grayhound Championship Basketball, an arcade game owned by a friend. The original hardware was a Z80 system, but this is now being replaced with an Arduino Uno.

The current version only supports 1 player mode, but a variety of 2 player modes will be implemented soon.


The arcade to the left contains the original hardware and is working just fine.


The original power supply conveniently provides 0/5/12V, as well as a 110V for the solenoid releasing the basketballs to the player.

The Arduino is equipped with a prototyping shield where we soldered the connector for the back panel and the various buttons in use. A proper, more professionally looking shield will be designed at a later point.


Arduino General Purpose Floppy Driver

2015
28
May

There's something about old hardware that fascinates me, and I have an urge to incorporate this into modern hardware somehow. This is basically what I keep telling myself for creating this project on Hackaday.io.



As stated on the project page, the goal is to provide read/write access to floppy drives from the Arduino. Sure you have flash memory, EPROMs and SD cards, but nothing really compares to the comforting hum from a mechanical floppy drive.

And, hey, it can probably be used to play music on the floppy drive as well.


Amiga 500 rescue: well that was easy

2015
14
May

After replacing a few suspiciously looking capacitors, I decided to try replacing a few more chips again. Turns out one of the CIA chips I was testing with was also faulty. The Amiga 500 is back in business, running kickstart 1.3 and has a GVP harddrive on the bench as well as a Gotek floppy emulator installed.


Pardon the mess



Next modification is an ATX connector for the power supply, as well as a new HD for the GVP drive. The one installed is a whimpy 80 megabytes (!) and sounds like an idling jet carrier. It's too noisy, not even worth the extra 8MB of memory it provides.

The Gotek emulator is an interesting story, too. Back when I bought the drive, for reasons unknown, I decided to go for the lowest spec model possible. No fancy features, no 7-segment LED displays, no pushbuttons. Turns out, these features are very nice to have when emulating more than just one floppy image. So, I've started to upgrade the drive by adding a missing capacitor, an extra indicator LED and two pushbuttons. As soon as I find a couple of 74ls164's I will add the image number displays as well.


Amiga 500 rescue

2015
11
May

I dug through the pile of old computer stuff and stumbled across my old Amiga 500, which I bought for a fortune back when I was 15. This computer stuck with me through sickness and health and survived countless number of copyparties. It also took a fair amount of beating when the code I worked on crashed and I didn't have a single backup.

It was a huge disappointment to see that time had not been gentle with this little guy. I decided to strip it down to the bare minimals and start debugging.

The three burnt out resistors at E502, E503 and R408 have been like this for ages and is not the cause of death.

An ATX bench supply now provides a stable -12/0/5/12 volts, but the video output is just pitch black, although the VSYNC and HSYNC signals are generated. I've tried replacing the CPU, Kickstart ROM, PAULA, GARY, AGNUS, DENISE, CIA1 and CIA2 but to no avail. Looks like this may be an electrical error, so I'll fire up the scope and start working on it.

I'll keep you posted on the progress. It shall live to see the light of day again!


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