blog.jmp.no

Electronics, coding and hacking. And ADD.

Let's play Де́нди!

2015
19
December

On my desk today is a game console from the 90's called Dendy (Де́нди), and as the cyrillic implies, it was aimed for the Russian market. A friend of mine recently got his hands on this console, but since it did not appear to work I was asked to have a look at it.


It's like the design is from a Star Wars movie

Opening the case was no big deal. 6 Phillips screws later the case was open and the main PCB was exposed. I did some work on an original NES a couple of weeks earlier, and was expecting something a bit more... uh, "more" than this.


Take me to your leader

At first I thought this was the interface board, and that a smaller, more populated board wold be underneath. But no, this was it: a single-sided PCB with a penny pinching sprinkle of passives. Worth noting is the center-negative 9V power input, which is regulated down to 5V via the linear 7805.


When I saw the bottom of the board, I had one of those "a-ha" moments that you read about on blogs. So, "a-ha". This is a NOAC (NES On A Chip) clone system. The UM6561F-2 does all the magic involving CPU, GPU, audio and I/O.

What's interesting on the mechanical topic, is the cartridge ejector. Just like the one on the Famicom consoles, except it doesn't work. Here you see the plastic construction consisting of two two wedge shaped ejectors that are supposedly there to eject the cartridge, however this construction is so weak that I hesitated using force on it.


Here's how it works from the cartridge view. If you try this with a cartridge the ejector will probably break.


Anyway, back to the repair job. It was in fact dead simple, and only a matter of a dodgy barrel connector. A replacement was donated from a dead Arduino. I applied a generous amount of solder to make sure it stays in place. However, I would consider hacking it to be center-positive, since this is more or less the standard and opens for a wider range of power supplies.


I was tempted to dump the cartridges, and opened one for inspection. Turns out they are budget chip-on-boards and not 27-series EPROMs as I was hoping for. Dumping them is not impossible, but I requires a bit more effort.


One last thing, though, and that's the neat joystick slots on the side of the case. These are nice.


Oh, and animated GIFs instead of Youtube videos - yay or nay?


Trondheim Makerfaire 2015

2015
31
August

This weekend I attended Trondheim Makerfaire 2015, along with a few other members from Hackheim. Despite the bad weather, we had a blast meeting all the visitors and each other. I should also stress that this was a wet event. The rain was pretty rough Thursday night while we were rigging up the gear, we had a little river running through our tent to the drain. And when I say river I mean a pretty decent one; a fellow hacker actually built a model boat that sailed through it.

Let's take a quick walk through the 'faire and let's see what we have here.

This is Hackheim's fruit-o-phone (mainly banana-and-melon-o-phone), based on the Makey makey:


Just behind the fruit-o-phone was Timeexpander's bench, featuring the Götterdämmerung (I and II) 3D-printers, as well as the intriguing Citybeest:


Here's Hans Jørgen Grimstad, the creator of the Citybeest, showing his robot in action on the pavement:


The augmented sandbox was a great success last year. It's running Linux and gets its 3D vision from an XBox 360 Kinect:


The Stacker clone I was working on was done in time, too. I have no idea how many games were played, but it was in the hundreds. Not many made it to the top, though.


The latest revision of the C64FC was also shown. Quite a few recognized the computer from their childhood, and a lot of kids even took the time to play some old classic games. I had to cover the C64 in cling foil to protect it from the rain.


Some commercial and a couple of homebrew quadracopters were also on display. I did not know those small buggers could do loops, but I do now.


This was ARM's tent. Unfortunately I didn't get a good picture from inside due to the crowd, but they demonstrated their Mali graphics chip, in both mobile and embedded platforms. They even gave away a few arcades to some lucky contestants.


Awesome metal sculpts from Scvulp. Yes please.


As the sign says, it's a "Post apocalyptic supermarket." featuring fancy items such as zombie survival kits.


A motorized monowheel by Smørekoppen.


Revolve's electric racing car. This thing moves.


If you don't fancy electric motors, try this twin turbo based turbine beast for change. Here's a 6-second clip of it idling (RIP in peace, headphone users)


..and if you don't like driving, then how about flying? These eight hexacopters can, with a small dose of added bravery, lift an adult person.


And that's about all the pictures I had from this years Makerfaire!

I'm already making plans for next year. It will definitely be something waterproof.


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.


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