My home built metal DDR pad (Part IV)

[Matrlx]

Hi, I've been following this thread for a while and I've sort of had a pad under construction for the longest time as well.

I did a lot of research between the 3 pads (DDRHomepad/Riptide/Stoli) and tried to come up with something more to suit what I was looking for in the pads. The result was that the base of my pad ended up something like a cross between Stoli's and Riptide's. It has a height of 2 inches with a 1 inch high bay under each arrow for lighting support if desired, constructed from 4 layers of 1/2 inch plywood. It also copied the dimensions of the actual arcade pads including the side, front, and back borders for functional purposes (safety+side by side pads for doubles).

As for the sensors, I actually went through both the DDRHomepad and Riptide designs while building the pad, and found the Riptide design (With all the screws wired to the common and the top plate wired to the signal instead) worked a lot better due to the fact that I was using 2 layers of 1/4 inch plexiglass for each of my arrows (no flex allowed), although I kept the bracket setup as in the DDRHomepad design. But I still had a decent share of problems with it.

I might've been using crappy weatherstripping or something, but the stripping would 'break in' and lose some of it's strength through frequent play, and eventually the arrows wouldn't stay off the screws so I'd have to adjust the screws. I also had to adjust the screws simply because stepping on the screws hard enough could affect their positioning. I guess I might've been using crappy adhesive too or something, but the metal on the bottom of my panels came loose eventually and caused the arrows to be stuck as well.

I set out to find a way to change my sensor setup so I wouldn't have to worry about these things anymore, and I think after a few months of procrastination I've cobbled up the solution I've been wanting.

It's pretty simple, but I think it has a lot of advantages:
-Removes the need for the metal sheet under the arrow panels
-Removes the need for weatherstripping
-High reliability and sensitivity



It's basically 2 mending brackets, with one being connected to common and the other to the signal. I've found that certain mousepad materials are much more 'durable' than weatherstripping in addition to being stronger. Depending on how high your mousepad is, you can experiment a little to find a certain washer(s)+screw combination that will leave the seperation between the top mending bracket and the screw very very small. The sensitivity can also be adjusted by the amount of mousepad you fit inbetween the mending brackets.

I'm planning on placing 4 of these on each side of the arrow, much akin to how the arcade sensors are set up. Then all I'll have to do is place the arrow panels on top, and I should be all set.

This is the diagram I made when initially planning how my pad was going to go together in the end. I added the mending bracket setup to show where they would go. Left side is the top of the pad with the arrow panels removed, the right side is the layer that the stationary panels will sit on top of.



(Don't ask about the buttons up top there, I'm still trying to figure that out...)

[HitokiriX]

Klaiviel tell me how those microswitches turn out. I was wondering though...if the sensors are used for keyboards won't the sensors be really small? I'm guessing you'd need about 3 sensors per side per arrow. 12 sensors per arrow, 48 for 4 arrows, and 72 for 6 arrows. In the end that adds up....

Matrix that sounds like a really good design? I might try it in my own pad. Should be quite reliable and sensitive from the drawing you made of it. You know what I think I will try it. My pad'll probably be done round end-February Mid-March, so it might take a while to get back to everyone on how the design works in reality, but my expectations for this one are pretty high!

[HitokiriX]

I found that mending brackets are around 1/8 of an inch thick. So for that contact design having a mending bracket as a base AND top contact will probably make it too thick to fit under two 1/4" plexi panels and fit a mousepad in between as well. Maybe if you didn't include a base at all and just pinched the wire betewen the washer and screw, and kept the mending bracket as the top contact it would work.

[marcan]

Hi all! For those who don't remember me, I that guy who was trying to make an analog-sensor adustable sensitivity PS2/XBOX/PC compatible lighted DDR pad (there you go, a one line description )

Here's how things are turning out. First, the pad. I've made my own design borrowing ideas from the others. Once I have everything done I'll document it fully. It is basically just wood panels on pegboard, and two pieces of lexan on a wooden support on the pegboard for the arrows. Weatherstripping provides cushioning and the sensor rests directly underneath the arrow, supported by a wood octagon.

Now for the good part. I've been messing around with the new PIC18F4550 microchip since christmas. Here's the status:

- Pressure sensors work. Threshold is adjustable. It also has adjustable hysteresis to prevent "vibration" of the outputs (rapidly turning on and off while close to the threshold). Semi-automatic calibration of the sensors.

- Lights work. Not much to say here. I haven't added anything nifty yet, since I want to get everything working before I add all the details.

- LCD screen. The pad has a 20 character by 4 line display to configure it, etc. It is very useful during calibration and to configure everything and show the pad status (plus I made a nifty intro for it, and I'm thinking of fun stuff to do with it if I have extra program space). It currently tells you mode of operation (USB/XBOX/PS2), status (IDLE,RUNNING,etc), light status (active,off, controlled by PC), threshold for pressure in %, and the current pressure for all the pads as little circles that gradually fill in depending on pressure.

- PS2 interface is not done, although it is very easy to get going. It was already working on the previous 16F876-based version, so it should be very simple to port.

- USB interface. This is what I've spent most of my time on (darn USB is VERY complicated). PC mode works, the pad shows up as a regular USB gamepad. No drivers needed. Tested on Linux and Windows XP.

- XBOX (USB-XBOX) mode. This isn't working with the xbox itself, but works with the xbox pad drivers on PCs (both win and lin), and interestingly works on the menu of my xbox modchip. I need to figure out what is happening here. It seems the xbox doesn't read the pad. It might be another issue with the USB hub that the XBOX requires. I'm looking into this right now.

Right now, I can play Stepmania with it on the PC. Soon the PS2 part will work, and hopefully I will be able to figure out the XBOX problem. The circuit is relatively simple for the functions that it includes, since the microcontroller does most stuff. Components include the microcontroller, some resistors and capacitors, 4 power MOSFETs for the lighting control, some potentiometers for adjusting the inputs, a transistor, and little else. The sensor pre-amplifiers are located inside the center square of the pad (to minimize distance to the sensors) and are fed with twisted cable to minimize interference. They consist of a dual opamp and some resistors, per pad (4 total).


The pad. The left arrow sensor block in the picture (top actually on the pad) is upside-down, revealing the metal sensor (the actual sensing element is bonded to the metal on the other side, resting on an indent on the wood). The bottom (left) sensor is placed the same way it will be with the pad put together. This arrow position is currently missing the supports for the lexan (look at the others). On the right (bottom), you can see a lexan panel on top of the sensor. Screws not installed yet. I'm using stoli's idea of the rubber tubing. Do note, however, that the idea is for the lexan to move very little. It should rest on the sensor and apply pressure to it without moving much (it will bend unless you are dead-on center, but that doesn't matter).

Also note that the sensor cables disappear in the center square, and new ones appear on the left. The amplifiers for the sensors are underneath the center square (they are two small and thin boards that fit with plenty of space in the area between the supports for the wood).



Side view of the pad. You can see the supports for the wood.


The circuit board. Note the big microcontroller in the center. A test LED light is installed at the left (these will go inside the pad once done). You can see the USB connector at the right. The pin strip cables/connectors are (left to right, up to down): power (for amplifiers and microcontroller programmer), sensors (output from amplifiers), reset jumper (almost hidden above the chip), programming connector (not needed once finished), LCD connector (middle 4 pins not used since I use 4-bit mode), (left side again) lights connector, configuration button connector, PS2 controller bus (left of LCD connector), select/start/etc button connector (underneath PS2 connector), external power connector (optional) (next to it).

You can see two jumpers that select where the power comes from (PS2 interface, USB interface, external power).


LCD screen. It shows USB state (IDLE, ie no program is reading the pad), sensitivity (64%), light status (light bulb symbol, ignore the "00" since that is only there for debugging), mode (XBOX), and the pressure to the pads (note the semi-filled bottom circle, since I'm applying pressure to that pad.

[HitokiriX]

All that tech you have in your pad seems cool and all, but I'm worried that the build of the pad itself isn't study enough to play on anything but hard wood. It looks like your base and stationary panels are each 1/4" with 1/2" supports in between? Seems a little weak to me, but I hope it proves me wrong!

[marcan]

The base itself won't break as long as it is placed on a reasonably flat surface. The wood is supported by a different amount of supports according to (predicted) stress. For example the center panel has plenty of suport, on all sides and 3 bars across the center. The corners have the most support in the sides that touch the arrows, as you can see on the right side of the picture.

I've stomped on it. It won't break (I hope). My main goal building this pad was for it to be a simple design, and lightweight.

[Matrlx]

[HitokiriX]

1 inch? We're using different designs then. Anyway I'll have to create my own version of your contact to fit my own pad design.

I'm really not cool with the corner brackets in Riptide's pad costing so much at home depot. They don't carry any in bulk or any other brands. A real rip off. Has anyone seen corner brackets in any store they've gone to costing less than 3$ each? If so I'd be willing to send some money to you to pay for them including some shipping money.....

[TheMonster]

[HitokiriX]

Hey did anyone ever verify if spray adhesive makes a crackly noise when stepped on? Like stepping on the stationary panels when the sheet metal is glued to the wood panel using spray adhesive?

The mending braces are just glued onto the mousepad bits with elmer's or something. Nothing heavy duty, TheMonster.

[Matrlx]

The brackets stay on top of the mousepad, they could probably just rest there, but any sort of adhesive would be safer.

The mousepad I'm using has good grip on either side so it doesn't slide when pressed against the mending brackets, and I'm just using a couple short strips of scotch tape wrapped around the sensor to keep it from falling apart when I'm handling it.

I have a question myself though, how rigid is Lexan? I've been under the impression that the metal on the bottom of the panels help make it more rigid, but I'm curious how much Lexan will actually flex when stepped on. If it's rigid enough, I'd consider taking to it and be able to reduce the height of my pad by half an inch, which would be nice.

[nico_ddr]

I have a question : I built a pad and it worked really great until today. I don't know why, but today it stopped working. I looked at the pad connections with an ohm meter and the electricity still passes through the wires, but when I want to play, the pad won't even respond...



Yesterday, I could AA easily anything with it and today it's not doing ANYTHING

Any help ?
_________________

[geckoinc99]

Nico_ddr,
You might want to check the circuit board itself. If it just suddenly went dead and your connections seem okay, it could me that your board was hit with static electricity. That's about the only thing I can think of anyway.

Marcan,
That is a wicked design. What type of sensors are those? I know what you mean by USB being complicated. Good luck with the design. Something I thought about with the tubing idea. I don't remember the details, so if this was already suggested, just ignore me. I though that you could strengthen the tubing by filling it with silicone sealant. It would remain flexible, but give better resistance. It's just a thought.

HitokiriX,
On my second pad I used the 3M Super 77 spray. My impressions of it was that it goes on very nicely (smooth and even), and initially stuck well, but as I wrapped the metal around it popped on the surface. I even had a board clamped on the surface as I wrapped. It just doesn't have a lot of holding power. Now those spots make some noise (some louder than others). The best stuff I've found so far is standard contact cement. It takes two coats, but it holds like nothing else and you don't get cracking sounds. The drawback is that it's hard to go on smoothly and even, so it can show up on the surface after wrapping (that depends on the thickness of the sheetmetal though. I use thin aluminum flashing). Just my information for you.

David
_________________

Life is very different 3000 feet above the earth with only a wing to hold you up....
Can't wait to be there again. Wanna join me? Visit http://www.hanglide.com

[geckoinc99]

Okay everyone,
First of all, I apologize that this took so long. Life decided to be complicated, plus I don't have a real digital camera (just a web cam). Anyway, I got a simple web page made to outline my portable pad design. If you have questions about it, just post a reply or send me a PM. Hope you enjoy!

http://www.geocities.com/geckoinc99/ddrpad.htm

David
_________________

Life is very different 3000 feet above the earth with only a wing to hold you up....
Can't wait to be there again. Wanna join me? Visit http://www.hanglide.com

[marcan]

[aluminum.]

Yes these look hella good but your website does not give that much detail, so I coudn't build these.

[HitokiriX]

[geckoinc99]

If you're referring my pad, I said I didn't have time to write up a formal thing, though it's mostly a Riptide pad with a small modification to the arrow pads. If you're interested in it, I can write up directions on them. Just let me know.

David
_________________

Life is very different 3000 feet above the earth with only a wing to hold you up....
Can't wait to be there again. Wanna join me? Visit http://www.hanglide.com

[smileboot]

I made my own post about this but id thought id ask here.

Does anyone have the schematics/plans for the arcade ddr pad as i plan to make my own using replacement switchs and such (only $10 a switch and only need 2 per button) but im a bit lost on the internals of the pad (placing of switchs and such). So any help would be much appreciated

[HitokiriX]