Hi all,
I am working on making a midi drum trigger with atleast 20 inputs. It is becoming difficult to wire all of these without an enclosure for the 1/8" jacks to be mounted.
For a project box I was thinking about using an old paper shredder. It can be opened up easily if I need to make adjustments to the circuit. Will the plastic housing of this box work fine for my application? Since it is plastic the jacks won't be grounded so I'm not sure if this will introduce hum into the project.
Anyone have any experience with this or any better ideas?
I'm going through this right now, though I need 2.5mm connections instead of 3.5mm (1/8"). What you want to get is stereo or mono panel mount jacks. These come with a screw cover that you measure the screw underneath the cover, and then drill a hole in your enclosure to match the screw. Put the screw through the hole, and then screw on the cover on the other side. You then solder wires to each of the three (or two) connections on the other side, and connect them as needed.
If you need more than a couple, it may make sense to order them from an electronics supplier, where the per unit cost is less, but you have to deal with shipping costs and minimum orders. You might buy one or two immediately to see if it is what you want, and then order the rest. For example: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_101143_-1.
A simple enclosure might be an appropriate sized plastic container you can get at the grocery store for lunches. You want something that you can easily drill through, but is strong enough for repeated attachments. You could use a cardboard box initially, though I suspect you may want to move up to plywood, plastic, or MDF, probably 1/8" thick.
Kerl, for shielding you could just use tin-foil. Not the toughest stuff. You could also get some spray adhesive and bond the tin foil to kraft paper (basically paper bag material) or card stock.
And of course, there is aluminum tape used for flashing at the hardware store.Just line whatever face you will be mounting your jacks.
This way you can use plastic (or anything really.) My father used to smoke cigars, so I collected all the cigar boxes from him over the years to use for storing small parts and for encolsures.
If you do use a plastic food container, make sure it is not a cheap one, because the plastic gets brittle over time and will crack and fall apart.
It sounds like retroplayer was starting from the enclosure side, and I was starting from hooking up 20 1/8" (3.5mm) phono adapters. However, as I read it again, you don't really need 20 inputs with 1/8" plugs, each of which contains two wires for a digital sensor, or three wires for an analog sensor.
One thing you can do to organize the wiring it to ethernet cables to connect multiple signals together. Ethernet cables contain 8 wires, so typically you would be able to attach 6 sensors, a ground, and a power wire to each cable. Adafruit sells a nice little patch shield that fits on an Uno (or other microprocessors with the same shield layout) that provides 4 plugs to plug in ethernet cables, and then 4 connectors on the other end to distribute the wires to a breadboard or protoboard: Patch shield for Arduino [v5.01] : ID 256 : $19.50 : Adafruit Industries, Unique & fun DIY electronics and kits.
A different way to wire things up if you don't want to go down the enclosure route, is getting one of the various sensor shields out there. These shields break out each Arduino Uno pin into a set of 3 pins (ground, data, power), that you can then connect each sensor easily. Note, some sensor shields have a different ordering for the digital pins and the analog pins, so be sure you know how yours is wired up. Here is one for the Uno: http://yourduino.com/sunshop2/index.php?l=product_detail&p=2 and one for the Mega: http://yourduino.com/sunshop2/index.php?l=product_detail&p=195
Thanks everyone for the advice, wow I had no idea you could use an Ethernet cable for any kind of wiring you wanted.
But yes I already have the 3.5mm panel mount jacks I just need some way to organize them so they aren't flopping around my desk anymore
I bought a large cardboard cookie box (like a circular cookie tin shape) so I hope that will hold up. I will try the tin foil as a grounding material. I tried this before when I was making guitar effects pedals but the foil ended up shorting out some components so I'll be careful with that now
In terms of grounding material, I would suspect using a breadboard with the red/blue power pins down the side inside the enclosure would work, since it is already has the wiring set up for 20 or more pins (if you use the power rails). Or if you don't have an appropriate sized breadboard, Radio Shack does sell a Schmartboard that is made for just power and ground distribution: http://www.radioshack.com/product/index.jsp?productId=12825865
The alternative as I said is get a sensor shield which has individual power, ground, and data pins for each Arduino pin, and connect each 3.5mm panel mount connector to those pins. You can buy servo connector wires that have a 3 female connector for the sensor shields fairly cheaply, and you would cut it in half using each half to attach to the sensor shield, and the other half to solder to the panel mount connectors.
Michael, ok thanks for the advice! I guess I should have assumed that using the arduinos ground would be enough since most projects aren't additionally grounded to anything else. I have 2 large breadboards so I think I will have enough room to ground everything to the ground bus.
One problem you may encounter is that 3.5mm panel mounting jack sockets are typically designed to be attached to thin sheet metal. You may find that plywood, or the lid or side of a plastic box, is just too thick for them.