Tensor 2011

From Artisan's Asylum

This is a list of ongoing Tensor-related notes, tasks, and projects.

Contents 1 More info 1.1 Loews boards 1.2 Etherner-DMX controller boards 1.3 DMX 2 Spares 3 Zapis 4 Specs 5 Suggested Mods 6 Protection 7 Playa infra 8 Code 9 Sexy 10 Lingering Questions 11 Issues

More info

Loews boards

Stock connectors on the rear of Loews boards were made by Switchcraft, have four pins: power and ground, RS-485 D+ and D- (data). Should be ok to do continuity tests from header pins to see which goes where. The connectors used for Tensor Loews boards was probably added because it was much cheaper than the Switchcraft connector and easier to make cables for. The original connectors can almost certainly still be used to operate a board or set its address.

Each Loews board has some stickers on it. One of them will have an 8-digit number which is the board's hardware address, this is used by a ZAPI to set the DMX address. Another sticker will have a placement code for the board. The first letter will likely be an L, O, E, W, or S, indicating what letter of the Loews sign the board was intended for, this is followed by a number indicating the place within the letter the board went, while the last letter will be an E or a W, indicating if the board was for the East or West facing side of the sign.

Fractional Loews boards (2, 2.5, 1, and 1.5 pixel units) were created for edge areas of the sign where the letters curved and such.

Tensor connectors on front of Loews boards are AMP MTA-100's. Power supply connectors on distribution boards are probably MTA-156 (also used on iColor Coves and other CK stuff). When ordering a connector, factors: MTA is the connector family, the number afterwards indicates the pitch. Connectors may be straight or right angle, Tensor uses straight. Ends that go onto wires (as opposed to being soldered onto boards or the like) will be color coded to indicate which wire gauge they are built to vampire tap on to, so buy new ones with the same color as existing ones if same wire gauge is to be used.

Loews boards have a conformal coating for weatherproofing. This needs to be scratched off to get solid contact with test probes if one is doing diagnostics.

Testing a Loews board: When power is applied, all LEDs should dimly light for a few moments. Many of the spares may be flaky, a row of LEDs won't light or somesuch.

Chips on a Loews board:

• U?: PIC. Probably write once. Some pins go straight to the headers, so these were probably burned on an assembly line.
• U3: EEPROM. Stores the address.
• U2: DMX or 485 transceiver, Linear Tech 490. Check pinout; it will probably have D+ and D- in, D+ and D- out, pwr, gnd, tx select, and enable. The D+ D- and GND traces on the header (input, lower) side of the chip seem to connect both to header pins and to the Switchcraft connector on back. On the output side they go to the PIC.
• U4: Voltage regulator, 5V for PIC

Other components:

• Big cap by headers connectors to power and ground, check polarity to help decode the pinout
• Y1: Crystal

Etherner-DMX controller boards

• Why six comm boards per panel when two would have sufficed to handle the required DMX address space of 180 3-color modules per panel? Speculation includes bandwidth or latency for DMX updates to the boards, some hardware limit of the Loews boards, or some software limit of the PIC firmware, which was adapted from existing code and not written from scratch specifically for Tensor.
  • Answer: Last option. an RS-485 run can have a max of 32 devices on it. Frostbyte made a board at CK that was designed to test a max of 32 devices; more would have required an RS-485 repeater/signal booster/transceiver. This board was adapted to make the Tensor controllers. The main mods were that it was shrunk as small as possible, and that the code was modded slightly because FB was concerned about directly running off copies of CK-owned code. Ten Loews boards is 30 pixels, each pixel is quite probably an RS-485 device.

Ethernet is 10 Mbit.

DMX

RS-485 chips have buffered outputs to attach directly to the bus.

The DMX-512 bitrate is about 250 Kbps. This is apparently rather slow for RS-485. There are two flavors of RS-485 transceiver chip, "slew rate limited" and non-limited. Don't mix them. If the signal level changes too rapidly, it makes noise on the line.

Spares

• Loews boards
  • ~12 triples at AA. untested, unconnectorized.
  •  ? triples in box from Carl. Untested, unconnectorized, Switchcraft connector on at least some of them has been mucked with (shell missing, pins bent)
  • 19 triples at Ct. 16 connectorized. Light coating of playa dust; perhaps brought out as spares? Also a number of 1.5's, doubles, and a single 2.5.
  • Joe from MakeIt offered AKB a pair of triples he got at Flea
  • There should also be a box of pristine from factory boards. Either Carl has them, or check with Ct.
• Comm boards
  • untested spares or spares in need of rework may be in storage
  • code might exist as hardcopy
  • code might exist on old hd's
  • sean suggested old PDS-150 boards could be adapted
  • reverse-engineer?
• power supplies
  • Have a pile of little 2A supplies from David Stokes.
  • buying a couple would be great. $$ required.

Zapis

• can Loews board addys be read back?
• can be emulated in software? Yes. A ZAPI send data using RS-485 signalling, no special voltages or pins. Just need to spy on one to see what it is saying.
• Version 1.0 ZAPIs can't program Loews boards, any newer ZAPI should be able to. Still unknown if a ZAPI can read the address off of a Loews board.
• The ideal way to set an address would be using a Color Kinetics MOPS or iMOPS power supply. These have RJ-45 jacks to attach to the ZAPI and terminals to send power and data, would need to make a cable from the terminals to the Loews board. So the ZAPI and the Loews board both get plugged into the MOPS. This protects the ZAPI and provides convenient power. The alternative is to make a Y-cable that takes D+ D- and GND from the ZAPI and PWR and GND from a 24V power supply and connect this to the Loews board.
• Three places to attach a ZAPI (or for that matter any old RS-485 DMX controller) to a Loews board: the Switchcraft, the header pins, or the extra connector added for Tensor use.
• ZAPIs have RJ-45 (well, technically modular 8-place) connectors. Uses four wires: D+ D- and two GNDs. Color Kinetics hardware usually only bothers to run one ground, though. There might be two for purposes of balancing the twisted pairs in CAT 5?

Specs

• Tubing is 1" x 1" o.d. aluminum, 1/16th" thick. Order double thick?
• bottom legs 48" long
• hypotenuse legs 96" long
• A Loews board is 1.5" deep from front of LEDs to back of Switchcraft connector shield

Suggested Mods

• add crossbraces to panels

Protection

• need display case for AA w/lexan?

Road case possible features:

• Can be used as a stand; would need a lip for the front edge, and holders for the legs.
  Might be nice if it was easy to pallet jack it while attached to a stand. But if stand runs 8 feet deep from front of panel, that'll tip back on the forks...
• Carry handles
• Can we get decent latches?
• Carry pole?
• Wheels?

Playa infra

• generator
• fuel
• transport. 1 truck share = ~$400 for 100 cu ft.
• better control PC

Code

• Original
• Josh' - make work at AA
• Ct
• Open API?

Sexy

• Swingset for Playa?
• bubble machine? how to protect panels from bubble juice? acrylic?
  • the panels are actually conformal coated and should (theoretically) be ok, the Playa however, will not be. No bubbles.
• wifi control station?

Lingering Questions

• Check the back of the Loews boards for numbers written on them. There may be DMX numbers. There also may be an IP address (or the last byte thereof) on the back of the Loews board closest to where each enet controller goes.
• Do the Realtek enet chips used on controller boards answer pings?
• We're not sure why a resistor was added as part of the Tensor Loews board mods; best guess is that it is a pull-up for something. Examine board?
• Check some Tensor Loews board caps against stock Loews boards to make sure caps weren't changed as part of mods
• What is the pinout of the switchcraft connectors?
• What is the pinout of the Tensor connectors?
• What is the pinout of the header connector? Check for pins strapped to ground or signal or voltage in area proximate to header.

Issues

• Josh' VJ code should be reconfigured to run on the panel at AA.
• Resolved Some of Asylum's power circuits have an issue relating to a 60V potential difference across two legs of the circuit (ground and neutral? hot and ground? not sure of further details) that causes one power supply to flake out; when using Tensor at Asylum, make sure it's a on a good circuit. The infrastructure crew has been informed and should be checking into the situation; it may be load related, and may have something to do with the side outlet runs at the Asylum having been pulled with only two wires. In October, the outlet by the welding area near the elephant mural worked, but when tried more recently, the lower left Tensor segment didn't work with that outlet.