Wiring Team

Wiring Team

DIGF-2005-001

January 25, 2018

 

Wiring

 

Process:

 

https://docs.google.com/presentation/d/1Rf3LAA2yxtv8NxzLapPuzdjaUsADUxSeE42De0c6RFM/edit#slide=id.g2edd56b021_0_44

 

Things to look in to:

  1. Communicating between boards
  2. Multiple nanos and multiple screens
  3. Connecting the uno with sensors
  4. Photoresistor, potentiometer, pressure sensor (just one of each)
  5. Communication of sensor nano to all other nanos
  6. Redundancy
  7. Labelling system
    1. On screens
    2. On Nanos
    3. On wires
    4. Everything
  8. Troubleshooting system

Materials Needed:

  • Wires
  • Photoresistor (1)
  • Potentiometer (1)
  • Pressure sensor (1)
  • Protoboard (1)
  • Headers (60)
  • Breadboard (1)

 

What if we used the PWM pins for float and int information (photoresistor, potentiometer, pressure sensor) and Digital out pins for boolean information (such is on, thus is not)

 

Wiring Legend

COLOUR PURPOSE / LABEL PIN
Red Power 5v
Black Ground GND
Yellow SDA (OLED) A4
Green SCI (OLED) A5
Orange I2C (Nano to Nano) ( RX + TX, MAYBE! )

 

Final Documentation:

 

Initial wiring test:

One of the first steps was to start soldering power headers into protoboards, allowing for the large amount of connections that would be needed. We left a few extra pins, partly for inter-board connections, and partly in case of faulty connections (this came in handy).

At first, we planned to power the OLEDs using the 5V and GND pins on the Arduinos. This was scrapped in favour of keeping separate power headers on the protoboards, making for denser boards, but sturdier connections.

On the initial test day after these three separate protoboards were put together we tested each OLED screen and arduino to make sure that they were functioning properly, and that the connections from the boards were correct. There was one faulty protoboard which meant having to fix the short so that the connections were no longer bridged.

It was also at this time that we added a third header to transfer state information from the central Arduino in the control panel.

Everyone was sent home with an individual screen and nano so they final wiring job besides the protoboard power connections couldn’t be started until the morning of, which was the real challenge.

 

Wiring to the Domes

Labour for dome-wiring was divided in two sections. One team dealt with the base, and the other simultaneously dealt with the internals of each dome.

We started by drilling an extra hole in the case for the 5V power cable.

The first problem that came up when attempting to wire the Nanos to the OLEDS in each dome, was figuring out the organization of the wires. We only had to colours (red and black) to work with, and this immediately led to some confusion to where everything belonged and connected. We used black-red-black-red as a mnemonic for the OLED wiring pattern. In some instances, this pattern was reversed, leading to a substantial number of burnt-out screens.

The wires got tangled easily and when testing each individual screen that wasn’t working this made it difficult to find the correct connections. This issue was accelerated by our decision to dispense of numeric labelling conventions, connecting any Arduino to any OLED in any dome. Such a choice made troubleshooting less a matter of, “Screen 24 is down, something’s up with Nano 24,” and more a matter of, “This screen is down, check all of the Nanos.”

 

Troubleshooting

With each individual dome hooked up, we tested if the nanos and screens would power on. Initially, none of the nanos had any power. The DC power jack’s positive and negative terminals had been bridged by spare solder, bypassing the assembly entirely. This was solved by de-soldering the jack completely, cleaning the site of its connection, then re-soldering it with extra care taken.

With that fixed, we realized most of the screens had no power or just would not turn on. In part, this was due to the aforementioned wiring reversals in the OLEDs. The screens which had their wires reversed were burnt out, and needed replacing. This largely happened in the desert dome; the final one to be installed.

Problems in the desert dome were compounded by a lack of distinction between power and signal cables, which was not resolved due to time constraints.

Some screens resisted all troubleshooting. In some cases, swapping out either Arduino or the screen itself solved the problem. In other instances, the issue could be resolved by finding loose jumpers. However, a rare few simply resisted all solutions, and so remained unsolved.

 

Thoughts on the Prototype

For next time a different organization system of wiring would have made this quicker and more simplified to go through, labelling each wire and OLED with a specific number so we could tell what wasn’t plugged in properly and which ones weren’t functioning correctly and make a note of that. As it was, when we opening up the wiring box when there was clearly a couple of shorts going on, there was no way to sort through them besides the labels that we had put on all of the data cords. At that point we had to individually go through each wire and arduino to see where the problem was and if anything had been fried or plugged in wrong.

As for the OLED screens and creatures themselves, another organization system that would have been beneficial would have been assigning numbers and domes to each person in order to properly know which OLEDs hadn’t been turned into us or were having difficulties.

 

Wiring Images/ Materials:

https://docs.google.com/document/d/1rawrmO6kliL9iuReL6c0J6kpSfLHgz1fyNdyetbeMzw/edit?usp=sharing

Process photos:

https://drive.google.com/open?id=1U09chxDF3O6l_l2RF31EH_TZpDpDrJty

 

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