Picorder 2

From Squared Wave
Jump to: navigation, search
Logo for the Picorder project

This page serves as a repository of information I have collected as I acquire sensors and materials for my successor to the original Picorder. What began as wanting to make a single Tricorder replica is slowly becoming more of a set of standards for the picorder family of devices I want to make.

Sensing Goals

Basic ambient environmental; temperature, pressure, humidity and VOC (Volatile Organic Compounds). Ranged line-of-sight temperature sensing (very small envelope. 0°c to 80°c). Magnetometer, maybe something like spectroscope if I can find one that works. Electromagnetic interference of a very arbitrary envelope could be displayed using some kind of ADC and an antenna.

CPU

Raspberry Pi Zero W
My old favourite will return for this model. Power consumption was a MAJOR problem with the first Picorder, I have found a really good article on some ways to reduce power consumption. I am playing with the idea of using something like an arduino or just an ATTINY, but the Pi has so many advantages.

Shell

There are some options:

Mark 7 Tricorder Replica
I've acquired a prop replica kit for the mark 7 tricorder from Stapleton Productions.
1993 Playmates Tricorder Toy
For the prototype, this is easy to get and modify.

Input

MPR121 Capacitive Touch Buttons
Controller to use small metal pads for capacitive buttons for inputs. I found a good guide and software info for the Pi here.

Display

I haven't finalized a screen for this project. I might use either of the following

5110 3310 monochrome LCD.jpg

Nokia 5110 LCD screen
To provide low power information output to the user, and maybe to play some snake. I looked in a number of places to find a good guide on how to connect the Adafruit part I have with various descriptions around the web. I found this guide to have some important information, but the wiring information seemed incorrect. This guide lays out how to connect the screen properly..

TFT ST7735.png

Generic ST7735 LCD Display
In applications where power isn't as critical a screen like this can provide full colour rich interface. Use of this screen can be facilitated by specifically pushing data to this screen using the Luma python module (more work but perhaps less processor intensive) or by using FBTFT to use it as a display target (requires additional software modifications, but allows for generic computing functions to be displayed). The display I found (pictured) had no pins listed as MOSI or MISO (for SPI) but I found a pin chart in the Luma docs that helped.

Sensors

Bm860 VOC, Temp, Humidity, Pressure sensor
The BME680 is a basic environmental sensor. VOC is a nice added feature. This sensor will provide ambient environmental information. I've found a good guide for how to connect it to a Pi.
AMG8833 IR Thermal Camera
This is a VERY low resolution and low range thermal camera. It will basically only be useful for detecting dramatic temperature differences. It was relatively cheap so I want to include it. This sensor will provide inaccurate CONTEXTUAL temperature information at range.
MLX90614 Non Contact Thermometer
A cheap and accessible non contact thermometer. This sensor provides accurate specific temperature readings at range. This page looks fruitful.
An EMF sensor of some kind.
Probably a resistor on an ADC to give me basic environmental electrical readings. I found this site that shows you how you can use at AT tiny as an i2c device, which I could use with this guide to make a small EMF detector to read low frequency interference.

LEDS

As with the original picorder I want to make sure that this one has a feel of the actual prop. the TOS tricorder only had 3 indicator lights but the TNG tricorder is lit up like a christmas tree.

I'm going to try and include at the very least:

  • the four green indicator lights (alpha, beta, delta, gamma)
  • the front panel sensor array (the green ripple lights, the various and sundry sensor illuminations)
  • the EMRG button
  • the PWR button.
  • GEO, MET, BIO buttons.

ALPHA BETA DELTA GAMMA

Its always perplexed me that these indicator lights seem to ripple (light up and turn off one after the other) in different directions depending on the season of TNG you're watching.

It makes sense to me that the LEDs on the Tricorder should ripple from top to bottom (alpha to gamma).

I have read (somewhere) that the TNG Tricorder lights were changed by a prop maker to run in the opposite direction only so they could tell when their work was being used on screen.


Controller

I think in the interest of reducing processing load on the Pi I will just use the Pi as a clock and pulse a GPIO pin high and low to a number of decade counters to control the "look and feel" LEDS.

Software

New software will be written that runs on some of the basic concepts of the original Picorder program. It will not use Pygame though, which will provide considerable performance and power savings, hopefully.

Notes

To reduce power consumption:

  • Only draw to screen when sensor reading has changed.

scale would be a factor for determining; different decimal places would trigger different refresh rates.

Download

https://github.com/directive0/picorder2

Installation

PicorderOS requires quite a few python libraries to work.

Open a terminal and follow the next instructions:

  • We must first enable SPI and I2C for sensor and display communications.
    • Open Raspi Config sudo raspi-config
    • Select "Interfacing Options" (Item 5)
    • Scroll down to SPI and when prompted enable it following the onscreen dialogue
    • Do the same for I2C
  • Ensure you have Python3 and Pip3 installed (should already be there on Raspbian) sudo apt-get install python3-pip python3-dev
  • Install Sensor Libraries
  • Install luma.lcd for the displays sudo pip3 install luma.lcd

User Interface

Picorder 2 will us PicorderOS and so there are a number of display options available now. More info to follow.

I have given some thought to how I want the device to be usable by the operator. I'm hoping to make as many functional buttons as possible, but its difficult to determine what the best course is. For the meantime I've made this rough design for a standard bar graph readout. This style of information display seems congruent with the LCARS interface seen in the show.

Basic Temperature Reading UI

Gallery

MyCorder

This project is a "MyCorder" build and so I'm using this subreddit to solicit advice from the community.