-----Original Message-----
From: Jon Wallace <jonw@psubs.org>
To: personal_submersibles <personal_submersibles@psubs.org>
Sent: Fri, Apr 13, 2012 3:54 pm
Subject: Re: [PSUBS-MAILIST] Controller/Display
I received my joysticks from Trossen Robotics ($25 each) and they are
factors nicer than the thumb-sticks typically used by micro-controller
enthusiasts. There's a bit more "play" at the top/bottom end than I had
hoped for but overall the stick is nicely matched to the
potentiometers. Haven't measured it, but adc 0 & 1023 occur about 3-5
degrees before end of travel on either side of joystick travel. I think
this is going to be fine.
http://www.trossenrobotics.com/p/medium-robot-controller-joystick-2D.aspx
I've also received all my environment sensors and connected them to the
arduino uno microcontroller. I'm running out of inputs however so I
also ordered an Arduino MEGA which was cheaper than purchasing
additional ADC inputs and then spending the time to connect and get them
to work with the uno. Currently have water depth/pressure, vertical
rate of descent/climb, water temp, cabin temp, cabin humidity, cabin
pressure. All sensors have very good accuracy except for the Humidity
sensor which is 3.5%RH over 0-100% scale. Turns out it is a bit worse
than that, somewhere around 5%. But it's not a critical sensor and
whether it shows 100% humidity or 95% humidity in the cabin probably is
not going to make a lot of difference. If anyone knows of a more
accurate analog humidity sensor I'd like to hear of it. Couldn't find
one on digikey or mouser. I'd have to go to I2C or SPI interface to
bump up to a .5% accuracy which I may end up doing, but it means more
software code and processor instructions. The software will allow two
options for cabin pressure, current pressure display and pressure change
since closing the hatch. The cabin pressure sensor matches the pressure
sensor in my Analox Gas Monitor exactly and has a resolution of about
.03 psi.
Temp Sensors: LM74 (yeah, yeah, I'm still on the english system)
Humidity Sensor: Honeywell HIH-4021-003
Pressure Sensor (cabin): Honeywell SSCDRNN030PAAA5
Still have not decided on building or buying a motor controller yet.
Jon
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