However, I would like to be able to do the display part wirelessly. I.e., somehow I’d like to have a set of LEDs (or possibly just one LCD) that I can control remotely. So my PC would run, and send the relevant information/control signals to periodically turn on/off LEDs/LCD. The distance is only a few meters, and the data will not be highspeed. Oh, and I’d want the display to be powered via battery (so no long USB cable) … would this eat through batteries quickly? I could probably do with a set of 4 or 5 LEDs.
I’m thinking of getting a Arduino starter kit (either this http://arduino.cc/en/Main/ArduinoStarterKit or http://www.makershed.com/Ultimate_Ardui … msump1.htm – is one better than the other?). To do the wireless part I think I should get two Xbees (series 1) … does that sound right? Do I need to get some other small boards to setup the Xbees? From some videos I’ve seen it seems I may have to?
Can I do this with just one UNO? Do I need anything else? Any specific information would be really helpful since I’m new to this.
Thanks for any guidance, I’m quite excited by all of this
You need one of the XBee Explorer boards to configure the XBees w/X-CTU on your PC. I’m not an XBee guru but if you have that board and XBee connected to your PC and the PC knows when the ISS is overhead, then a script running on the PC should be able to communicate a simple on/off signal to the remote XBee. The remote XBee could then turn on the LEDs, through a driver circuit, via it’s one or more of it’s 8 digital I/O pins. I don’t see a need for an Uno unless you want to do something fancy. Even then a lot could be done by software running on the PC. At the remote end you’d need the XBee, a board of some sort to plug it into, the batteries, LEDs, driver circuit and perhaps a voltage regulator.
As for battery life … what’s acceptable to you ? I checked @ Heavens-Above and the best case has the ISS overhead 4 times in a day for me. The longest time overhead was about 6 minutes. So the best day is the worst case for battery life, where the LEDs are on 24 mins/day. Let’s call it half an hour. If 5 LEDs draw 20 mA each, then they use 50 maH of energy on that worst day. If you use common 2500 maH NiMh AA batteries then that’s (crudely) 50 days before the batteries run dead. Now I’ve not included the power draw of anything else but then again most days the ISS is only overhead 1-2 times for less than 6 mins each. The real question is how can you manage the power of the XBee (and perhaps a voltage regulator). The XBee has some sleep (low power) modes and so you need to research how they work and if sleep can be automated or commanded from the PC XBee and how the remote wakes up. With good power management I’d guess a 2 month time is still very achievable.
If you want to use some graphical LCD display then you’ll need an Arduino (which also has sleep modes) of some sort and the above guesstimate will need redoing.
Thanks so much for your informative message. I hadn’t even considered the possibility that this might work without the UNO. I’ll probably still get the starter kit, but it would be nice to be able to set this up without tying up the UNO if I can
Your post also gave me an idea on how to estimate power consumption, again, something new to me. I’ll be ok with the LEDs, especially if that lets me create a minimalist setup.
I’m sure I’ll be back with more questions once I get the necessary hardware. Thanks again.
