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Running BS2 HomeWork board nonstop? — Parallax Forums

Running BS2 HomeWork board nonstop?

IceFireProIceFirePro Posts: 86
edited 2010-06-09 05:32 in BASIC Stamp
Hello, I am pretty new, just got my BS2 stamp and I'm curious about certain things, as I have good experience with BASIC language from before and I am into some more interesting projects that I can do with the stamp.

Question: If i power the HomeWork board with a DC adapter, can i keep it on all the time (for example, run a program that turns on the lamps on my model railroad at night and stops them in the morning); would such thing damage the board (running all the time)?

More on DC adapter: In the manual they say I should use a 6V adapter, although that the battery it takes is 9V - why?

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2010-06-08 15:12
    The HomeWord Board or any other Stamp board should be able to run continuously, day after day. Several people have commented about commercial or industrial projects that have run uninterrupted for well over a year.

    The Stamp (and any logic on your board) uses 5V which is provided from a voltage regulator on the board. The regulator takes any excess voltage and dissipates it as heat. By using a 6V adapter, you minimize the heat produced. The HomeWork Board is designed to use a 9V battery because it's small, light weight, and relatively cheap ... a good choice for an educational environment. Most small (educational) projects won't draw too much current from the regulator, so the extra power that has to be dissipated is not that important. For permanent projects, a 6V adapter or a 6V battery pack using 4 AA alkaline cells. If you want to use rechargeable cells, you'd need 5 of them (5 x 1.2V = 6V).
  • IceFireProIceFirePro Posts: 86
    edited 2010-06-08 16:15
    You are the man, as they say [noparse]:)[/noparse]

    So, in such case, Vdd and Vin will have almost the same characteristic?
  • Mike GreenMike Green Posts: 23,101
    edited 2010-06-08 16:29
    Not quite. The Stamps use what's called a low dropout regulator. Some of these can maintain accurate voltage regulation with as little as 0.5V difference between the unregulated input and the regulated output. Vdd will remain at 5V as long as Vin is at least 5.5V.
  • IceFireProIceFirePro Posts: 86
    edited 2010-06-09 02:57
    Well, that's what I'm asking - if I'm using the stamp with a 6V adapter, Vin should be 6 V, and Vdd will be around 5V, right? But maybe different amperes on the two outputs?
  • Mike GreenMike Green Posts: 23,101
    edited 2010-06-09 04:40
    You need to learn Kirchoff's Law. It's a basic property of electrical circuits. Think about water flowing through a hose system as an analog to electricity. The pressure is the voltage and the flow volume is the current. What determines the water flow into the system?
  • IceFireProIceFirePro Posts: 86
    edited 2010-06-09 05:32
    Well, in the case with 6V adapter, it's amperage should determine the current being directed to Vin, right?
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