loading
12 Comments

Tell us about yourself!

Complete Your Profile
  • JamesW440 commented on noahw's instructable LEDs for Beginners2 weeks ago
    LEDs for Beginners

    I suspect that your situation is long since passed, but I think a single 3 vdc 2032 would run all of these lights if hooked in parallel. In other words, the two lights should have been wired in parallel, not series. I am assuming that these are LED lights. Place all of the switches where they will be located in your model. Once the switches are in place, wire the battery plus (+) to each switch. I am assuming that your switches are only going to 'break' the plus (+) line.Start with a wire that runs to the nearest room from where you want to place the battery. Run the wire from the battery plus (+) to the switch and then from there to the next nearest room's switch and so on until all seven switches are connected on their input side. (It might be easier to connect all of the first floor ...see more »I suspect that your situation is long since passed, but I think a single 3 vdc 2032 would run all of these lights if hooked in parallel. In other words, the two lights should have been wired in parallel, not series. I am assuming that these are LED lights. Place all of the switches where they will be located in your model. Once the switches are in place, wire the battery plus (+) to each switch. I am assuming that your switches are only going to 'break' the plus (+) line.Start with a wire that runs to the nearest room from where you want to place the battery. Run the wire from the battery plus (+) to the switch and then from there to the next nearest room's switch and so on until all seven switches are connected on their input side. (It might be easier to connect all of the first floor on one line and then all of the second floor on another line, but that part doesn't matter.) When all of the switches are connected on the plus side, connect the lights in each room to the plus (+) side of each light and then to the other side of the switch it will be operated by. None of these light connections should go to any other switch - just the switch in that room and NOT to the battery minus (-). Now all of the minus (-) side connections of the parallel lights should be run to all of the other minus (-) connections so that all of the minus (-) side connections are together and attached to the battery (-). One CR2032 should run all of it and the switches should control each independently.Now I suspect that there is a reason for wanting to wire the house and then show a resulting fault that an earth quake or something like that would have on the wiring as the house falls. You might want to wire each switch directly from the battery plus (+) to avoid a portion of the house falling from taking the power away from the rest of the house. You could run the plus(+) and the minus(-) together to each switch, etc. Perhaps the young man knows what the teacher is trying to achieve so that you can route your wires accordingly.

    I think the main reason that they recommend them is that they understand them. It takes more than hooking wires together to make it work. Would you guys please explain how you get this microcontroller to do anything at all? I think that you have to write a program, don't you? And don't you have to understand how to write that program into the controller as well? Can you modify the program when you find it doesn't work? Don't get me wrong because I think you are right. But we tend to go with what we know. This might all be fun for you, but not so much for someone who doesn't have the knowledge or inclination to attempt it.And another thing, I worked on a tractor that had an instrument panel operating off ordinary electric gauges. It had broken and for $200 the people who owned the tracto...see more »I think the main reason that they recommend them is that they understand them. It takes more than hooking wires together to make it work. Would you guys please explain how you get this microcontroller to do anything at all? I think that you have to write a program, don't you? And don't you have to understand how to write that program into the controller as well? Can you modify the program when you find it doesn't work? Don't get me wrong because I think you are right. But we tend to go with what we know. This might all be fun for you, but not so much for someone who doesn't have the knowledge or inclination to attempt it.And another thing, I worked on a tractor that had an instrument panel operating off ordinary electric gauges. It had broken and for $200 the people who owned the tractor replaced it with one that uses a microcontroller. It worked for awhile and then broke again. I looked at both the old one and the newer one and found that the old one was still operable, but I could get nowhere with the newer one because I couldn't find any specs on the microcontroller. I fixed the problem with the original analog panel and it works fine. (BTW, the problem was that the ammeter in both units overheated and burned things up. (There is no connection between the ammeter and the other gauges except proximity.) I could find no reason for the overheating so I took the ammeter out, tied its input and output wires together outside of the instrument panel and replaced it with a cute little digital voltmeter. No problem since.)

    The situation here is what resistor do you use when the LED and the voltage source are the same? What should be done to overcome the 'no resistor needed' situation? You can approach it by increasing the supply to a higher value or look at the spec sheet to find out just where 1.7 v is and where 20 ma is with regard to the device specs. If the 20 ma is the optimum operational current for the diode, then design to that current. If the light output doesn't change appreciably, try using a lower voltage. That is, suppose the diode works ok at 1.5 vdc at 20 ma. 1.7 - 1.5 = 0.2 v. At 20 ma the resistor in series with the diode would have to be 0.2/0.02 = 10 ohms. That would work, but the resistor really should be larger, so it would be better to up the source voltage if you can. The 10 ohm re...see more »The situation here is what resistor do you use when the LED and the voltage source are the same? What should be done to overcome the 'no resistor needed' situation? You can approach it by increasing the supply to a higher value or look at the spec sheet to find out just where 1.7 v is and where 20 ma is with regard to the device specs. If the 20 ma is the optimum operational current for the diode, then design to that current. If the light output doesn't change appreciably, try using a lower voltage. That is, suppose the diode works ok at 1.5 vdc at 20 ma. 1.7 - 1.5 = 0.2 v. At 20 ma the resistor in series with the diode would have to be 0.2/0.02 = 10 ohms. That would work, but the resistor really should be larger, so it would be better to up the source voltage if you can. The 10 ohm resistor is better than none.

    Nothing wrong with a voltage divider circuit. There is also a thing called a voltage regulator that will do an astounding job at maintaining the voltage at whatever it is designed to produce. Some have built-in adjustability. Others are set voltage like LM7805 which is a 5 vdc version (and inexpensive), so you would need to find a 6 vdc version. In fact there might even be one built into the device, but I doubt it. If so, it might handle 9 vdc.And, no, they won't take what they need and disregard the rest. It depends on what is in the package that runs the device at 6 vdc. If it has a regulator or a voltage divider that somehow handles the 9 vdc, you will have lucked out. Otherwise, you have toasted it most likely.

    View Instructable »
  • Stop using Ferric Chloride etchant!  (A better etching solution.)

    This is a neat method. I would suggest looking into the 'sponge bath' method that another person used for Ferric Chloride etching. That method should work with these chemicals and allow one to make only enough to etch the current project plus not overheat everything because you have control over how much etching is going on at any given time. I would not want to risk putting that much time and money into making a pc board and then have it etch so fast that it overheats everything. You might be a little apprehensive about putting your hands actually into this stuff, but use a slower reacting mix and it should do fine.

    There is a pure 12% hydrogen peroxide available, but it is expensive by comparison. You can google it. I would not recommend using that peroxide you found with that other stuff in it! To make the adjustment from 12%, you do ratios 0.12 per unit vs 0.03 or 12/3 = 4 so you need 1/4 as much 12% to get the equivalent of 3%. Then adjust the volume for the amount you want to mix. As far as the acid/peroxide turning brown, it sounds like you got some sort of reaction - were you using Muriatic acid, or something else (a combination cleaner of some kind)?

    If you have 10% and you need the amount that would be required to equal 30%, you just do ratios. So you need 3 units of 10% to equal 1 unit of 30%.Adjust the total amount of liquid volume to get the right volume. So 2 units of peroxide with 1 unit of 30% gets 3 units of volume. To adjust that to use the 10%, you need 3 units total so 3 units of 10% plus 2 units of peroxide is 5 units 3/5 + 2/5 = 1 so 3 units would be 9/5 + 6/5 or 15/5 = 3 units. Put another way, you need 1.8 units of 10% acid and 1.2 units of peroxide to make the 3 units, not 1:1. So your etchant should have worked considerably slower at 1:1.

    View Instructable »