Yeah yours seems alright too, but i need the nine volts, because i can get more specific peak voltages for the leds and have room for expanding, also the nine volt fits better in my case than the 2xAA or 3xAA so thats why. I will post pictures when im done, also i will inform gordo on msn.shadow wrote:awesome.
just a thought-
i wanted an 8 led tv b gone, so i just made my own board with 4 resistors (47ohm), 4 transistors, and 4 leds, and conected all the resistors to the original resistors on the unit (so the microcontroller supports 8 ressistors to trans etc.). in works.
although you all might want the nine volts though.
just thought i'd share
-Shadow
Doubling the LEDs?
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Re: Actual!!
For anyone that wants the eagle files, i will release them soon, their based on opposums single sided pcb design, because for the regular home user, single sided is alot easier than double sided, becuase double sided requires tinting and silkscreening. A good site is futurlec.com for parts, most of the world shipping 4 dollars, and really cheap deals!!!
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hgds wrote:Yeah yours seems alright too, but i need the nine volts, because i can get more specific peak voltages for the leds and have room for expanding, also the nine volt fits better in my case than the 2xAA or 3xAA so thats why. I will post pictures when im done, also i will inform gordo on msn.shadow wrote:awesome.
just a thought-
i wanted an 8 led tv b gone, so i just made my own board with 4 resistors (47ohm), 4 transistors, and 4 leds, and conected all the resistors to the original resistors on the unit (so the microcontroller supports 8 ressistors to trans etc.). in works.
although you all might want the nine volts though.
just thought i'd share
-Shadow
BYTHE WAY, TEH RESISTORS ARE NOT 1/4 WATT YOU DONT WANT THE RESISTORS WAY TO HOT, YOU NEED 1/2 WATT 33OHM RESISTORS!!!! YOUR CIRCUIT MAY FRY IF YOU USE 1/4 WATT.
Any ideas are welcome.
Also, for people that dont know, a transistor is similar to a switch basically, you have a base, a positive and a negative. The base is what delivers all the frequencies to the leds, when there is a current through the base, it is delivered to the leds, and the negative turns on basically, so when you click the switch, the current is aloowed to go through the negative and the base current flows through. The resistors are used to make sure the transistor doesnt overload, and the leds are safe. ALSO
Does anyone know any other projects i can do, i ordered the parts for this and the parts for a minipov3 anything else!!!?? NOT arduino, xobox, rf jammer, or midisense, or digg button rofl....
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- mooseheadm5
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Ehhh... Think you should check the math again. if the LEDs dropped 1.7V each that means the 33ohm resistor would drop 5.4V for a fully charged battery. Now, using Ohm's law (really, you should be able to do his without help, especially if designing your own circuits) you should see that I=V/R so the current through the 33 ohm resistor would be 170mA. Since P=VI or the more easily remembered W=VA (watts=volts*amps) you find that the power dissipated by the 33ohm resistor is 0.918 Watts. A 1/2 watt resistor might get fried. Now the 42.5mA going through each pair of LEDs is not past the peak current for these, so that should be OK.
- nginuity
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Right, a lot of micro's don't like much above 5 volts.woody1189 wrote:if you use the 7805 in a to-92 just for the chip you should be fine. im not sure if you're listening to what weve been saying but if you put for Vcc of 9v into the attiny85 you might kill it. That chip has a 5V max rating so you need to drop that down to below 5V.
I did a little research over at avrfreaks and according to this:
http://www.avrfreaks.net/index.php?modu ... jectid=102
It's got a working voltage of 2.7 to 5.5, so, theoretically, we could use a 7803 here as well to power it with 3 volts.
Now that I think about it, this would give another advantage I had not thought of: constant voltage. If you have this device battery powered, the voltage will continually go down from it until you deplete it. This means you are always going to be fluctuating voltage to your micro. With a regulator, it stays pretty constant. I don't know on an in depth scale how this sort of thing affects the microcontroller, and I may be out of my league slightly here, but it would seem to me that such a thing needs somewhat stable voltage.
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what if i added a resistor in the circuit where the attitiny gets power from.NGinuity wrote:Right, a lot of micro's don't like much above 5 volts.woody1189 wrote:if you use the 7805 in a to-92 just for the chip you should be fine. im not sure if you're listening to what weve been saying but if you put for Vcc of 9v into the attiny85 you might kill it. That chip has a 5V max rating so you need to drop that down to below 5V.
I did a little research over at avrfreaks and according to this:
http://www.avrfreaks.net/index.php?modu ... jectid=102
It's got a working voltage of 2.7 to 5.5, so, theoretically, we could use a 7803 here as well to power it with 3 volts.
Now that I think about it, this would give another advantage I had not thought of: constant voltage. If you have this device battery powered, the voltage will continually go down from it until you deplete it. This means you are always going to be fluctuating voltage to your micro. With a regulator, it stays pretty constant. I don't know on an in depth scale how this sort of thing affects the microcontroller, and I may be out of my league slightly here, but it would seem to me that such a thing needs somewhat stable voltage.
- mooseheadm5
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Just using a resistor might work, but may not be the best idea. The resistor will waste power and will eventually drop the voltage below the operating threshold of the chip. A voltage regulator is the way to go because it can provide stable, regulated power in a small, and very simple circuit. If you are new to electronics, read all of ladyada's tutorials, because they are great. Even for me, and I have had more than a few electronics classes in my time. It is nice to see someone jump right into all this. You seem to be asking lots of good questions.
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Yeah, truthefullly im thirteen rofl, and we dont learn this much in class, but my dad took electronics in uni and he knows everything, but i never told him the voltage the micro controller can handle. So i could use a 220 Ohm but im better off using a voltage regulator, do voltage regulators have ratings and stuff, or what? The only regulator i saw on futulec is http://www.futurlec.com/3V3_Regulator.shtmlmooseheadm5 wrote:Just using a resistor might work, but may not be the best idea. The resistor will waste power and will eventually drop the voltage below the operating threshold of the chip. A voltage regulator is the way to go because it can provide stable, regulated power in a small, and very simple circuit. If you are new to electronics, read all of ladyada's tutorials, because they are great. Even for me, and I have had more than a few electronics classes in my time. It is nice to see someone jump right into all this. You seem to be asking lots of good questions.
How does that connect to the board, and wow, it probably wont fit. What are other things i can do. I would prefer the resistor as its small, but if i did add one, what kind would i need for the microcontroller(1/4, or 1/2) and its 220 ohms alright.
For the leds, the resistor i would need would be a 120 ohm i think and would it be 1/8, 1/4, er 1/2
Last edited by hgds on Sun Aug 24, 2008 2:11 pm, edited 1 time in total.
- mooseheadm5
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Well, what I should have said was you need a pair of resistors in a voltage divider circuit. I would just do the voltage regulator. It is not a very large package and should fit OK. My question is this, Why do you need 9V? You probably don't, and 9V batteries are not as good as you might think. Go to ladyada.net and read the section on batteries.
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Ok, so i have a question, i need to have the circuit powered, i have 8 leds and everything else is the same as the regularcircuit board. Can i power those 8 leds on two AA's properly with good brightness?mooseheadm5 wrote:Well, what I should have said was you need a pair of resistors in a voltage divider circuit. I would just do the voltage regulator. It is not a very large package and should fit OK. My question is this, Why do you need 9V? You probably don't, and 9V batteries are not as good as you might think. Go to ladyada.net and read the section on batteries.
- mooseheadm5
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Yes, you can. Just redo the calculations with ohm's law. If you have 2 LEDs and they each drop about 1.7V then if you put them in series, you need at least 3.4V to get full brightness. You can either use a boost converter or more batteries. Now if you link them in parallel, then they would only require 1.7V at the input, so you can go for 2 AA or AAA batteries. If you do that, you will need a current limiting resistor on the LEDs. To figure that out, ohm's law (again, learn it, live it, love it) and you have 3.2V (if using alkaline) and you want a max of, say, 45mA through the LEDs. So 1.5V drop through the resistor, 0.045A, then R=V/I so 33.3ohm resistor. If you do this with just 1 resistor, and everything is in parallel, then you have 8*0.045mA total current through the one resistor so 360mA. A single 1/2 watt resistor of 33.3ohm resistor should do just fine.
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So my schematic that i made atmooseheadm5 wrote:Yes, you can. Just redo the calculations with ohm's law. If you have 2 LEDs and they each drop about 1.7V then if you put them in series, you need at least 3.4V to get full brightness. You can either use a boost converter or more batteries. Now if you link them in parallel, then they would only require 1.7V at the input, so you can go for 2 AA or AAA batteries. If you do that, you will need a current limiting resistor on the LEDs. To figure that out, ohm's law (again, learn it, live it, love it) and you have 3.2V (if using alkaline) and you want a max of, say, 45mA through the LEDs. So 1.5V drop through the resistor, 0.045A, then R=V/I so 33.3ohm resistor. If you do this with just 1 resistor, and everything is in parallel, then you have 8*0.045mA total current through the one resistor so 360mA. A single 1/2 watt resistor of 33.3ohm resistor should do just fine.
axisos.ca/tvbgoness.png
will work fine with VCC of 2xaa right, and the leds will be bright?
- mooseheadm5
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Please be positive and constructive with your questions and comments.