This is the first time I've used Eagle. I've made this device already, it works pretty well. The basic idea of this is it takes the power routes it through a mosfet to turn on a motor when the attiny gets a signal to do so from the IR Sensor control wire. One time it was stuck in the on position...still haven't figured out why.
This is an update I'm doing to it to replace the proto boards with printed ones. But I've basically eliminated the Arduino and replaced it with an ATTINY85. To reduce the voltage from my 9v wall wart, I'm using a voltage regulator vs some diodes in series in the previous design.
I'm not too sure about the capacitors. I am going to use ceramic ones and I determined the sizes on it based on what I read on a website or datasheet, I can't remember where. So do I have them all in the right place, need any more, right sizes?
Also if you can think of any thing else you see wrong or think I could use on here instead I'm open to suggestions. I'm still pretty new at this.
ATtiny should have its own 100nF cap from VCC pin to ground. This is separate from the one coming off of the regulator. This should be located as physically close to the VCC pin as you can reasonably assemble. I would also add a pin out directly to pins 1 and 5, just so they don't lost on your board if you turn out to need another pin.
Xpendable:
Maybe a pin header for programming your chip? Would save you from having to pop it out of a socket to program.
I only have my arduino to program it with. I'm going to be using this guys, http://highlowtech.org/?p=1706, website to program with. I've never done this before. So it would be better for me,especially if I mess it up, I can then replace the chip.
mirith:
ATtiny should have its own 100nF cap from VCC pin to ground. This is separate from the one coming off of the regulator. This should be located as physically close to the VCC pin as you can reasonably assemble. I would also add a pin out directly to pins 1 and 5, just so they don't lost on your board if you turn out to need another pin.
Is 5V enough to saturate the MOSFET?
Thanks
I will add the cap to the attiny. Do you think the capacitance I have is high enough for existing capacitors?
Good idea on the pinout.
VGS(th) for the MOSFET is 2.5V, so 5 is enough.
Kinda funny that you called the signal coming from Pin6 "PIN1".
How much current does the motor need?
Why not power it with a 6V wallwart and ditch one of the regulators? http://www.dipmicro.com/store/DCA-0610
Then use a Low DropOut (LDO) regulator for the 5V
something with Vin = Vout +1V or less.
Or 4.5V even if the sensor will accomodate that.
Because on the chip it's internally registered as input one and has to be referenced as so.
The motor ran off a handful of double a batteries before it was salvaged, so very little. I measured once but don't remember off hand.
I like that LDO regulator, I'll definitely keep that in mind. Thanks.
I use the 9V for a variety of things. It's simply what I have on hand.
Hi, good start to CAD drawing, just a suggestion do not be afraid to spread out your diagram.
That way your PIn1 and GATE flags can be eliminated, also put all your GND symbols vertical, try to get your text all horizontal if possible.
I think as you use eagle,(don't use it myself unless really needed) you will find all the fine tuning points, I'm sure there is a font and points parameter for the component text to make it smaller.
Actually, looking at the cap values on the inputs of the regulators (or regulator if you go that way), between 1uF to 10uF would be better. You can get a tantalum one for relatively cheaply in the same package size, though it is unipolar, so make sure you have markings and don't install it backwards. 100nF is a good bypass cap size.
