Recent content by positron

OMG :o Do you light your living room with 50 candles or buy a light bulb? ;D

Hi Mike, I don't know if this is any help to you at all, but these guys: http://endless-sphere.com/forums/viewtopic.php?f=14&t=8273&st=0&sk=t&sd=a used some A123 lithium batteries to start a car with. Might be worth a look if no one else finds what you are looking for. cheers, Alex

I'm no expert, to me it looks like R4 will be pulling the gate of the mosfet high all the time causing it to be switched on constantly. What happens if you remove R4?

haha, cheers ;D

That makes sense. In case anyone is interested, you can get 20 for $6 shipped from here: http://cgi.ebay.com.au/20pcs-N-Channel-Enhancement-MOSFET-60v-5-amp_W0QQitemZ120363476625QQcmdZViewItemQQptZBI_Electronic_Components?hash=item120363476625&_trksid=p3286.m63.l1177 I have attached an English...

Re: Step by step guide to making a 3W RGB moodligh Thanks for that :) I have no idea about jal so I will just use the hex I think.

Thanks for the explanation. It makes perfect sense, if the battery is dropping to 2.6V or something and the mosfet is not turned on very hard it will be dropping voltage as well as the sense resistor so the ld will be left with less voltage. (at least that's how it sounds in my head :)) How...

Re: Step by step guide to making a 3W RGB moodligh Are you saying that you have some code that will work for this project? :-?

Re: Step by step guide to making a 3W RGB moodligh Thanks for the tutorial. I would like to build this if I can get some free time :) Assuming we have the technology to program one of these little suckers and have a blank 628 on hand. Would the hex file / source code be available for us to...

The 2SK1112 has a gate threshold voltage of 2V max and a drain current of about 3 amps with a gate voltage of 3V. I'm pretty new to this stuff but I thought those figures would make it a good candidate for this driver and in my breadboarding I was getting a dropout of about 0.2 V with a ld...

Try this driver by kernelpanic: http://www.laserpointerforums.com/forums/YaBB.pl?num=1220866048 Don't use the very first schematic posted, use the second one posted by kernelpanic. It uses an opamp and a mosfet and will work with very small voltage difference between the batteries and the...

Re: Adjust your laser's output on the fly(digital Sounds like a cool project :) With the digital pot, you could probably do away with it entirely if you use PWM into a RC network to give a variable output voltage that you could feed into your circuit instead of feedback directly from a...

Re: Adjust your laser's output on the fly(digital I reckon you are right, if you just use an output pin with variable PWM connected to a logic level fet you could adjust the brightness that way by directly switching power on and off to the LD. It would be more efficient than using a linear...

You probably want at least a couple of hundred mA to get burning power. The USB spec guarantees 100mA. If you want more, you can request up to a guaranteed 500mA by making the request through the USB port so unless your device can communicate to the USB controller to request the extra current...

Without caps the voltage regulators can oscillate and get hot because of that. You would only be able to tell if that is happening with a scope though.