/diy/ - Do It Yourself

>>149120 nausea inducing from three peak wavelengths with nothing between?

The brain can't detect things in between; it just pretends to.

Human eyes only have three distinct color sensors. Their range of sensitivity overlaps, so we can identify something like purple light because it triggers both red and blue receptors by falling in the area where they overlap. If a red and blue light are shone at your eyes at the same time it looks purple because your brain has no way to tell if the two color sensors are being triggered by a wavelength in the overlapping region, or two separate red and blue lights. By taking advantage of the eye's limited number of color sensors we can convince the brain that an entire spectrum of light exists by just varying the intensity of three differently colored lights.

>>148063
This is my bike.

>>147444
They share a number of pins and do not have write enable inputs that would let you get around this.

For example to make one of the stepper motors move you pulse the Arduino's data pin 6.
Data pin 6 is also used to control which charecters are printed to the LCD. You can't write to the LCD without a stepper being told to move.

Count how many IO pins you require for the specific pieces of hardware you want. Count how many IO pins are available on the Arduino. If you cannot do basic math you are not ready for microcontrollers.


There are some tricks you can do to reduce the number of pins required:

Use components with a serial interface instead of parallel.
Put components on a databus when possible.
Put the switches in a matrix instead of a dedicated IO line for each of them.

Those paints don't just "dry" like a puddle. There's a chemical adhesion reaction. Chemical reactions usually go faster with increased temperature; but there's no guarantee that will be true in this case; or that it will adhere properly at all. There should be information available about the proper temperature ranges for the paint.

>>146701 2x old scanners
The cold cathode tubes make nice lights; especially on bikes.

I use the following through process whenever I have some object I don't know what to do with.

Step 1) Put LEDs in it.
There is no step 2.

I used the P89V51RD2 for years. It has an internal I2C bootloader, which was ideal for me since I didn't want to invest in a programmer. They cost $6 and come in DIP form.

My final electronics engineering project was a sound based touch sensor. Three microphones on any wall. User taps or scratches their finger across the wall; it triangulates the position, controls a mouse.

You know those come in all different sizes right? Try goggling the serial number.

>>144115 what makes an IR LED "high intensity."
The luminous output, measured in candelas or lumens . Your seller doesn't give you that information. Any LED drawing only 28 milliwats isn't going to have a particularly impressive output, but should be plenty for your application and the price is fair.

>>143899
Well that "686" on the third row down is probably the peak wavelength in nanometers, which is red. The top label I think says "20 W" for 20 watts, which is quite powerful. Bottom most label is a date I assume.

Analog electronics: Op-amps; Op-amps fucking everywhere.

Get yourself an op-amp chip. Build something simple like a sin wave generator using a capacitor and inductor. Maybe a couple more using variable capacitors, a circuit to add the waveforms together; some filters; etc.

Sergeant Pepper's lonely hertz club band-gap

Some people collect old bottles. Check what they're being sold for on eBay.

>>143235
Most really high end stores do that. Part of what makes their products valuable is that rich assholes want to walk around feeling smug they have something so expensive. If they see some prole with a Louis Vuitton handbag they no longer want to shop at that store.

Maybe try to drain the ink out with a syringe?

>>143219 battery suddenly surging when an electrode sponge dries out, falls off, etc.

Well that's not going to happen, but since a battery is a voltage source and you want a constant current source your plan is still valid. Someone with little to no prior electronics experience should be able to handle the LT3092; but are you sure electrocuting your brain is a smart idea?

According to: http://en.wikipedia.org/wiki/Transcranial_direct-current_stimulation#Safety_protocol
you shouldn't use more than 2ma. The LT3092 can go up to 200ma, which could cause brain lesions.

>>141639
This one's pretty good.
http://www.youtube.com/user/Starcross42

Also Khan Academy has a lot of videos on calculus and electrophysics. What you need to be prepared for when entering any engineering program is a lot more math and physics coursework than DIY type stuff in the lab.

>>140959
Only with a 5v Voltage Regulator.

It charges up through a 5v USB connection right? Cut open the charger cable and connect the red and black wires to a battery pack.

When given a project it usually only takes me a few minutes to think of how to Macgyver it out of common items. When I find some cool looking object months go by before I think of something to do with it.

>>139589
There are hundreds of tutorials for making an LED matrix on the internet. I don't think putting the matrix in a colander or programming it to scroll math is an important enough new feature to warrant lengthy discussion.

>>I would definitely be interested in knowing how you dealt with the large amount of info that might be required with respect to the flicker it could cause.
I had it refresh faster than 60hz. That's all there is too it. Get a light flickering faster than 60hz and humans can't see the flicker, it just looks dim.


>> I had trouble with my small matrix flickering during intensive draw routines.
Oh I get your problem now. What you want to do is add a timer interrupt. Its something that at a constant period makes your microcontroller stop whatever it's doing, go run another function (Interrupt service routine), then go back to what it was doing. In each Interrupt routine switch to lighting up a different column of LEDs. The led matrix will refresh at a constant rate no matter what else is going on in the microcontroller.

>>139586
I think you should sober up and come back to this thread later. You're not making a great deal of sense right now.