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Start with the Arduino mouse/keyboard libraries. They're quite small.

Repair / Re: Repair a PAN 8209. A challenge for you !!!
« Last post by retiredcaps on Today at 08:23:58 AM »
In continuity I have seen less, but also it randomly doesn't work as you can see in the video. (photos of inside at the final part)
Let's start with a clear focused still picture of the pcb (both sides).  The photos in youtube are not good enough for me to see.

It isn't an economic issue, DMM is more or less cheap so it could be thrown away, but sometimes we do challenges for ourselves: could I repair it?
Yes, I repair low cost items generally for fun, challenge and learning purposes.

Anyone know where I can start?
In some of these low cost meters, I suggest checking the range switch for dirt/debris/contamination.  Bad or cold solder joints can also be problematic in low cost meters.  Clear focused well lit pictures will help us help you.  If I can't reading the silkscreen writing on the pcb, then the pictures are not good enough.
General Chat / Re: Windows backup
« Last post by Sredni on Today at 08:20:43 AM »
I know it's not a "real" backup, but for just copying over my work files I use mirroring with "robocopy" on a regular basis, or I will use FreeFileSync ( to just mirror over all my important files to an external HDD.

I too use FFS for syncing my docs between desktop and laptop (via USB pen - I'm too paranoid to rely on online tools). It's nice and it manages conflicts allowing the user to choose what to do in case both versions of a file have been changed. Being paranoid (and a stingy cheapskate) I stopped upgrading it when I saw the word "advertisement" in their download page. My mind went right into OpenCandy mode and I literally closed the browser. With a padlock. And a concrete sarcophagus.

So, today when I searched for the above link, I learned OpenCandy is defunct. 

Do you guys know if the latest FreeFileSync installer is a clean "one ad only and nothing installed or hidden in the registry except FFS" honest installer or is it using some other opencandy copycat?
Test Equipment / Re: Silent fan for tek dpo3000
« Last post by nctnico on Today at 08:14:17 AM »
I'd try rubber fan mounts first. Chances are the noise gets coupled into the scope's casing.
Crowd Funded Projects / Re: Light phone on Kickstarter
« Last post by edy on Today at 08:10:55 AM »
I think they've completely lost their minds. The Google ads are just showing outlines of a new device. Light Phone just photoshopped their phone design on top of the Google ad and changed the date to their NY event on Oct. 5. By absolutely no stretch of the imagination is Google copying anything. In fact, Google probably never heard of them. They are delusional!
Other Equipment & Products / Re: Inexpensive Sot-23 hot air setup
« Last post by KL27x on Today at 08:10:36 AM »
I don't need to apply additional flux. What's in the solder is plenty.
This is true for a one-off. For doing 2 per board x 100's or 1000's of boards, the flux is for speed. Holding solderwire in one hand, iron in the other, and tweezer with your toes... not good. :)

Flux boards. Place parts with vacuum pickup. Using a large bevel/spoon or TFO bevel loaded with a huge blob of solder to dot the pads and you can hold tweezers with your other hand. 6+ at a time without stopping. Touch once to top of the part, once to the bottom, and you get pins 1 and 2 at the same time. TFO is best, IMO, because you can tilt the tip to touch a smaller area without the blob sliding off onto the side of the tip. You can control a huge amount of solder with 3mm TFO.

I got paste and a small reflow oven and hot air, and soldering iron is way fastest for doing 2 SOT 23 per board, IMO. I can't imagine why not, provided you have room enough to maneuver the loaded iron. For removing them, it's the opposite. A bevel tip with blob of solder works fine for one-off. Hot air nozzle faster for removing a lot, because you don't have to mess with removing the parts from the iron and replacing the solder blob. Just place small nozzle over the SOT and flick to the side. :)
Test Equipment / Re: EEVBlog Members Discount at Tequipment?
« Last post by shogo on Today at 08:08:58 AM »
Asking for a discount code also!  :)
Beginners / Re: Question Regarding Diodes in Schematic
« Last post by ataradov on Today at 08:07:53 AM »
Audio input is SGND and IN signals.

This circuit will require a lot of tweaking, it will not work out of the box. Also, breadboard is no the best way to prototype this, stray capacitance of the breadboard will make it a nightmare.

Also, start building it from the end. Build one indication chain and see how it works if you feed it with different voltages, then build filters, then buffers, etc.
Test Equipment / Re: EEVBlog Members Discount at Tequipment?
« Last post by redshift on Today at 08:07:47 AM »
May I have a discount code as well please? :)
Beginners / Re: Oscilloscope bode plots
« Last post by AlfBaz on Today at 08:03:43 AM »
bson has articulated why this method has its pitfalls, which I found out by actually doing this.

I used a wavegen's "sync out" as the reference phase and fed this into my lecroy scope along with the signal from the DUT.

I then used GPIB, and labview to control the wavegen and ask the scope for phase difference between "sync" signal and DUT signal, as well as the latter's amplitude using the scopes measurement utilities.

I collect this data for each frequency point and average the result. I then increase the wavegens frequency logarithmically and repeat for the number of points chosen until the desired upper frequency is reached. I use the wavegen's output impedance of 50 ohms as the reference reisitor, allowing me to simply test hook straight up to the DUT. Finally I graph the data with appropriate scales

The results are not terrible and seem to lay somewhere in the realm of where you would expect. Not having a VNA, I cant check the results against a known correct bode plot.
I suspect carrying out a calibration routine (as outlined by agilent in an impedance primer I forget the name of) would greatly increase its accuracy but stumbled upon major issues concerning delay between "sync out's" output and the actual triggering of the sine wave output which increases dramatically as you increase the wavegen's output

Attached is an image of what is essentially a LPF using the wavegens 50ohm output resistance and a 0.1uF cap
In this plot there is an obscene number of data points. The glitches you see are where I have to change the scopes timebase and volts/div as the wavegens frequency increases and the DUT amplitude decreases so that the scopes measurement functions have a chance at giving me decent results

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