Wednesday 3 May 2017

Assembling the light-up guitar

Things have slowed down a little bit, as assembling the guitar has proved to be a little more difficult than designing the electronics and writing the firmware!

The first thing to  do was make a note of the existing connections - just in case anything accidentally gets snipped or un-soldered. Then we whipped the scratch plate off and set about it with a Dremel and a small routing bit to make a window for our LCD display.

That triple-layered plastic made a right mess! Copious amounts of hot glue ensures our screen shouldn't be going anywhere, any time soon.

We took out the second tone knob (the one that's almost always left fully dialled to ten) and replaced with a fixed-value resistor. After all, the tone knob on these cheap Strat copies doesn't boost any frequencies, it can only choke them. And what's a Strat if it's not got that bright, jangly sound? Why would you want to dial that down anyway? So off came the pot, to be replaced with a fixed 220k resistor. In it's place we fitted a rotary encoder.

After cutting down the shaft and putting the tone cap back on, you'd never even know it had been modified if you weren't looking closely! Also added a stereo jack socket which we'll use to connect to the power/ground/RX pins of the microcontroller to allow data to be pushed into it at a later date.

Now for a really important part - lining up the neck and bridge. On a previous build, we missed this step out; fixed the neck, drilled the holes for the bridge, installed the tremolo system and found that the bass strings were almost in the middle of the neck and the high treble strings were fretting out, as the high E string was barely on the neck!

No chance of that happening this time around - some lengths of cotton allowed us to see where the strings would end up, to ensure we got the bridge in the right position this time.

You can see where, under the scratchplate, we had to do some extra routing to create a cavity for the LCD screen and 3000mAh lipo battery. A quick test fit made sure that everything was going to fit inside the cavities when assembled.

The firmware isn't quite finished yet (need to add in a couple more fancy patterns and recreate our earlier volume meter effect) so we're not quite ready to close it up and fit the strings. But that time is coming. It's coming real soon......

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