PCB Jig + Lab Power Supply #DIY

I recently added a couple home-build devices to my home lab. The first is a well-designed PCB jig engineered by an electronics forensic expert. The second is a very cheap lab power supply using a Chinese step-down converter and an old battery charger.

The Jig

It seems I never have enough hands, especially while testing and troubleshooting a fresh PCB. As frustration was mounting recently, Thingiverse member Giufini seemingly heard my prayers – and shared his design for a PCB probe jig!

Thingiverse photo

At first glance, it looks somewhat hap-hazard. I built one, and must say that it is very well designed! The layout of the board is perfect for the PCB’s I work with. The towers and arms are easy to adjust and have a well-tuned flexibility to them. Finally, the acupuncture needles were simply genius! This design was even reviewed (and quite well received) on Superhouse.

PCB Probing Jig DIY

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500W Spindle Controller – Fixed!

You Get What You Pay For

While building my CNC mill, I bought a 500W spindle with a motor controller off eBay for less than $80 CAD.  The spindle and power supply needed some TLC right out of the box, but seemed to work fine.

Image From eBay of 500W Spindle & Controller

Then the incident happened… I was adjusting the ‘MAX’ potentiometer when suddenly the motor speed dropped to 5,000 RPM and wouldn’t increase!  I may have accidentally shorted the potentiometer with my screwdriver, but that shouldn’t have caused a problem.  This potentiometer is basically shorted to 0 ohms at one end anyways.

No adjustments to any of the potentiometers would change the motor speed more than a few hundred RPM.  I considered buying a replacement controller, but for $50 CAD I decided to have a crack at repairing this unit.  I ended up writing an almost-complete schematic of the controller and determining what one of the three IC’s are.

Schematic for 500W Spindle Controller / Power Supply

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High-Speed LED Pulsing Experiments

This page is currently being populated with past experiment data.  All future experiments will be added shortly after their completion.

The plans for Edgerton are available for anyone to build their own high-speed flash.  I designed the flash by building a prototype and doing lots of testing.  Until now, I haven’t kept an updated log of all the experiments performed on the LED’s.  Maybe some people would like to see all the details behind the designing and prototyping of the flash.  Others may be interested in designing their own high-speed LED flash.

The complete experiment logs can be found at github.com.

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Cheap Spindles & Power Fluctuations

While building my CNC mini-mill, I purchased a 500W air-cooled spindle from eBay.  It came with a power supply, which looked great and I (falsely) assumed it would work perfectly on my home-built mill.

Boy was I wrong!  The mill worked great as long as the spindle was turned off.  Whenever the spindle was on, there was a chance that the mill’s microcontroller would reset (bad), lock up (worse), or would suddenly enter an infinite loop (really really bad!) and an axis motor would begin moving in some direction until I noticed and stopped it.

After much work identifying and rectifying the causes, the power supply has finally been tamed.  Here’s a guide for anyone having the same issues.

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