About Charles Pax

Charles Pax is the founder of Pax Instruments. Charles is the former Director of Research and Development at MakerBot Industries, having developed the MakerBot Replicator 3D printer.

Thermocouple connector prototypes

Two months ago we completed our thermocouple connector design and sent it off to the sheet metal factory. They said we would have prototypes by mid June. As expected, they were about one week late, which is pretty normal. Then they wanted more time. We pushed the factory to give us prototypes before the Dragon Boat Festival in late [...]

By | July 7th, 2015|T400|

Diodes – Types and Applications

Learn all about diodes, their types, and applications. In semiconductor and electronics industry, a diode is a widely used discrete component. It is a significant element in many electronic circuits and applications ranging from low power signal circuits to power rectification. Based on the functions and ratings, there are different types of diodes. However, all [...]

By | June 9th, 2015|Learning, Notes|

Othermill review

CNC mills can be better than etching if you're not interested in dealing with chemicals. The Othermill will even take care through hole drilling. The main challenge with DIY PCBs is still dealing with vias. Once you calculate the cost of all the equipment to make reasonable PCBs you may be better off using a [...]

By | June 8th, 2015|Notes|

How does SPI work?

3In a pervious post we mentioned Wingman27's Arduino Constant Current Dummy Load. A part of that Instructable worth its own post is Wingman27's videos explaining SPI. All the tutorial source code used in the videos can be found on Wingman27's Github page. I have built a programmable dummy load inspired by Daves initial one, I think it [...]

By | June 5th, 2015|Instructional, Notes|

Wi-Fi Connected E-Ink Display

This would make a nice remote data display. People implementing the Scrum Methodology for project management often record all their tasks on a big whiteboard. However, it’s useful to have up-to-date graphs to ensure projects are on track. [Sprite_TM] augmented the whiteboard by building an Wi-Fi connected E-Ink Display. Source: Wi-Fi Connected E-Ink Display | Hackaday

By | June 4th, 2015|Notes|

Arduino Constant Current Dummy Load

Check out this detailed constant current dumy load Instructable by Wingman27. It is a programmable Arduino-based instrument that allows the program a specific current to draw from a source. Wingman27 goes through the theory behind design his device enough that you'll take away a solid understanding. I'd love to see this with a programmable power curve to simulate [...]

By | June 3rd, 2015|Notes|

Low cost DC millivolt source

This DC millivolt source would be good for simulating thermocouples during product development and testing. How would you use it? DC millivolt sources are often used for thermocouple simulations, DMM, ADC and analog circuit calibrations and fault findings, etc. Most of the DC millivolt circuits are based on expensive (and sometimes hard to find) operation [...]

By | June 2nd, 2015|Notes|

How to Build a Thermocouple Amplifier

Hackday's Bil Herd explains things again with a great video detailing how to make a thermocouple amplifier. A Thermocouple is a terrific way to measure temperature. The effects of temperature change on dissimilar metals produces a measurable voltage. But to make that measurement you need an amplifier circuit designed for the thermocouple being used. Source: [...]

By | June 1st, 2015|Notes|

The cutest quartz crystal microbalance

This Arduino-based quartz crystal microbalance is capable of measuring forces down to 700 picograms. A wonderful design as well. The clever folks over at [Novaetech SRL] have unveiled openQCM, their open-source quartz crystal microbalance. A QCM measures very minute amounts of mass or mass variation using the piezoelectric properties of quartz crystal. When an object is [...]

By | May 31st, 2015|Notes|

3 Dollar Precision Frequency Standard

Paulie over at the EEVBlog made a great little lab frequency standard. Playing around with my new $10 Ebay frequency counter I noticed it was a few counts off from my old 10mhz reference dug up out of the toolbox. Specs for the oscillator claimed 1ppm/yr and it was coming up a bit outside that. [...]

By | May 30th, 2015|Notes|