Bench Power Supply Build – Part II

This is the second post on my power supply build – also see part I and the Circuitmaker project page.  The aim of this project is to design and build a linear bench power supply with adjustable current and voltage and up to 2.5A output from 0-30V.

After building and testing the first version of the board I discovered a couple of issues. Most of the basic functionality worked – the voltage control, digital display, transformer tap select, etc. However, the current limiting never worked properly, there were some noise/oscillation issues and a couple of mechanical problems. So, Rev.1.1 was born which has now been tested and seems to be working nicely.

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Temperature Logger

I have finally finished my temperature monitor and logging module, originally designed to monitor beer temperature as it is fermenting (beer, fridge and ambient temperatures). It is an Arduino-based device which measures and displays temperatures from multiple attached temperature probes and logs them to an SD card . This is an old project from last year sometime which has been sitting 95% complete, just waiting on an enclosure and some finishing touches to the code. I posted a separate post about the enclosure design and 3D print, read it here.

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Designing a 3D printed electronics enclosure

This will be a quick post about the design and 3D printing of a custom enclosure for a temperature logger (see full writeup here) – a project which has been sitting on my table 90% finished for about a year now. I always find the enclosure to be the most time consuming and least interesting part of any project. As such an unfortunately high number of them stall at this final stage. 3D printing a custom enclosure is a much more interesting and attractive alternative to my usual approach of attacking a jiffy box with a drill and hacksaw.

The box needs to hold a board roughly 90x50mm, have a slot for an SD card, 3 temperature probe input connectors, a DC jack power input, a 16×2 character LCD and 3 pushbuttons. The design was all done in Autodesk Fusion (see my previous post) and printed on my Printrbot 3D printer (see my previous post). There were several iterations and test prints along the way to check sizing and tolerances and to test out some different designs. The final design can be found on my Autodesk account here.

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Sichuan Saison: Mark II

So I’ve been going through a nostalgia period with my brewing, and this week it was time to make another go of my Sichuan Saison. Last time, I’d used a White Labs yeast (no. 565). This time round I decided to keep it simple with a Wyeast Belle Saison packet. There were a few other changes I decided to make, here and there. One was the addition of Candy sugar, to make it have a little more kick. Another was the use of a Light malt, rather than a pilsener malt extract, lending it a little more body.


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Servo Motor Control with Mojo FPGA board

This post is part of my series on building a kinetic sculpture with the Mojo  FPGA development board. (Part1 Part2)

My Mojo development board finally turned up and so I’ve been playing around with it for the last week. This post  is just a quick update of some fist test code to control some servo motors and sweep them back and forth. The end goal of this project is full independent control of multiple servos to create moving sculptures. See this post for an overview of the project.

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A light sour for summer…

A few months ago, I found myself with some old light malt extract, about 200g worth, and some sour yeast I had been gradually building up from the first sour in a conical flask on my desk. I also had a Growler courtesy of Dave, who had brought back a nice DIPA from Aeronaut brewing in the USA. Naturally, all these came together in the for of a sour beer, which turned out to be deliciously light and refreshing. Unfortunately, I didn’t bother to write down any real details of the light sour recipe, rather it existed as an ephemeral idea in the back of my head; low on hops, high on bugs, sufficiently light to quench your thirst on long hot Sydney summer.

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Printrbot 3D Printer

After returning from a trip to the maker faire in San Francisco last year I felt like I needed to get involved and buy myself a 3D printer. After some research I settled on the printrbot simple metal. It seems like a solid mid-entry level printer which is easy to get started with and with fairly good support. I went with the kit form with the heated stage option which costs US$749. All up including shipping it ended up costing me about $1100AUD delivered.

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The tower of sour…

Having had a few weeks in the bucket to ferment, my dearly beloved hard as fuck IPA was ready for a few more weeks without the copious hop dregs sitting at the bottom. All looked well, with a delicious hoppy aroma when I cracked the top of the fermenter. All that remained was to move said IPA to the glass demijohns where my sour had been quietly turning delicious. This proved to be an opportunity for both the bottling of the Sour, and the second stage of fermentation for the IPA. All of this reminded me that I hadn’t provided a post for our successful souring, so I’ll go over that first.

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Mojo FPGA development board

This post is part of my series on building a kinetic sculpture with the Mojo  FPGA development board. (Part1 Part2)

Back at uni I did a course on digital logic design (COMP3222 for anyone interested) and really enjoyed it – it was one of my favourite classes. But for some reason I never followed up on it or did any more. I think part of the reason is the relatively large cost and complexity of FPGAs compared with microcontrollers. Anyone can buy an Arduino for a few dollars and get started pretty much immediately. Not so for an FPGA. In order to pick up where I left of at uni I’ve ordered myself a mojo board and plan to start getting back into some FPGA development.

Mojo FPGA dev board
Mojo FPGA dev board

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Bench power supply build – part I

This is the first post on my power supply build. Also see part II and the Circuitmaker project page.

An adjustable bench power supply has been on my list of things to build for quite a while. A linear supply should be relatively simple to design, with the added bonus of being a useful thing to have around. My goals with this project are to design and build a slightly more complex system than I have in the past, to lean to use PCB layout software and to actually get a PCB designed and manufactured. I wanted to design it from scratch, rather than using an adjustable 3 terminal regulator or a controller chip with everything built in – this is supposed to be a learning experience more than anything else.

My requirements are:

  • 0-30V adjustable voltage
  • 0-2A with current limiting.
  • Separate fixed 5V output for powering digital circuits.

Continue reading Bench power supply build – part I