January 18, 2021

Milling Aluminum Enclosure Lids, Pt2

First prototype of a work holding tool, in this case the base plate, for milling a set of off the shelf cases from Hammond Mfg (1455 series). This is done on a scrap of 1/4" 6061, about 8x6" (its an off cut scrap). The intent is to use a piece of MIC6 tooling cast aluminum. The bulk of the work was done with a 1/4" 3-flute 38 degree aluminum end mill. Read more

January 17, 2021

TopOff Minder

A quick little project as a spin-off of a larger common shared design for an aquarium controller, I’ve knocked together a small inlet sensor and 12V driver with 4 channels, allowing you to hookup a float switch or attach a DC pump across all four channels. Programming is handled by USB, or a CAN bus attachment. It shares a common CPU design and firmware build with my upcoming Reef-Pi controller and power bar, just dramatically simplified and providing a simple, safe DC output option. Read more

January 16, 2021

Freshwater LED, Pt1

Small design vignette for an LED driver design for freshwater LED lighting. In this example I’m using a 28 Yuji 5038 LEDs at 6500k and 98+ CRI. Since they are all in series, it offers about 100Vf, which is out of range for most of my LED drivers. However, it only needs 150mA maximum current, so becomes a tractable problem. Fitting in a 50x80mm space small case, this LED driver + controller uses some totally over-kill CPU (ATSAME51J20) featuring CAN, USB and dimming control, with a battery for RTC backup. Read more

January 16, 2021

Milling Aluminum Enclosure Lids

Just a small vignette on the milling of a Hammond Aluminum Extrusion case cap. All I have is a CNC6040 based machine with a 2.2kW spindle, but it would probably serve the purposes fine as we’re not chewing through a lot of metal.

September 18, 2020

Design Log: blueAcro Power Bar and Sensor Updates

Some updates for products over at blueacro.com - mirroed from Reef2Reef I have basic power boards already designed up, and a few sample cases in house. The form-factor is nice, though slightly tall compared to your average power strip. Probably not a major issue, as its a fair bit less wide. I’ll report back when I have some first samples assembled. The power board has a number of provisions, including protection for the relay contacts with inductive loads, without using a plain MOV or other circuit which leaks power. Read more

April 8, 2020

theatrus' Perfect Temperature Controller - Temperature Sensors

Let’s talk temperature sensors, at least let’s talk about the guts of a temperature sensor and less about the housing, cables, etc. There are three main varieties you’ll find in your typical “probe” style sensor, and a fourth I’ll mention because its common for integrated circuits. I’m considering “relevant reefing temperatures” to be about 75F to 83F - sorry, I haven’t switched to metric on temperature just yet, even though I reference them below. Read more

April 8, 2020

theatrus' Perfect Temperature Controller - The Overview

I’ve been keeping aquariums of all flavors for a very long time, and have seen and first hand experienced what happens when our lovable basic heaters (and chillers) run amok and fail to do their jobs correctly. Even worse, we often decide to go whole hog into the aquarium controller systems, which promise us web graphs and e-mails, while also being in charge of critical functions such as temperature and top-off, mixing software and control domains that should never be mixed (e. Read more

November 17, 2018

PurpleAir Sensor Investigation and Teardown, Pt1

With the ongoing poor air quality all over Central California due to the Camp Fire, the interest of providing fine grained and reliable air pollution measurements peaked. One of the interesting providers of data is the website PurpleAir.com. The data for PurpleAir is sourced from a series of sensors sold through the website

February 20, 2018

Parts Roundup: FemtoFET

Ever felt like your board level MOSFETs were too large? Texas Instruments now has an answer! Measuring in it as small as 0.7mm x 0.6mm, these FETs are small for board, but most importantly retain a sane PCB layout: the gate is actually at one end! No more squishing a layout where the gate has to trapeze through either of the high current paths, now you can more easily use two layer boards where all of the control signals to the FET are kept on the logical end of the device and nearer the MCU or other controller. Read more

March 31, 2017

Simple CO2 Solenoid Carbon Doser Project

Controlling pressurized carbon dioxide (CO2) delivery into a Calcium reactor or into a planted tank with precision can be fraught with problems. The conventional mechanism is to use a needle valve after a pressure regulator - this design is very finicky to adjust for low flow rates and has a tendency to drift over time, meaning your carefully controlled delivery is now out of whack. In addition, if you use a pH controller driving an AC solenoid valve, the valve actuation can be quite audible. Read more

© 2020 Yann Ramin