23 Mar 2018

Extech CO250 Protocol Details

Extech CO250 Protocol Title

Note: This post is currently just some loose notes during my R&D, and is a continuation of the Extech CO250 project. See my Extech CO250 review here. I have RS-232 details and teardown here. Open-source Java library I have a working Java library that reads all values over serial and provides statistics (minimum, maximum, average, […]

22 Mar 2018

Extech CO250 RS-232 details

Extech CO250 Title

The Extech CO250 (AKA Senseair pSENSE RH) is a relatively cheap handheld air quality measurement device with decent features. It measures carbon dioxide (CO2), dry-bulb temperature, and relative humidity, and also provides calculated dew-point and wet-bulb temperatures. One interesting feature, and the subject of this post, is it’s serial communications port. It comes with a […]

21 Mar 2018

Extech CO250 Review

Extech CO250 Kit 2

The Extech CO250 is a relatively cheap handheld air quality measurement device with decent features. It measures carbon dioxide (CO2), dry-bulb temperature, and relative humidity, and also provides calculated dew-point and wet bulb temperatures. After some searching I found what seems to be the OEM device which Extech rebadges. The original device seems to be […]

18 Apr 2016

Sanden PET-07 Power Supply RS-232 Module Reverse Engineering – Part 2

Sanden Title 2

In this video we take another look at the RS-232 plug-in module for the Sanden PET-07 CC/CV power supply. In particular, we see how the voltage output can be controlled and how this clears up some ambiguity with the circuit design. In part three, we will *finally* attempt to communicate using RS-232 to monitor and […]

10 Apr 2016

Sanden PET-07 Power Supply RS-232 Module Reverse Engineering – Part 1

Sanden Title 1

In this video we take a look at the Sanden PET-07 CC/CV power supply. In particular we look at the RS-232 plug-in module and attempt to make sense of the signals between the main board and plug-in board. In part two, we’ll apply this knowledge to attempt to receive RS-232 data from the power supply. […]

30 May 2015

Protek 608 RS-232 details

Protek 608 RS-232 login analyser

This is following on from my previous post introducing the Protek 608 multimeter and my software project. In this post I detail the communications hardware, an important consideration for future development. The Protek 608 uses an RS-232 connection to allow for interfacing with a PC. This is a very common connection that most DMMs used. […]

30 Mar 2015

Protek 608 multimeter overview

Protek 608 multimeter

The Protek 608 is a 5000 count digital multimeter made by Hung Chang, who have since changed their name to GS Instruments. I’ve owned one of these since about 2009. This multimeter is now discontinued and no longer available new, although they occasionally show up on the second-hand market from forums and eBay. This DMM […]

15 Nov 2010

Automatically connect to VPN at Windows startup

VPN connection

I use VPN for work quite often, and lately more often than not.  I found that some programs that load on Windows startup and rely on this connectivity were trying to connect before I had a chance to establish a VPN connection.  I needed a way to connect to VPN as soon as possible, even […]