My name is Karel and I’m creating an open source temperature controller. Please see the FAQ for open source licenses. I initially started this project because I make my own prototype PCBs at home, using the toner transfer method, and found out the laminator I use, a Scotch TL-901, doesn’t run hot enough and it took several passes to get the board hot enough. Instead of taking the time to reverse engineer the control board that was in the laminator, I decided to make my own.
After I finished the first prototype, I quickly realized there could be a lot of uses other than controlling a laminator. Some that came to my mind included using the board to modify a window A/C to be used in a walk in cooler, measuring inside and outside temp to control a green house, using it to control an aquarium heater, or even controlling egg hatching. I’m sure there are lots of other uses that the open source community will find.
Open source temperature controller – [Link]
The STD32 offers the user the possibility to remotely switch ON or OFF electronic devices and to receive alarm messages via (SMS). You can switch devices either with an SMS or using a simple voicecall. Alarm messages (SMS) can be received with any mobile phone supporting SMS functionality.
With the new generation of the STD32 you now also have the possibility to receive alarm messages via e-mail. With the help of the digital camera which is available as an accessory, pictures can be taken and sent via e-mail triggered by an alarm.
The STD32 has an integrated webserver which allows direct access to the device via the internet and a standard webbrowser (e.g. Internet Explorer or Firefox) from a computer or a mobile phone with web functionality. Thus it is very simple to switch electrical devices remotely and to change the configuration of the STD32 from anywhere.
Simple GSM control
- New! Fixed IP address (in-built server)
- New! Camera interface (sends still images via email)
- Two alarm inputs, e.g. for movement, vibration, temperature or moisture sensors
- Two relay outputs, potential-free max. 6A/250V
- Alarms via text message
- Remote setting of parameters (on times, etc.) possible
- Five alarm addresses
- Basic functions can be activated by telephone with no call charge
- Online configuration via the internet
- Camera and built-in box available as accessories
- Supplemented with SIM cards
STD32IP Remote Controlling /Alarm for GSM Network – [Link]
“UPB communication is a method of reliably communicating command, control, and status information across an electrical AC powerline. Because of its low cost and high reliability characteristics, the UPB communication method is ideally suited for command and control applications in both the residential and commercial markets. “ – For further details please refer to UPB Description.
One of its disadvantages it has only widely spreaded in the US (120VAC 60Hz). This article focuses on the European (230VAC 50Hz) electrical network, but with a little firmware modification it is possible to adapt it to the US mains. The price of an UPB device is around $80-$100, with this article you can build it from ~$8.
Cloning the UPB home automation system – [Link]
With a powerful relay interface module Finder 48 series you can control devices reliably and digestedly directly from a distribution box.
Very often used centralized control of devices from a distribution box via relay interface modules offers several benefits. This solution enables for example a transparent and quick installation, simple functionality test and easy changes in configuration if necessary. To place switching elements to a DIN rail can in many cases substantially increase the immunity to disturbances. It is thanks to the fact, that when a relay interface module is placed in a distribution box near a controlling electronics, wires leading to the module are very short. By this we avoid parallel layout of control wires with other power-line wires, often few tens of meters long, from which a current able to switch on a relay could be inducted in extreme cases.
Advantages / Features:
- relay interface module for a DIN rail
- versions with 1 or 2 changeover contacts
- 8/16A 250V AC rated current
- 10*10E6 mechanical life
- ambient temperature range -40 to +70°C
- only 0.5W power consumption (DC versions)
- contains components for EMC coil suppression and indication status LED
- made in EU
Finder 48 are powerful relay interface modules in versions with one or two changeover contacts. They are available with a coil for DC or AC voltage as well as with screw or screwless terminals. From our stock we offer you 2 versions – 48.52 and 48.61 with a sensitive DC coil with only a 0.5 W power consumption. Interface modules already contain components protecting against wrong voltage polarity, for EMC suppression as well as indication circuit with a LED.
Besides high 16/8A switching currents offer Finder 48 also a high level of safety thanks to an up to 6 kV insulation voltage (coil/contacts). Finder 48 enable instant relay rejection by means of a plastic retaining clip, what makes an inspection or exchange of a relay easier. Also available is the jumper link for a mutual interconnection of several interface modules. Detailed information will provide you the Finder 48 datasheet.
Control devices from a DIN rail reliably and safely – [Link]
Giorgos Lazaridis writes:
If you have work with some kind of industrial or marine automation, then most probably you’ve heard before the term PID. PID controllers are very common in closed-loop systems today. Here is how this system can calculate and minimize the error with great precision.
The whole story began as a marine application, when people were trying to find ways to make reliable and accurate ship steering systems. But the problem was that, if the automation turns the rudder let’s say left, the ship will not turn instantaneously, instead it needs a long course, for ships do not steer like like cars, instead they have a big hysteresis. Another problem is also that when the ship finally turns to the right direction and the automation turns the rudder straight, the ship keeps turning left due to inertia and many other parameters like waves, wind, speed etc.
At first, proportional systems were developed to do this. A proportional systems reads the feedback (electronic compass) and turns the rudder according to the angle that the ship needs to turn. If for example the ship had to turn 45 degrees left, the rudder would turn 20 degrees, and as the ship slowly turns to this direction, the rudder decreases its angle proportionally. But this system has a great disadvantage: Either the rudder will oscillate left and right because the ship will never stay on course precisely due to external disturbances, or the system will stabilize with a small constant error in angle.
PID Theory – [Link]
Giorgos Lazaridis writes:
An AC Hum touch sensor is a very special technique, rarely used for switching applications, because it has a great disadvantage. In order to operate normally, an active AC power line has to be near by. More info about this type of touch sensor, along with other types (including the capacitance method), can be found in the corresponding theory page, how the touch buttons work..
DIY AC Hum Touch Button – [Link]
Giorgos Lazaridis writes:
Soldering stations comes in a variety of prices and capabilities. The cheaper stations have a power controller, to control the power delivered to the soldering iron. More expensive stations will have a temperature controller near the tip of the soldering iron, and control the temperature using this feedback.
The quality of soldering with a station is much higher than with a simple soldering iron. Especially if the station has a temperature controller on the tip. That is because, the solder has a very specific working temperature. For example, the one i use (60% tin 40% lead), is liquefied at 190C. Of course, you do not solder at 190C! The soldering iron i use, exceeds by far this temperature. I measured it up to 410C! This has negative effect on the soldering quality.
Homemade Soldering Station – [Link]
We’ve been working hard over the last several months to build a fully-featured, open source PID controller that’s every bit as capable as its closed brethren.
(If you’re so inclined, there’s also a post on my personal blog with some introductory videos)
osPID – Open Source PID Controller – [Link]
Ishan Karve writes:
I work in an office where working late in the night is the norm including weekends.. This post is not about my office or about the work we do late into the night but about a problem statement posed to me by my subordinates. It goes like this..
The office or rather the building rules demand that we shut down (hard off) all electrical equipment once the office is finally shut for the day. This means that our office servers also requires to be shut down along with the UPS (APC SMART 2200). Now this has nothing to do with our office trying to be green but more to do about obviating any fire risks.
So, whats the problem. The problem is that, once we (management) leave the office, the duty staff has to shut down all the equipment including the servers. The issue is that our two servers running WindoZe 2008 R2 and WindoZe 2003 take about 15 minutes to shut down cleanly. And the UPS then needs to be shutdown afterwards. 15 minutes may seem a small time interval for an office which works routinely for 15+ hours in a day in a single shifts 7 days a week. But at night 2330 when its time to go home every minute looks like an hour to the subordinate staff. So the problem was narrated to me over a short tea break. Since I believe in working Smarter and not Harder, I decided to save 15 man minutes every day.
APC UPS Shutdown Manager – [Link]
For use with my home theater PC I developed an IR Transceiver by combining 2 projects (Receiver, Blaster). Note that this device may be taxing of your serial port, I take no responsibility for any damage you cause to your equipment. That said, I’ve provided PDF’s of the silkscreen, copper layout, and the Eagle PCB files.
IR Remote Control Transceiver- [Link]