Derek Wolfe writes:
This circuit allows a simple switch or a low voltage pulse (5V for example) to control a large dc load. There’s a good explanation of MOSFET transistors and how to use them as a switch here. This is great for connecting a large load to a microcontroller or other logic circuit. Power MOSFET transistors are perfect for this application and can handle high voltage and current (100V, 77A for the NTP6411). This design would be able to power almost any load you can think of (probably even your car).
N-Ch Power MOSFET Switch - [Link]
Sorry for the lack of photos in this article, but we didn’t think about it being worth reporting until after it had all happened. Infact, we were concerned about retaining any evidence of the events. Inspired by the many toaster-oven reflow projects floating around the Internet, we set out to acquire the power to solder all those tiny SMD components ourselves. Toaster ovens aren’t that common in the UK and we were aiming for the lowest cost possible, so we hit ebay in search of a bargain. A very cheap Black and Decker Toast-R-Oven was on offer. The description was “only used a few times”, and the grainy photos showed an indeterminate “foreign” plug with an adaptor. Now, we aren’t generally in the habit of assuming that “some bloke on ebay” must know what he’s doing with electricals, but with the auction starting at £5 (and not going up a huge amount from there by the end) it seemed like a good idea.
Engineering of a reflow oven controller - [Link]
My parents growing their own organic food and they asked me to deal with winter temperatures problem in the storage room. It gets really cold here, in Ukraine. Some winters have even lower temperatures than -30°C (-22°F). So right now I designing a simple thermostat for keeping temperature at about 5-7 degrees C above zero. Plus right now I started to use my garage as a gym, so this thermostat would be handy there too.
ATtiny2313 Based Thermostat - [Link]
In this project we introduce easy to build, miniature servo controller. This miniature servo controller system is ideal for most of the robotic and mechanical projects. Some of the most notable key features of this project are:
- Tiny PCB design (35mm × 33mm aprox.) using standard through-hole components.
- Support for both analog and digital control interfaces.
- Compatible with most of the servo units.
- Low cost due to small amount of components.
Mini PIC12F675 Servo Controller - [Link]
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]