A part of a bigger project needed control circuits for up to 16 DC solenoids. Instead of wiring up a one-off prototype, I decided to design and manufacture a PCB to do the job in a scalable manner, and with a minimum of Arduino pins, so that the same circuits could be used for future high power on/off control tasks.Continue reading “Solenoid Driver PCB”
The MPS020N0040D pressure sensor is a cheap component readily available for purchase on sites like eBay.
I recently needed to create a blow activated switch and, as I already had a few of these at hand, decided to design a minimal circuit that would provide a digital output when a threshold pressure was detected by the sensor.Continue reading “MPS020N0040D Sensor as a Pressure Activated Switch”
In some upcoming projects I intend to embed some processing intelligence into small devices. The smaller Arduino boards are too big and expensive for these applications.
After some investigation, I settled on using the ATTiny series of 8 pin microcontrollers. These processors vary in capability (from a very low end) and all provide 6 I/O ports. Tools compatible with the Arduino ecosystem are also available.
As a first step, I designed a small breakout board for the SOP8 version of these MCUs.
In Part 1 we looked at the design and hardware for the Soldering Station. This part covers the software, assembly and calibration of the system to provide accurate and reliable temperature control.
After many years persevering with a ‘simple’ soldering iron, I acquired a temperature controlled iron and was amazed at the difference it made to the quality of my work. Recently the iron failed and, although I managed to find the fault and repair it (the temperature sensor wire had broken off), it made me realize that I should keep one as a spare. It is actually quite difficult to repair an iron without an iron!
As I can’t afford to buy an expensive piece of equipment ‘just in case’, I decided to use this as an excuse for a hardware and software project based around a Hakko-FX888 soldering handpiece that I had already purchased.
One of the downsides of home-made CNC printed circuit boards is that a lot of the copper cladding remains and can lead to short circuits when solder strays onto the common waste area outside the formed tracks. Also, after a while it tarnishes and does not look great.
One solution to both these problems is to apply a solder mask over everything that is not meant to have solder on it, similar to professionally made boards.
Switching ‘buck converter’ power supply modules are fantastic, efficient, and can be bought for a few dollars (if not cents!). One drawback for me is that sometimes I need to have both positive and negative voltage supplies, and the buck converter/wall wart combination is not easily adapted to suit.
For these situations I have developed a reusable basic design using the LM317/LM337 3-Terminal Adjustable Voltage Regulators. Continue reading “Dual Voltage Power Supply”
For various reasons, digital I/O pins are always at a premium when implementing micro controller projects. There have been various multiplexing schemes described to allow more than one switch to be connected to a small number of pins, but some time ago I came across a very simple but highly scalable method that uses the 4017 decade counter to connect many switches (more than 100 if needed) to just 3 digital inputs.
With all the preparations completed, Umote can finally take shape for this application. The final product can be broken down into four major subsystems that need to be made and integrated in their final form – IR interface hardware, Enclosure, Power Supply, and Switches and Control Wiring.