Getting into microwave but having problems finding an accurate method of measuring the RF power at these frequencies? If you are like me, you can’t afford to buy even a used HP 432, 435 or 436 version power meter via eBay. I have to admit I was tempted recently when I spotted a HP435A listed for here in Australia and then noted that there was no sensor with it. Quite a while later after searching eBay for sensors, I came away for a reality check – I might get the 435A for under $200 but a suitable sensor was going to cost somewhat more than $300. Sorry, but $500 doesn’t figure into my budget for a device which might be up to 40 years old, with calibration status unknown and sensor status questionable – and expensive to repair if damaged.
DIY Microwave RF Power Meter – 100MHz – 12GHz - [Link]
They say you are only as good as your tools. This is a statement I can vouch for, as better tools can make the difference between a sleek and well designed prototype and a rats nest covered breadboard. Unfortunately as an electronic hobbyist you don’t always have the budget of a big tech company at your disposal. But hey, that’s what DIY projects are for!
Starting off as a hobbyist or even small tech company designing and building electronics you will soon learn that most of the fun IC or MCU chips are either cheaper in, or only available in, surface mount form, and fancy reflow ovens are expensive. But a soldering oven isn’t much different from a toaster oven– the only difference is the accuracy and temperature settings.
That is why I’m going to show you how to build your very own Soldering Reflow Oven for under $100 from an old/new standard toaster oven, thermocouple and a microcontroller.
DIY Soldering Reflow Oven - [Link]
This is not really an app note, but more of a tutorial on DIY op-amp based linear regulators. The article describes the basics of op-amp regulator, and includes schematics and in-depth explanations of how the various circuits work. [via]
This article follows the history of a popular series of DIY linear regulators. Starting from initial concepts basically idential to the archetype block diagram above, this particular thread through history will wind up in a very sophisticated design. Because this final design developed piecemeal over the course of two decades, that’s how I’ll show it. I think showing the steps this series of designs went through aids understanding of the final design.
Op-amp based DIY linear voltage regulators - [Link]
Eric Mack writes:
This DIY cell phone created at MIT manages to have something for just about every major contemporary subculture or hipster subset I can think of.
Nerds and tinkerers? Check. Wooden case for the steampunk set? Check. Huge antenna for the retro, skinny-jeans-wearing set? Check. Big buttons for the fat-thumbed and Luddite crowd? Check. Rugged design for outdoorsy types? Check.
The folks at the MIT Media Lab created this prototype with an SM5100B GSM Module that takes a standard SIM card and a custom circuit board. The screen will take you back to the last century at 160×128 pixels and the laser cut wood and veneer enclosure is just one of many possible exteriors, given the availability of 3D printing. While far from a smartphone, voice, texting, and other slightly old-school functionality is possible. All told, the parts cost between $100 and $150.
Awesome DIY cell phone has universal appeal - [Link]
Retromaster has honed his PCB making skills to get professional quality boards at home. He’s successfully made double sided PCBs with 8 mil trace width, with 6 mil clearance. In his guide he describes how to etch the PCB with toner transfer, how to use mechanical vias, and hot to apply soldermask paint.
DIY double sided PCB with soldermask - [Link]
Please welcome ArduPilotMega 2.0! – DIY Drones. Jordi writes – [via]
APM 2.0 is the culmination of almost a year of hard work. We wanted to make it perfect and we finally have it, we are pushing the limits of AVR and Arduino. I’m sure you will love it, and it’s designed to cover all the DIY community expectations (including those that are not so DIY and are only interested for something that doesn’t require soldering skills).
ArduPilotMega 2.0! - [Link]
Lawn Sprinkler the Introduction Part 1. Mike writes… [via]
The new craze for Home Automation is to use technology to Go Green. One aspect of Going Green is about managing resources in a more efficient way. I have seen a number of other hobbyists build projects that manage the amount of electricity or gas that they use within their home. In this project I am going to manage the amount of water I use for watering my lawn. In part 1 of this series I am going to cover the big picture of what I am attempting to do.
DIY sprinkler system with Netduino Plus - [Link]
Teravolt.org – DIY High Voltage Capacitors… [via]
Sure making a cap out of paper is fun and all, but making a high voltage one is even more fun!
You don’t need lots of money to make high voltage capacitors, in fact some pretty decent ones can be made with some cheap and readily available materials. This is because capacitors are very simple devices; consisting only of a dielectric and two plates. Most often a capacitor’s plates are just aluminum foil, and reynold’s wrap is easy enough to obtain, but what about the dielectric?
Enter the overhead projector sheet. Transparencies as they are commonly known as are nothing but acetate film, and while this is not the ideal dielectric for a capacitor it still does quite a good job. Typically a four mil OHP sheet can withstand 14kV before breaking down. As for obtaining them, the cheapest I have found these sheets is $10 for a box of 100, enough for about 16 capacitors.
How you make the capacitors is a rather trivial task, all that needs to be done is some cutting, flattening and rolling. Below I have an image that explains the process. Multiple sheets of OHP sheet are used to increase the capacitor’s voltage rating, and two sets of sheets are used so the capacitor can be rolled up.
DIY High Voltage Capacitors – [Link]