New Toy!

Today, my wife’s surprise for me arrived. I had NO idea what it was … she kept telling me that I’d love it and that it was something that we had spoken about previously.

Turns out, she was dead right … I love it!

My surprise was a USB Digital Microscope (50x optical 200x digital magnification).

My eyesight has been getting poorer over the last couple of years and I’ve been getting more and more into wanting to solder SMD … in fact general soldering was only happening because of my 20x desk lamp/mag. It seems that, as my interest/need for closer and finer work has increased, my eyesight has degraded correspondingly, ah the joys of getting older.

The stand that comes with the device is nice, but not that practical. The first thing that I did was take the magnifying glass off one of my “Third Hand” tools and mount the microscope on that.

That lifts the scope end of the device up by about 10 cm, giving me enough room under the scope to actually work.

Next, I played with the software that comes with the scope. It’s pretty simple to use, but it has enough functionality to make it very useful.

Now I can …

look at components on an Arduino clone and identify them.

look at my SMD components in their packaging (and identify them)

some NE555 SMD

0805 2N2222 transistors

0805 Super bright White LED

Identify Diodes

IN4148

See the colours of resistors … although, I’m still colour-blind. I’m still taking it on faith that these are 10Ω resistors

One day, I’ll write some software to identify the resistor by colour … ‘till then, I’ll use my multimeter for that.

Look at some of my soldering work and identify the IC type

 

As well as inspect my soldering and printed circuit boards

Overall, I am very happy with my present … now I need to set it up on the laptop on my electronics workbench. I probably also need to make a better stand for it. I’ve got a mini camera tripod, maybe I can make an adaptor for the attachment … hmmm … gears are whirring in my head.

AC Adaptor Power Supply – Recycle

NOTE: This project was a bit of a failure … I’m redoing this project using an LM317 instead of just using a POT to try to adjust the power. If you follow this project, you will only end up with a pretty circuit that doesn’t do anything very useful.

CAUTION: Modification of AC Power Adaptors is potentially dangerous. Read the specifications on the adaptor and observe output and polarity. Mistakes with AC Power can kill you. If you are unsure of the specifications of the adaptor that you are tinkering with … throw it away and get one that you know. Do not do ANY soldering on the adaptor or it’s cable when the adaptor is plugged in. I take NO responsibility for your safety, that’s your job.

In my previous article on power supplies for electrolytic etching I made use of an old AC Adaptor (wall wart) to provide power via a switch and potentiometer to an anode and cathode used in a simple circuit to an electrolytic etching bath. The adaptor recycle can be used for other purposes, and in fact I made a polystyrene hot-wire cutter using this same circuit. Now that I’ve used the project in a couple of different “tools” I suppose that it’s time to revisit the design and see what can be improved or changed.

My new application for this project is in a tool that will be used to bend acrylic sheet. There are a couple of interesting articles that can be found on various sites scattered across the interweb. I’m not going to list any here, they change too often. You can look at sites like lifehack and instructables for some pretty good examples of polystyrene cutters. The power supply is really what I’m interested in, so I’m going to focus on that for now.

Essentially, the AC Adaptor power is passed through a circuit adding a switch to make it easier to turn the power on and off, and through a suitably resistant potentiometer to allow the user to adjust the output power, effectively controlling the heating element (or in the case of the electrolytic etcher, the copper electrolysis anode). It’s also a good idea to install a power indicator in the circuit to improve safety (a visual indicator that there is current passing through the circuits output terminals.

So, in my case, I’m using this supply for three tools and two different types.

• Heat:
  • Polystyrene Hot Cutter;
  • Acrylic Heat Bender; and
• Current:
  • Electrolytic Etcher

So there is some versatility in the simple circuit.

The circuit above has two two pin screw terminal posts. The left-hand side is where the AC Adaptor will be connected to the circuit and the right-hand side is where the power will be output.

There are 6 parts (well 7 if you include the circuit board):

• 2 x 2 pin screw terminals;
• 1 x Red LED;
• 1 x 220Ω resistor;
• 1 x SPDT switch;
• 1 x B 10kΩ potentiometer (the resistance value of the pot should be increased to 100kΩ if you are using adaptors between >9 and 16V, I’m using a 9V adaptor, so 10kΩ … larger than that and you should probably not be using the adaptor at all).

I have connected the input power to a SPDT switch. This is where we turn the power to the output off. Of course, the power to the circuit is still live, you need to turn the wall socket off to completely power the circuit off.

The 3rd leg of the SPDT connects to the power indicator LED, which is connected to ground via a 220 ohm resistor. Additionally, the 3rd leg of the SPDT connects to the Power (leg 3) of the B10K potentiometer. The Wiper (leg 2) of the B10K potentiometer connects to the positive output terminal.

The negative input terminal connects to the resistor of the power indicator LED (as mentioned previously) and to the negative output terminal.

Connecting the load anode/cathode is done via the output terminal. I have a couple of banana plug to alligator clip connectors that I use, but bare wire end to spade connectors or any other appropriate connectors should be OK.

This is a good project candidate for mounting in a project box. I’m planning on bending some acrylic sheet to make the project box for this circuit … or you could make a pretty one by adding an instrument panel like my Steam Punk themed Electrolytic Etcher panel.

Enter the Christmas Break

Well, I really haven’t done much over the past month. I’m off on a Christmas break, so I’m unlikely to do much until the new year.

I hope that everyone who has been following my rants, experiments and general fiddling has a great holiday period and that you all stay safe.

I’ll be moving house (again) when I get back from my break, I hope that the new place has more space for me to experiment and fiddle. My current flat is tiny.