Mutchus

We described simple method, how to drive modellers servo. Today, we are going to try to drive this servo from potentiometer connected to TR module ADC. It is reaction to forum thread where is discussion about airplane model control possibility. [ ]

This circuit uses a 555 timer as the bases of the touch switch. You can learn more about 555 timers in the Learning section on my site. When the plate is touched the 555 timer is triggered and the output on pin 3 goes high turning on the LED and the buzzer for a certain period of time. The time that the LED and the buzzer is on is based on the values of the capacitor and resistor connected to pin 6 & 7. The 10M resistor on pin 2 causes the the circuit to be very sensitive to the touch. Touch Switch II Circuit Diagram

I don’t often build more than one of the same pedal. In fact, I think the only one I’ve ever built twice was the Minimixer (http://diystrat.blogspot.com/2008/08/two-channel-mini-mixer.html), but I don’t think that even counts as a pedal. Christian over at Black Sunshine Media was so enamoured with the Volumizer, however, that I offered to build one for him too. I also took the opportunity to do a better blog post about it, since at the time of doing the original one, I kind of skimmed over some important points. Firstly, some background. The Volumizer is my clone of an MXR Micro Amp, the schematic of which can be found at General Guitar Gadgets. There is basically no difference between my circuit and the one shown there, apart from the layout and possibly a couple of very slightly different parts (due to a lack of local availability). This pedal is a great little pre-amp, which boosts volume and nothing else. It’s nice and clean and only provides distortion if you use it to drive some...

About a year ago I came across an interesting article in Make Magazine about a guy who took his Fossil Wrist PDA and installed an Apple II emulator on it.   He was able to load many of the Apple II software titles and run them at regular speed.   The thought of having a fully functioning Apple computer on my wrist excited me enough to give it a try.      People that are attempting to do this should be familiar with the Palm OS as well as using jot or Graffiti 2 as an input method.   The Fossil Wrist PDA (now discontinued) features a tiny gray 160×160 pixel screen, the same number of pixels as most palm devices up to Palm III, with 16 shades of gray. The watch runs Palm OS 4.1 with its 66MHz processor and has a tiny stylus hidden in the watch clasp. It is able to carry out most PDA functions, and run any normal Palm OS-compatible application (up to 4.1). It features 8 Mb of RAM (about 7.7 Mb available to user) and 4 Mb of flash memory. Like other Palm OS de...

Among the many smaller jobs that have to be done to this vintage Hofner Colorama II is to flatten the warped plastic pickguard and rear tremolo cover. Here’s how they both looked before starting: Pickguard: Rear tremolo cover: I decided to tackle the rear tremolo cover first, since it appeared to be a much simpler job and also easier to replace should things go horribly wrong. I really couldn’t find any information about this on the Internet, so I did what seemed logical in my head, which was to sandwich the plastic in-between two panes of tempered glass, clamp the whole lot together, and heat it with a very hot hairdryer. Here’s the setup: After 10 or 15 minutes of heating the area above AND BELOW the cover, I took the top pane of glass off to confirm that the plastic had become soft, then clamped everything back in place and left it to cool naturally. Since I wasn’t in a hurry, I left it for 24 hours, although I’m sure that wasn’t necessary at all. The tremolo cover came out complete...

With this sound activated switch, control by sound may be very useful, not just on a robot but also for a bit of home automation, for example a sound-activated light responding to a knock on the door or a hand clap. The light will be automatically switched off after a few seconds. An alternative use is burglar protection — if someone wants to open the door or break something the light will come on, suggesting that someone’s at home. The circuit can work from any 5–12 VDC regulated power supply provided a relay with the suitable coil voltage is used. Sound activated switch circuit diagram When you first connect the supply voltage to the sound activated switch circuit, the relay will be energised because of the effect of capacitor C2. Allow a few seconds for the relay to be switched off. You can increase or decrease the ‘on’ period by changing the value of C2. A higher value results in a longer ‘on’ period, and vice versa. Do not use a value greater than 47μF. Biasing resistor R1 det...

The tremolo arm on our vintage Hofner Colorama II is supposed to be held on with a type of thumb wheel screw, but that’s obviously been lost at some stage and the remaining stud/screw had been hammered down to act like a rivet and hold the tremolo arm on, irreversibly damaging it (the stud) in the process: The tremolo unit has already been removed from the guitar, but can be disassembled further by removing the big screw holding the arm lever on: Here's what we're left with: I've previously drilled into the stud to remove the arm, and the remaining stud has to be unscrewed as it is completely destroyed. That can be forced out with a pair of mole grips (vise-grips), by turning it in an anti-clockwise (counter clockwise) direction: There's quite a bit of rust on both this part and the tremolo unit itself, so a wire brush is used to remove it: I'm also rounding the front end of the lever, since it was originally square in shape and was catching on and damaging the trem...