A while back I found myself in the need of an adjustable RF attenuator capable of high-GHz operation. As luck would have it I had an old Spectrum analyser on the shelf at work, which we had retired quite some time ago. Spectrum analysers being quite capable test instruments, I
Trolley Propulsion System: Wheelchair Motor Units So it’s time to get the propulsion system underway for the trolley, a pair of wheelchair motors were sourced for this, from HacMan. Since I don’t know how many hours are on these units, or how they’ve been treated in the past, I’m going
Here’s another piece of commercial gear, from an industrial air conditioning unit. These pumps are used to drain the condensate from the evaporator unit, so water doesn’t end up raining down from the ceiling. This is a peristaltic pump, with a silicone hose forming the pumping element. The test switch
Description and Schematic SG-HM2 is a modular He-Ne laser power supply based on IC-HI1 with some minor enhancements. The first version is for laser tubes up to approximately 1 mW (2 mW with trivial modifications) but it should be straightforward to go to 5 mW or even higher power tubes
Effects of Magnetic Fields on He-Ne Laser Operation If you open the case on a higher power (and longer) He-Ne laser head or one that is designed with an emphasis on precision and stability, you may find a series of magnets or electromagnetic coils in various locations in close proximity
These units are used to broadcast local audio, such as from a public address system or local microphone. They accomplish this by producing a modulated magnetic field that a hearing aid is capable of picking up. Not many controls on this bit of equipment. A bi-colour LED for status indications,
With a recent order from a Chinese seller on eBay, this little gadget was included in the package as a freebie: I’ve not smoked for a long time, so I’m not too sure what use I’m going to find for this device, but it’s an electronic lighter! Pushing the slider
This is the Velleman MK179 Proximity Card Reader, which is supplied in kit form. In the image above you can see the completed kit, the read coil is etched onto the black PCB on the left. Bringing a recognised card close to the coil operates the relay on the main
Here are the viewfinder electronics from a 1984 Hitachi VHS Movie VM-1200E Camcorder. These small CRT based displays accept composite video as input, plus 5-12v DC for power. Here is the front face of the CRT, diameter is 0.5″. Closeup view of the PCB, there are several adjustments & a
Here is a Inductive charger designed for the Nintendo DSi. Cheap Chinese build, but it does work! Top has been removed from the unit here. Most prominent in the centre is a solid steel bar, simply there to give the device some weight. Pair of Tri-colour LEDs at the front
An old IDE interface Zip drive. This fits in a standard 3.5″ bay. Top cover removed from the drive, IDE & power interfaces at the top, in centre is the eject solenoid assembly & the head assembly. Bottom is the spindle drive motor. Head assembly with the top magnet removed.
This is an old cordless landline phone, with dead handset batteries. Here’s the handset with the back removed. Shown is the radio TX/RX board, underneath is the keyboard PCB with the speaker & mic. All the FM radio tuning coils are visible & a LT450GW electromechanical filter. Radio PCB removed
This is a 1500W hairdryer, death caused by thermal switch failure. This is the switch unit. Attached are two suppression capacitors & a blocking diode. Cold switch is on right. Heating element unit removed from housing. Coils of Nichrome wire heat the air passing through the dryer. Fan unit is
This is the Current Cost CC128 Real Time Power Meter. Shown here is the display unit, British Gas issued these free to some customers. This unit measures current power draw in Watts, cost of power currently being used (requires unit price to be set), overall kWh usage over the past
This is a Western Digital drive recently removed from my laptop when it died of a severe head crash. Top of drive can be seen here. Here the cover has been removed from the drive, showing the platter, head arm & magnet. Yellow piece top left is head parking ramp.