pad – Experimental Engineering

Posted on March 22, 2017April 24, 2017 by The Engineer — Leave a comment

Philips LED PAR38 Lamp Teardown

These large LED Philips PAR38 lamps were recently on clearance sale in my local T.N. Robinsons electrical contractors for about £3, so I decided to grab one in the hopes I might be able to hack it into a low-voltage LED lamp. These are full-size PAR38 format, with most of the bulk being the large aluminium heatsink on the front. The back section with the power supply module is secured with silicone, so some unreasonable force was required to liberate the two pieces.

These lamps are rated at 18W in operation, and are surprisingly bright for this power level.

The front has the moulded multi-lens over the LEDs, to spread the light a bit further than the bare dies.

The LED array is two series strings of 4 LEDs, for ~24v forward voltage. Unusual for a high power LED array, this PCB isn’t aluminium cored, but 0.8mm FR4. Heat is transferred to the copper plane on the backside by the dozens of vias around the Luxeon Rebel LEDs. There is a thermal pad under the PCB for improved heat transfer to the machined surface of the heatsink.

The power supply & control PCB is pretty well made, it’s an isolated converter, so no nasty mains on the LED connections.

Posted on August 23, 2016August 15, 2016 by The Engineer — 1 Comment

Sony Watchman FD-20 Composite Video Hack

Hacking the Sony FD-20 to accept a composite input is easy – the tuner receives the RF transmission, produces an IF, this is then fed into IC201, a Mitsubishi M51364P Video IF Processor. The VIF IC then separates out the composite video signal, which is output on Pin 13 (in photo above, left side, 3rd pin from the top). The audio is separated out & sent via Pin 11 to the Audio IF processor.

In the above photo, the VIF IC has been removed from the board with hot air, as it was interfering with the signal if left in place. The RF tuner was also desoldered & removed. Unfortunately I managed to mangle a pad, which is the ground pin for the VIF IC. This isn’t much of an issue though, as an identical signal ground is available, just to the left of the IC.

The audio can be tapped into in a similar way, the circled pad in the centre of the photo marked SIF is the place, this is the output of the Audio IF processor to the audio amplifier. The Audio IF processor didn’t interfere with the injected signal, so it was left in place.

Posted on January 31, 2016January 30, 2016 by The Engineer — Leave a comment

Camping Gear – Optimus Nova Multifuel Stove

For as long as I can remember I’ve been using Trangia-type alcohol fuelled stoves when I go camping, even though these have served my needs well they’re very limited & tend to waste fuel. I did some looking around for Paraffin/Kerosene fuelled stoves instead, as I already have this fuel on site.
I found very good reviews on the Optimus Nova above, so I decided to go for this one.

This stove can run on many different fuel types, “white gas” (petrol without any vehicle additives) Diesel, Kerosene & Jet A.

Here’s the “hot end” of the device, the burner itself. This is made in two cast Brass sections, that are brazed together. The fuel jet can be just seen in the centre of the casting.

The fuel bottle is pressurised with a pump very similar to the ones used on Paraffin pressure lamps, so I’m used to this kind of setup. The fuel dip tube has a filter on the end to stop any munge gumming up the valves or the burner jet.

As with all liquid-fuelled vapour burners, it has to be preheated. There’s a fibreglass pad in the bottom of the burner for this, and can be soaked with any fuel of choice. The manual states to preheat with the fuel in the bottle, but as I’m using Paraffin, this would be very smoky indeed, so here it’s being preheated with a bit of Isopropanol.
The fuel bottle can be seen in the background as well, connected to the burner with a flexible hose. The main burner control valve is attached to the green handle bottom centre.

Once the preheating flame has burned down, the fuel valve can be opened, here’s the stove burning Paraffin on very low simmer. (An advantage over the older alcohol burners I’m used to – adjustable heat!)

Opening the control valve a couple of turns gives flamethrower mode. At full power, the burner is a little loud, but no louder than my usual Paraffin pressure lamps.

With a pan of water on the stove, the flame covers the entire base of the pan. Good for heat transfer. This stove was able to boil 1L of water from cold in 5 minutes. A little longer than the manual states, but that’s still much quicker than I’m used to!

The top of the burner opens for cleaning, here’s a look at the jet in the centre of the burner. The preheating pad can be seen below the brass casting.

Posted on February 6, 2011February 4, 2011 by The Engineer — Leave a comment

Window Break Alarm

Cheap unbranded window break alarm. Here is the front of the unit, with the sounder at the top, Power/sensitivity switch at the right. Battery test button at the left.

Rear of the device, with the adhesive pad used to attach it to a window.

Front cover removed, showing the batteries, PCB & the sounder.

PCB removed from the casing, showing the remaining components.

Posted on January 4, 2011January 3, 2011 by The Engineer — Leave a comment

PSP Slim

Here is a PSP Slim that recently died.

For those that are interested, here is the ID label, this is a PSP-2003.

Here the front of the unit has been removed, showing the first internal components.

Here is the unit with the LCD removed, here the mainboard is partially visible.

Left pad unit removed from the PSP, with the left speaker & the memory stick slot cover.

Rear of the left pad assembly, showing the speaker.

Joypad removed from the casing. Resistive unit.

Headphone/data board removed from the casing. This also has TV-Out on the PSP-200x series.

Mainboard removed. Main CPU is at the top. Sockets around the bottom connect to the UMD drive & UMD Drive.

Closeup of the main chipset. CPU is the top IC.

Rear of the mainboard, Memory Stick socket on the right.

Closeup of the WiFi chipset & the charging power socket on the right.

Closeup of the bettery connector & the charge controller IC.

UMD Drive removed from the rear of the casing. This is a miniature DVD style drive, using a 635nm visible red laser.

Rear of the UMD drive, showing the laser sled & drive motors. Both the spindle motor & the sled motor are 3-phase brushless type. The laser diode/photodiode array is at the top of the laser sled.

Posted on October 20, 2010 by The Engineer — 1 Comment

Co-Op Bank Card Reader

This is a little security measure you get with Internet Banking with the Co-Op, generates codes to confirm your identity using your bank card. About the size of a pocket calculator, this is the keypad & screen.

The rear of the unit, the card slots into the top, manufactured by Gemalto Digital Security.

Outer back cover removed, showing the 8 contacts for the chip on the bank card, the 2 contacts below that switch on power when a card is inserted. Power comes from 2 lithium coin cells in the compartment on the lower left.

PCB removed from the casing, showing the internal components. Two large pads at top left are battery connections, while the only IC on the board is the main CPU, under the card connector. 6MHz oscillator & 32Khz crystal on board for processing & timekeeping. LCD screen connection at far right.

Reverse side of the PCB, with the keypad contacts. LCD on right, with programming interface pads at side of keypad.