January 2011 – Experimental Engineering

Posted on January 26, 2011 by The Engineer — 4 Comments

Audi TT Roof Hydraulics

This is the hydraulic system from an Audi TT that would power the soft top. Here is the hydraulic pump unit. Oil Tank is on the left. Power is 12v DC at ~20A

The pair of hydraulic cylinders that attached to the roof mechanism.

One of the cylinders has a limit switch built in. The brass bolt coming out of the side of the head is one contact. The other contact is the cylinder body.

Marking on the hoses. This is Parker Polyflex hydraulic hose. 1/8″ ID.

Drive motor for the hydraulic pump. Standard DC permanent magnet motor.

Motor power terminals & suppression capacitors. As the reversing relays actually short the motor out when de-energized, there is a lot of arcing at the brushes without some suppression.

Reversing relay stack. Each relay is a SPDT configuration. The pair are arranged as a DPDT bank to reverse the motor, depending on which relay is energized.

Detail of the oil tank showing the level markings.

Solenoid valve on top of the unit. This valve provides full pump pressure to the cylinders when energized.

Posted on January 20, 2011 by The Engineer — Leave a comment

532nm DPSS Module

A quick post documenting a DPSS laser module i salvaged from a disco scanner. Estimated output ~80mW

Connection to the 808nm pump diode on the back of the module. There is a protection diode soldered across the diode pins. (Not visible). Note heatsinking of the module.

Driver PCB. This module was originally 240v AC powered, with a transformer mounted on the PCB with a built in rectifier & filter capacitor. I converted it to 5v operation. Emission LED on PCB.

Output beam from the module.

Posted on January 20, 2011January 20, 2011 by The Engineer — Leave a comment

Here’s my prototype 455nm laser head, constructed from the front section of an Aixiz module threaded into a heatsink from an old ATX power supply. This sink has enough thermal mass for short 1W testing.

Connection to the laser diode at the back of the heatsink. Cable is heat shrink covered for strain relief, & hot glued to the sink for extra strain relief.

Looking down the beam, laser is under the camera. Operating around 1.2W here

Camera looking towards the laser. Again operating at ~1.2W output power.

Posted on January 20, 2011 by The Engineer — Leave a comment

Power Pack Regulator Update

To help make my system more efficient, a pair of switching regulators has been fitted, the one shown above is a Texas Instruments PTN78060 switchmode regulator module, which provides a 7.5v rail from the main 12v battery pack.

A Lot like the LM317 & similar linear regulators, these modules require a single program resistor to set the output voltage, but are much more efficient, around the 94% mark at the settings used here.

The 7.5v rail supplies the LM317 constant current circuit in the laser diode driver subsection. This increases efficiency by taking some voltage drop away from the LM317.

The 7.5v rail also provides power to this Texas Instruments PTH08000 switchmode regulator module, providing the 5v rail for the USB port power.

Posted on January 14, 2011 by The Engineer — Leave a comment

Portable Power Pack Charger

A quick update to my portable power pack, a mains charging port. Uses a universal DC barrel jack.

Connection to the battery. 1N4001 reverse protection diode under the blue heatshrink tubing. I used a surplus PC CD-ROM audio cable (grey lead). Seen here snaking behind the battery to the DC In Jack.

Posted on January 14, 2011 by The Engineer — Leave a comment

Uniden Stalker Radar Detector

An early speed radar detector from the early 90’s. Pictures showing the front of the unit with the option buttons.

Bottom of the unit showing label. Unlike the newer plastic detectors, the whole casing of this unit is cast aluminium.
Model Uniden Stalker RD-6000W.

PCB removed from the casing. Volume/power control on the left. Option tactile switches on the edge of the PCB, with the indicator LEDs. Power input jack on the right hand side of the PCB. Large aluminium can is the detector assembly, containing the detector diodes. Waveguide horn is at the top.

Shot down the waveguide, showing the detector diodes at the end.

Indicators on the front of the unit, X, K & Ka band detection LEDs on the left, Power & detection level (1-4) LEDs in centre. City (C) (Audio (A) & Mute (M) LEDs on the right.

Bottom of the PCB, showing detection logic. Piezo buzzer top left.

Custom Uniden CPU. Marking UC1465.

Posted on January 12, 2011 by The Engineer — Leave a comment

Laser Diode Driver

Connection

The parts arrived for my adjustable laser diode driver! Components here are an LM317K with heatsink, 100Ω 10-turn precision potentiometer, 15-turn counting dial & a 7-pin matching plug & socket.

Here is the schematic for the driver circuit. I have used a 7-pin socket for provisions for active cooling of bigger laser diodes. R1 sets the maximum current to the laser diode, while R2 is the power adjustment. This is all fed from the main 12v Ni-Cd pack built into the PSU. The LM317 is set up as a constant current source in this circuit.

Here the power adjust dial & the laser head connector have been installed in the front panel. Power is switched to the driver with the toggle switch to the right of the connector.

The LM317 installed on the rear panel of the PSU with it’s heatsink.

Connections to the regulator, the output is fully isolated from the heatsink & rear panel.

Posted on January 10, 2011January 21, 2011 by The Engineer — Leave a comment

Portable Power Supply

This is detailing my portable multi-purpose power pack of my own design. Here is an overview, mainly showing the 4Ah 12v Ni-Cd battery pack.

Panel Features – Bottom: Car cigar lighter socket, main power keyswitch. Top: LED toggle switch, provision for upcoming laser project, Red main Power LED, 7A circuit breaker.

Top: Toggle switch serving post terminals, USB Port.
Post terminals supply unregulated 12v for external gadgets. USB port is standard 5v regulated for charging phones, PDAs etc.
Bottom: Pair of XLR connectors for external LED lights. Switches on their right control power & the knob controls brightness.

Additions are being made to this all the time, the latest being a 2W laser diode driver. Update to come soon!

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

Fluval 203 Canister Filter

Here is an old fish tank external filter & a few pics of the insides.

Label on the front of the pump head. Fittings on either side of the motor are water I/O.

Underside of the pump head, inlet is on the right, outlet from the pump is on the left. Pump intake in centre.

Pump disassembled. This pump requires no shaft seals as the impeller is driven magnetically with a synchronous motor.

Filter stack removed from the unit. From left: foam media, activated charcoal/gravel & ceramic pellets.

Posted on January 5, 2011January 4, 2011 by The Engineer — Leave a comment

Bandridge VA-315

This is a small audio mixer, marketed for camcorder audio dubbing.

I/O Panel on the rear of the unit. Contains a small preamp, but will not drive speakers directly. Power is a 9v battery or plugpack.

Front of the PCB removed from the case. Mic preamp bottom right corner. Each channel has it’s own Preamp IC between the faders.

Rear of the PCB.

Posted on January 5, 2011January 3, 2011 by The Engineer — Leave a comment

Chicom “500W” ATX PSU

Here is a cheapo 500W rated ATX PSU that has totally borked itself, probably due to the unit NOT actually being capable of 500W. All 3 of the switching transistors were shorted, causing the ensuing carnage:

Here is the AC input to the PCB. Note the vapourised element inside the input fuse on the left. There is no PFC/filtering built into this supply, being as cheap as it is links have been installed in place of the RFI chokes.

Main filter capacitors & bridge rectifier diodes. PCB shows signs of excessive heating.

Filter capacitors have been removed from the PCB here, showing some cooked components. Resistor & diode next to the heatsink are the in the biasing network for the main switching transistors.

Heatsink has been removed, note the remaining pin from one of the switching transistors still attached to the PCB & not the transistor 🙂

Output side of the PSU, with heatsink removed. Main transformer on the right, transformers centre & left are the 5vSB transformer & feedback transformer.

Output side of the unit, filter capacitors, choke & rectifier diodes are visible here attached to their heatsink.

Comparator IC that deals with regulation of the outputs & overvoltage protection.

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 January 3, 2011 by The Engineer — Leave a comment

RTL8187B Linux Driver

Not strictly teardown related, but here is the Linux version of the RTL8187B WiFi chipset driver for all those who require it, it’s not available on the Realtek website:

http://www.experimental-engineering.co.uk/downloads/rtl8187B_linux_26.1056.1112.2009.release.tar.lzma

File is compressed with TAR.LZMA

Month: January 2011