Here is an AVR powered optical tachometer design, that I adapted from the schematic found here.
I made a couple of changes to the circuit & designed a PCB & power supply module to be built in. The original design specified a surface mount IR LED/Photodiode pair, however my adjustment includes a larger IR reflectance sensor built onto the edge of the board, along with a Molex connector & a switch to select an externally mounted sensor instead of the onboard one.
There is also an onboard LM7805 based power supply, designed with a PCB mount PP3 battery box.
The power supply can also be protected by a 350mA polyfuse if desired. If this part isn’t fitted, then a pair of solder bridge pads are provided within the footprint for the fuse to short out the pads.
For more information on the basic design, please see the original post with the link at the top of the page.
Schematic
Here is an archive of the firmware & the Eagle CAD files for the PCB & schematic design.
As the first USB hub I was using was certainly not stable – it would not enumerate between boots & to get it working again would require waiting around 12 hours before applying power, it has been replaced. This is a cheapie eBay USB hub, of the type shown below.
These hubs are fantastic for hobbyists, as the connections for power & data are broken out on the internal PCB into a very convenient row of pads, perfect for integration into many projects.
Breakout Hub
I now have two internal spare USB ports, for the inbuilt keyboard/mouse receiver & the GPS receiver I plan to integrate into the build.
These hubs are also made in 7-port versions, however I am not sure if these have the same kind of breakout board internally. As they have the same cable layout, I would assume so.
Connector Panel
Here is a closeup of the back of the connectors, showing a couple of additions.
I have added a pair of 470µF capacitors across the power rails, to further smooth out the ripple in the switching power supply, as I was having noise issues on the display.
Also, there is a new reset button added between the main interface connectors, which will be wired into the pair of pads that the Raspberry Pi has to reset the CPU.
This can be used as a power switch in the event the Pi is powered down when not in use & also to reset the unit if it becomes unresponsive.
I have finally got round to designing the balancing circuitry for my ultracapacitor banks, which have a total voltage of 15v when fully charged. The 2600F capacitors have a max working voltage of 2.5v each, so to ensure reliable operation, balancing is required to make sure that each capacitor is charged fully.
The circuit above is a simple shunt regulator, which uses a 2.2v zener diode to regulate the voltage across the capacitor.
A 10W 1Ω resistor is connected to the BALLAST header, while the capacitor is connected across the INPUT. Once the voltage on the capacitor reaches 2.6v, the MOSFET begins to conduct, the 1Ω resistor limiting current to ~2.6A.
Each capacitor in the series string requires one of these connected across it.
PCB
Below is a link to the Eagle project archive for this. Includes schematic, board & gerber files.
This is a late 90’s business timeclock, used for maintaining records of staff working times, by printing the time when used on a sheet of card.
Front Internal
Here is the top cover removed, which is normally locked in place to stop tampering. The unit is programmed with the 3 buttons & the row of DIP switches along the top edge.
Instructions
Closeup of the settings panel, with all the various DIP switch options.
CPU & Display
Cover plate removed from the top, showing the LCD & CPU board, the backup battery normally fits behind this. The CPU is a 4-bit microcontroller from NEC, with built in LCD driver.
PSU & Drivers
Power Supply & prinhead drivers. This board is fitted with several NPN Darlington transistor arrays for driving the dox matrix printhead.
Printhead
Printhead assembly itself. The print ribbon fits over the top of the head & over the pins at the bottom. The drive hammers & solenoids are housed in the circular top of the unit.
Printhead Bottom
Bottom of the print head showing the row of impact pins used to create the printout.
Bottom of the solenoid assembly with the ribbon cable for power. There are 9 solenoids, to operate the 9 pins in the head.
Return Spring
Top layer of the printhead assembly, showing the leaf spring used to hold the hammers in the correct positions.
Hammers
Hammer assembly. The fingers on the ends of the arms push on the pins to strike through the ribbon onto the card.
Solenoids
The ring of solenoids at the centre of the assembly. These are driven with 3A darlington power arrays on the PSU board.
Gearbox Internals
There is only a single drive motor in the entire unit, that both clamps the card for printing & moves the printhead laterally across the card. Through a rack & pinion this also advances the ribbon with each print.
Here are a few details of a valve amplifier I am building, using the valve related parts from a 1960’s reel to reel tape recorder.
This amplifier is based on an a Mullard ECL82 triode/pentode valve, with an EM84 magic eye tube for level indication.
Beginnings Of The Amplifier
Here the first components are being soldered to the tags on the valve holder, there are so few components that a PCB is not required, everything can be rats-nested onto the valve holders.
Progress
Progressing with the amplifier section componentry, all resistors are either 1/2W or 2W.
Valve Sockets Fitted
Here the valve holders have been fitted, along with the output transformer, DC smoothing capacitor & the filament wiring, into the top of the plastic housing. At this point all the components that complete the amplifier section are soldered to the bottom of the right hand valve holder.
Wiring
Starting the wiring between the valves & the power supply components. The volume control pot is fitted between the valve holders.
Valves Test Fit
The valves here are test fitted into their sockets, the aluminium can at the back is a triple 32uF 250v electrolytic capacitor for smoothing the B+ rail.
Amplifier Section First Test
First test of the amplifier, with the speaker from the 1960’s tape recorder from which the valves came from. the 200v DC B+ supply & the 6.3v AC filament supply is derived from the mains transformer in the background.
Magic Eye Tube Added
Here the magic eye tube has been fitted & is getting it’s initial tuning to the amplifier section. This requires selecting combinations of anode & grid resistors to set the gap between the bars while at no signal & picking a coupling RC network to give the desired response curve.
Final Test
Here both valves are fitted & the unit is sitting on it’s case for final audio testing. the cathodes of the ECL82 can be clearly seen glowing dull red here.
In the final section, I will build a SMPS power supply into the unit to allow it to be powered from a single 12v DC power supply.
Here is an old chemical dosing system for industrial washing machines. These units are 4-pump models, with dual pumpheads. The motors are reversed to operate alternate pumps in the same head.
Label
From 2006, this is a fairly old unit, and made in the UK.
CPU Board
Main controller PCB, with interface to the power electronics via the ribbon cable, an external serial port for programming to it’s left. Powered by an ST microcontroller. The LCD is below this board.
PCU & Driver PCBs
Main power supply, sense input & motor driver boards. The PSU outputs +5v, +12v & +24v. The inputs on the lower left connect to the washing machine & trigger the pumps via the programming on the CPU. The motors are driven by L6202 H-Bridge drivers from ST.
Motor Assembly
Motor & gearbox assembly on the back of the pumphead. These are 24v DC units with 80RPM gearboxes.
UPDATE:
As it seems to be difficult to find, here is the user manual for this unit:
[download id=”5557″]
This is the control unit for a Routemaster system, that downloads traffic information for the area local to the vehicle.
Unit Overview
Here is an overview of the unit, in it’s aluminium box.
Here is the unit with the top cover removed, showing the pair of PCBs. The bottom PCB is the main control PCB, the top one holds an IC similar to a SIM card & part of the radio.
Cover Removed
Main PCB Top
Here is the main PCB removed from the casing, contains the program ROM & microcontroller. for the system
Daughtercard view. This holds another programmed CPLD, the custom SIM-like IC & the RTC battery, along with some power conversion circuitry.
Daughterboard Top
Radio Receiver
This is the radio receiver, looks to be AM, the large loop antenna can be seen at the bottom of the box.
After seeing these on eBay for £8.99 I thought it might be a good deal – interfacing with the RasPi’s GPIO & it has built in power supplies.
As a kit, it was very easy to assemble, the PCB quality is high, and is a fairly good design. It worked first time, the regulators hold the rails at the right voltages.
However there are some issues with this board that bug me.
The documentation for the kit is *AWFUL*. No mention of the regulators on the parts list & which goes where – I had to carefully examine the schematics to find out those details.
The 4x 1N1007 diodes required weren’t even included in the kit! Luckily I had some 1N4148 high speed diodes lying around & even though they’re rated for 200mA continuous rather than the specified part’s 1A rating, the lack of heatsinking on the regulators wouldn’t allow use anywhere near 1A, so this isn’t much of a problem.
Component numbering on the silkscreen isn’t consistent – it jumps from R3 straight to R6! These issues could be slightly confusing for the novice builder, and considering the demographic of the RasPi, could be seen as big issues.
On the far left of the board are the 5v & 3.3v regulators, well placed on the edge of the board in case a heatsink may be required in the future. However the LM317 adjustable regulator is stuck right in the middle of the PCB – no chance of being able to fit a heatsink, & the device itself seems incredibly cheap – the heatsink tab on the back of the TO-220 is the thinnest I have ever seen. Not the usual 2-3mm thick copper of the 5v & 3.3v parts – but barely more than a mm thick, so it’s not going to be able to cope with much power dissipation without overheating quickly.
As the adjustable rail can go between ~2.5v – 10v, at the low end of the range the power dissipation is going to shoot through the roof.
The GPIO connector – this could have been done the other way, at the moment the ribbon cable has to be twisted to get both the Pi & the GPIO board the same way up. Just a slight fail there. See the image below
Plugged In
The power rails are not isolated out of the box – there is no connection between the 5v & 3.3v rails & the Pi’s GPIO, but the GND connections are linked together on the board.
Getting the ribbon cable through the hole in the ModMyPi case was a bit of a faff – the connector is too big! I had to squeeze the connector through at a 45° angle. The case is also remarkably tight around the connector once it’s fitted to the board – clearly the designers of the case didn’t test the an IDC connector in the case before making them!
Everything does fit though, after a little modification.
All Cased Up
Here is the unit all built up with the case. The top cover just about fits with the IDC connector on the GPIO header.
More to come once I get some time to do some interfacing!
Here’s the teardown of the projector itself! On the right is the info label from the projector, which covers the flex ribbon to the VGA/composite input board below.
This unit is held together with Allen screws, but is easy to get apart.
PicoP Display Engine
Here’s the insides of the projector, with just the top cover removed. The main board can be seen under the shielding can, the Micro HDMI connector is on the left & the MicroUSB connection is on the right. The USB connection is solely for charging the battery & provides no data interface to the unit.
On top of the main board is the shield can covering the PicoP Display Engine driver board, this shield was soldered on so no peek inside unfortunately!
Laser Module
The laser module itself is in the front of the unit, the laser assemblies are closest to the camera, on the left is the Direct Doubled Green module, in the centre is the blue diode, and the red diode on the right. Inside the module itself is an arrangement of mirrors & beamsplitters, used to combine the RGB beams from the lasers into a single beam to create any colour in the spectrum.
Module Innards
Here is the module innards revealed, the laser mounts are at the top of the screen, the green module is still mounted on the base casting.
The three dichroic mirrors in the frame do the beam combining, which is then bounced onto the mirror on the far left of the frame, down below the MEMs. From there a final mirror directs the light onto the MEMs scanning mirror before it leaves through the output window.
A trio of photodiodes caters for beam brightness control & colour control, these are located behind the last dichroic turning mirror in the centre of the picture.
Green Module Cavity
This is inside the green laser module, showing the complexity of the device. This laser module is about the size of a UK 5p coin!
Green Module Labeled
And here on the left is the module components labelled.
Main PCB Top
Here is the main PCB, with the unit’s main ARM CPU on the right, manufactured by ST.
User buttons are along the sides.
Main PCB Bottom
Other side of the main board, with ICs that handle video input from the HDMI connector, battery charging via the USB port & various other management.
Here is a 2Gbit Fibre Channel transceiver from Cisco Systems in SFP module format.
Shield Removed
Here the shield has been removed from the bottom of the module (it just clips off). The bottom of the PCB can be seen, with the copper interface on the left & the rubber boots over the photodiode & 850 nm laser on the right.
PCB Bottom
Here the PCB has been completely removed from the frame, the fibre ends slide into the rubber tubes on the right.
PCB Top
Top of the PCB, showing the chipset. There are a pair of adjustment pots under some glue, next to the chipset, presumably for adjusting laser power & receive sensitivity. The laser diode & photodiode are inside the soldered cans on the right hand side of the board, with the optics required to couple the 850nm near-IR light into the fibre.
This is the teardown of a Zebra P330i plastic card printer, used for creating ID cards, membership cards, employee cards, etc. I got this as a faulty unit, which I will detail later on.
This printer supports printing on plastic cards from 1-30mils thick, using dye sublimation & thermal transfer type printing methods. Interfaces supplied are USB & Ethernet. The unit also has the capability to be fitted with a mag stripe encoder & a smart card encoder, for extra cost.
Print Engine
On the left here is the print engine open, the blue cartridge on the right is a cleaning unit, using an adhesive roller to remove any dirt from the incoming card stock.
This is extremely important on a dye sublimation based printing engine as any dirt on the cards will cause printing problems.
Cards In Feeder
Here on the right is the card feeder unit, stocked with cards. This can take up to 100 cards from the factory.
The blue lever on the left is used to set the card thickness being used, to prevent misfeeds. There is a rubber gate in the intake port of the printer which is moved by this lever to stop any more than a single card from being fed into the print engine at any one time.
Card Feeder Belt
Here is the empty card feeder, showing the rubber conveyor belt. This unit was in fact the problem with the printer, the drive belt from the DC motor under this unit was stripped, preventing the cards from feeding into the printer.
Print Head
Here is a closeup of the print head assembly. The brown/black stripe along the edge is the row of thin-film heating elements. This is a 300DPI head.
Print Station
This is under the print head, the black roller on the left is the platen roller, which supports the card during printing. The spool in the center of the picture is the supply spool for the dye ribbon.
In the front of the black bar in the bottom center, is a two-colour sensor, used to locate the ribbon at the start of the Yellow panel to begin printing.
LCD PCB
Inside the top cover is the indicator LCD, the back of which is pictured right.
This is a 16×1 character LCD from Hantronix. This unit has a parallel interface.
LCD
Front of the LCD, this is white characters on a blue background.
Roller Drive Belts
Here is the cover removed from the printer, showing the drive belts powering the drive rollers. There is an identical arrangement on the other side of the print engine running the other rollers at the input side of the engine.
Mains Filter
Here the back panel has been removed from the entire print engine, complete with the mains input wiring & RFI filtering.
This unit has excellent build quality, just what is to be expected from a £1,200+ piece of industrial equipment.
Main Frame With Motors
The bottom of the print engine, with all the main wiring & PCB removed, showing the main drive motors. The left hand geared motor operates the head lift, the centre motor is a stepper, which operates the main transmission for the cards. The right motor drives the ribbon take up spindle through an O-Ring belt.
Feeder Drive Motor
Card feeder drive motor, this connects to the belt assembly through a timing belt identical to the roller drive system.
All these DC geared motors are 18v DC, of varying torque ratings.
Power Supply
Here is the main power supply, a universal input switch-mode unit, outputting 24v DC at 3.3A.
PSU Label
PSU info. This is obviously an off the shelf unit, manufactured by Hitek. Model number FUEA240.
Print Engine Rear
The PSU has been removed from the back of the print engine, here is shown the remaining mechanical systems of the printer.
Print Engine Components
A further closeup of the print engine mechanical bay, the main stepper motor is bottom centre, driving the brass flywheel through another timing belt drive. The O-Ring drive on the right is for the ribbon take up reel, with the final motor driving the plastic cam on the left to raise/lower the print head assembly.
The brass disc at the top is connected through a friction clutch to the ribbon supply reel, which provides tension to keep it taut. The slots in the disc are to sense the speed of the ribbon during printing, which allows the printer to tell if there is no ribbon present or if it has broken.
RFID PCB
Here is a further closeup, showing the RFID PCB behind the main transmission. This allows the printer to identify the ribbon fitted as a colour or monochrome.
The antenna is under the brass interrupter disc on the left.
I/O Daughterboard
The I/O daughterboard connects to the main CPU board & interfaces all the motors & sensors in the printer.
Main PCB
Here is the main CPU board, which contains all the logic & processing power in the printer.
CPU
Main CPU. This is a Freescale Semiconductor part, model number MCF5206FT33A, a ColdFire based 32-bit CPU. Also the system ROM & RAM can be seen on the right hand side of this picture.
Ethernet Interface
Bottom of the Ethernet interface card, this clearly has it’s own RAM, ROM & FPGA. This is due to this component being a full Parallel interface print server.
Ethernet Interface Top
Top of the PCB, showing the main processor of the print server. This has a ferrite sheet glued to the top, for interference protection.
This is just a few notes on the repair of an eCig battery (1Ah Tornado).
These batteries seem to have a flaw in which they will randomly stop working, while still displaying all the normal activity of the battery.
Here is what I have found.
Control PCB
Here the battery has been partially disassembled, with the control circuitry exposed here at the end of the unit. All the wiring here is fine & the electronics themselves are also OK, due to the LEDs still operating as normal when the button is pushed. The 1000mAh Li-Poly cell is to the right.
Ground Wire
Here the end cap has been removed from the opposite end of the battery & the problem is found: the short wire here is the GND return for the atomiser, normally connected to the negative terminal of the battery in the tube, however here it has broken off.
This is most likely due to either the cell moving inside the tube during normal operation, weakening the solder joint, or simply a bad solder job from the factory. (This lead-free ROHS bullshit is to blame).
Repaired
Here the wire has been successfully soldered back on to the battery tab. I have also added a small dab of hot glue to hold the battery in place on the inside of the tube, & replaced the solder on the joints with real 60/40 leaded solder. £15 saved.
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 PCB for a programmable amount of time.
Main PCB
Closeup of the main PCB, 12v DC input at top right. Left IC is an LM358 dual Op-Amp, the IC on the right is a PIC12F629 with Velleman’s custom firmware.
Logic power is supplied to the ICs & the oscillator from the LM7805 regulator at the top of the PCB. The relay is a standard 15A SPDT 12v coil relay, with the switch contacts broken out onto the screw terminals on the left.
Schematic Diagram
As it is not provided with the kit, unlike other Velleman kits, here is the schematic for this.
This unit was bought from eBay to experiment with Magnetic Stripe cards, for little money. This unit is capable of reading & writing all 3 tracks, & both Hi-Co & Lo-Co card types.
Interfaced to a PC through USB, this has a built in PL2303 USB-Serial IC & requires 3A at 9v DC to operate.
The 3 Indicator LEDs on the top of the unit can be toggled by the included software for Power/OK/Fault condition signalling.
Unit Bottom
Bottom of the unit with the model labels.
Model Label
Closeup of the model label & serial number.
PCB Bottom
Here the bottom cover has been removed, showing the main PCB. The pair of large ICs bottom center interface with the magnetic heads. The IC above them has had the markings sanded off.
USB-Serial Interface
Closeup of the Prolific PL-2303 USB-Serial converter IC.
PCB Top
Here the connections to the R/W heads are visible, current limiting resistors at the left for the write head, a pair of signal relays, a pair of optoisolators & a LM7805 linear voltage regulator.
LEDs
Here is the trio of indicator LEDs on a small sub-board.
Frame Bottom
The PCB has been removed from the main frame here, the only component visible is the rotary encoder.
Rotary Encoder
The rotary encoder has a rubber wheel fitted, which reads the speed of the card as it is being swiped for writing. This allows the control logic to write the data to the stripe at the correct rate for the speed of the card. This allows the unit to write cards from 5-50 inches per second speed.
The Write head is directly behind the rubber pressure roller.
Read/Write Heads
Here you can see the R/W head assembly. The write head is on the right, read on the left. When a card is written to, it immediately gets read by the second head for verification.
Stripboard Magic is a Windows application for designing PCB layouts on stripboard (aka prototyping board, aka Veroboard). It was released by a British company called Ambyr which ceased trading a long time ago.
The interface is a quite primitive and a little strange but the program is functional even on Windows XP. It also works great under wine in Linux, at least with version 0.9.38 and above as this is all I have checked. It should probably work on older versions too. I haven’t tried it on Vista though.
It can be a handy program when called upon and I have successfully used it a few times when throwing together random small circuits. Due to the interface I would imagine it to be a bit clumsy for very large circuits. The biggest gripe I have with it is the inability to change the orientation of components on the board, so some circuits tend to be slightly larger than they need to be.
I downloaded a copy of Stripboard Magic 1.0 back in the 90’s and recently just found it lying about on my computer. As I would consider it to well and truly be abandonware and as it seems to be a little sought after by some hobbyists I have provided a link to download it below.
[download id=”5624″]
Here are some screenshots showing the schematic view (top) and board layout view (bottom):
Stripboard Designer
Another hard to find app these days is Stripboard Designer, mirrored here for people who wish to use it.
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.
Screen
Here is the front face of the CRT, diameter is 0.5″.
Power Board
Closeup view of the PCB, there are several adjustments & a pair of connectors. Socket in the upper left corner is the power/video input. Pinout is as follows:
Brown – GND
Red – Video Input
Orange – +12v DC
Yellow – Record LED
The potentiometers on the PCB from left:
H. ADJ
V. ADJ
BRIGHT
FOCUS
PCB Part Number reads: EM6-PCB
This unit utilises the BA7125L deflection IC.
Solderside
Reverse side of the PCB, very few SMT components on this board.
Tube Assembly
Here is an overall view of the CRT assembly with scan coils. Tube model is NEC C1M52P45.
Electron Gun
Closeup view of the CRT neck, showing the electron gun assembly.
CCTV Camera
The old CCTV camera used to feed a composite signal to the CRT board. Sanyo VCC-ZM300P.
CCTV Camera Connections
Connections at the back of the camera. Red & Black pair of wires lead to 12v power supply, Green & Black pair lead to the CRT board’s power pins. Seperate green wire is pushed into the BNC video connector for the video feed. video ground is provided by the PSU’s ground connection.
Connections
Finally the connections at the CRT drive board, left to right, +12v, Video, GND.
This is a cheap Sigma branded keychain photoframe. User buttons for power & selecting photos are on the left.
There are two white LEDs on the bottom edge that function as a torch as well.
Display
Front of the unit removed, showing the LCD module. The USB jack is bottom left, next to the pair of white LEDs & above that is the 32kHz watch crystal that the CPU uses for timekeeping.
Back Removed
Here the back has been removed showing the 3.7v Li-Ion cell used to provide power.
Display Folded Back
Here the display has been removed from the PCB exposing the chipset.
Chipset
Here the CPU blob-top chip & a flash memory IC are visible. The CPU is a Sitronix ST2205U.
This is a small 120W power inverter, intended for small loads such as lights, fans, small TVs & laptop computers.
End Cover
End cover of the unit, 12v DC input cord at the top, power switch & indicator LEDs at the bottom.
Mains Output
Opposite end of the unit, with the standard 240v AC 50Hz Mains output socket.
Cover Removed
Cover removed from the top of the unit. Main power transformer is visible in the centre here, MOSFET bank is under the steel clamp on the left, the aluminium case forms the heatsink.
PWM Controllers
On the right is a KA3525 switchmode PWM controller & on the left is a LM324N quad Op-Amp IC. The buzzer on the far left is for the low battery warning.
PCB Removed
PCB removed from the casing, with the MOSFET bank on the right hand side. Two potentiometers in the centre of the board tweak the frequency of the switcher & the output voltage.
Here is a Inductive charger designed for the Nintendo DSi. Cheap Chinese build, but it does work!
Overview
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 indicates charging status.
Induction coil is on the left, with the controller & oscillator PCB at the top.
PCB Closeup
Closeup of the PCB, ICs have had their markings ground off.
Coil
Induction coil. This couples power into a coil built into a special battery, supplied with the base, to charge it when the DSi is placed on the dock.
Label
Information Label on the base.
Power Input
Standard DSi charger port, connects to the charger you get with the DSi. Power switch is on the right.
Here is a label maker, bought on offer at Maplin Electronics. Full Qwerty keyboard with 1 line dot matrix LCD display visible here. Power is 4 AAA cells or a 6v DC Adaptor.
Rear
Rear cover removed. Battery compartment is on the left hand side, space for the tape cartridge on the right. Ribbon cable leading to the thermal print head is on the far right, with rubber tape drive roller.
PCB
PCB under the top cover with the main CPU, a MN101C77CBM from Panasonic. This CPU features 48K Mask ROM & 3K of RAM. Max clock frequency is 20MHz. 32kHz clock crystal visible underneath a Rohm BA6220 Electronic speed controller IC.
This is used to drive the printer motor at a constant accurate speed, to feed the tape past the thermal head. Miniature potentiometer adjusts speed.
Ribbon cable at the bottom of the board connects to the print head, various wiring at the left connects to the battery & DC Jack.
Printer Drive
Printer drive mechanism. Small DC motor drives the pinch roller though a gear train. DC Jack & reverse polarity protection diode is on the right.
This unit uses a centre negative DC jack, which is unusual.
Cartridge
Thermal tape cartridge, black text on white background.
Here is an old type KVM switch, PS/2 & VGA interface.
Label
Details Label
Top Removed
Top removed from the main body, the cables coming in from the bottom connect to the VGA, keyboard & mouse ports on the slave computers, the connectors at the top connect to the single monitor, keyboard & mouse.
PCB
PCB removed from the body. This is driven by a PIC16C57C-04 microcontroller.
The pair of LEDs indicate which computer is using the peripherals at any one time.
Here is a cheap USB 8-in-1 card reader. Power & Access LEDs are on top left.
PCB Top
Top of the PCB. The OTi IC is the interface IC to the USB port, part number is OTI002126. Card sockets on the top here are CF/Microdrive & Memory Stick.
Top removed from the mouse, the ball fits in the gap in the centre. The slotted discs are visible which contact the ball & move relative to the surface the mouse is on.
PCB
PCB removed from the shell. Pairs of IR LEDs & Phototransistors make rotary encoders with the slotted discs. The microswitches read the mouse buttons & wheel.
IC in the centre interfaces with the PC over a PS/2 connection.
A 5 megapixel digital camera from Vivitar. Visible here is the lens, viewfinder & flash.
Back
Rear of the unit showing the LCD & user control buttons.
Cover Removed
Front frame removed showing some of the internals. Shutter assembly & lens in centre, battery compartment at left.
Rear Cover Removed
Rear frame removede, showing the LCD module & tactile switches.
LCD
LCD module removed from the PCB
Flash PCB
Flash PCB removed. Transformer is fed with the 4.5v from the 3 AA cells & steps it up to ~300v DC for the flash capacitor. A pulse transformer energizes an electrode next to the Xenon flash tube with ~5kV to ionize the gas.
Main PCB
Main PCB removed. Internal flash ROM & RAM IC visible above the SD card socket. USB connector is at the top right, next to the piezo buzzer.
CPU
Main processor on reverse side of the PCB.
Image Sensor
Closeup of the CMOS image sensor with the lens assembly removed.
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