Following on from my review, here are some internal views & detail on the components used in this radio. Below is an overview of the main PCB with the top plate removed from the radio.
Cover RemovedRF Final Amplifier Stage
Most visible are these MOSFETs, which are Mitsubishi RD70HVF1 VHF/UHF power devices. Rated for a maximum of 75W output power at 12.5v (absolute maximum of 150W, these are used well within their power ratings. They are joined to the PCB with heavy soldering, with bypass caps tacked right on to the leads.
RF Pre Drivers
Here is the RF pre-driver stage, with intermediate transistors hidden under the small brass heatspreader.
Power Section
In the top left corner of the radio, near the power input leads, is the power supply & audio amplifier section. Clearly visible are the pair of LA4425A 5W audio power amplifier ICs, these drive the speakers on the top of the radio. Either side of these parts are a 7809 & a 7805 – both linear regulators providing +9v & +5v logic supplies respectively. The large TO220 package device is a KIA378R08PI 3A LDO regulator with ON/OFF control, this one outputs +8v. Just visible in the top right corner are the sockets for the speaker connections.
DTMF Circuits
Here are the two ICs for dealing with DTMF tones, they are HM9170 receivers.
Glue Logic
In the corner next to the interface jack, there are some CD4066B Quad Bilateral switches. These make sense since the interface jack has more than a single purpose, these will switch signals depending on what is connected.
RF Section
Here are visible the RF cans for the oscillators, the crystals visible next to the can at the top. The shields are soldered on, so no opening these unfortunately.
Also visible in this image is a CMX138A Audio Scrambler & Sub-Audio Signalling processor. This IC deals with the Voice Inversion Scrambling feature of the radio, & processes the incoming audio before being sent to the modulator.
Output Filter Network
Shown here is the RF output filter network, this radio uses relays for switching instead of PIN diodes, I imagine for cost reasons. The relay closest to the RF output socket has had a slight accident 🙂 This is slated to be replaced soon.
RF Output Jack
Finally, the RF output jack.
Audio Speakers
Here the speakers are shown, attached to the bottom of the top plate. They are both rated 8Ω 1W.
After running on handies for all of my Ameteur Radio life, I figured it was time for a new radio, this time a base station/mobile rig, & after some looking around I decided on the Wouxun KG-UV950P.
Shown below is the radio as delivered:
Wouxun Boxed
This radio has the capability to transmit quad-band, on 6m, 10m, 2m & 70cm. It also has the capability to receive on no fewer than eight bands. Also included in the feature set is airband receive, & broadcast FM receive.
TX power is up to 50W on 2m, 40W on 70cm, & 10W on 6m/10m.
Opened
For once with a Chinese piece of electronic equipment, the manual is very well printed, and in very good English.
Radio Operating
Here is the radio in operation, connected to my 65A 12v power supply. I have the radio set here monitoring a couple of the local 70cm repeaters.
The display is nice & large – easy to see at a glance which station you’re tuned to. The backlight is also software settable to different colours.
Status indicators on the top edge of the display can be a bit difficult to see unless the panel is directly facing the user though, not to mention that they are rather small.
This radio is true dual-watch, in that both VFOs can be receiving at the same time, this is effected by a pair of speakers on the top panel:
Speakers
The left VFO speaker is smaller than the right, so the sound levels differ slightly, but overall sound quality is excellent. There is also provision on the back of the unit to connect external speakers.
The dual volume controls on the right hand bottom corner of the control panel are fairly decent, if a little twitchy at times. There is also a fair amount of distortion on the audio at the higher volume levels.
The controls themselves are potentiometers, but the controller appears to read the setpoint with an ADC – this means that if the control is set to just the right point, the selected level will jump around on the display & never settle down.
The radio itself is built from a solid aluminium casting, mostly for heatsinking of the main RF output stage MOSFETs. This gives the radio a very rugged construction.
A small fan is provided on the rear for cooling when required. This can be set in software to either be constantly running, (it’s pretty much silent, so this is advantageous), or only run when in TX mode. The fan will also automatically come on when a high internal temperature is detected.
Hand Mic
Here is the microphone. Like the main unit of the radio this is also very solidly built, fits nicely in the hand & the PTT has a nice easy action, which helps to prevent straining hands while keeping the TX keyed.
Conveniently, all of the controls required to operate the radio are duplicated on this mic, along with a control lock switch, & backlighting for the buttons.
Another Speaker
Another output speaker is placed in the back of the mic. This one can be activated through the menu system, to either use the main body speakers, the mic mounted one, or both.
A mounting hook for the mic is provided to attach to any convenient surface.
Radio Back
Here’s the back of the radio, with some of the big heatsink fins, the fan in the centre. To the left is the PL259 RF output, this looks to be a high quality Teflon insulated one. On the right are the power input leads & the external speaker outputs.
External Speaker Sockets
The external speaker connections are via 3.5mm jacks. I haven’t yet tested this feature.
Remote Mounting Plate
The control panel of this radio is detachable from the main body, and a pair of adaptors are provided. This either allows the radio display to be angled upwards toward the user, set parallel, or even mounted remotely. A control extension cable is provided to allow the main body to be mounted a fair distance away.
External Interface Connectors
On the left of the radio is the PC control & programming port, & the mic connector. Wouxun *really* like RJ-45 connectors, they’ve used them for everything on this radio.
Also visible here is the tilted faceplate adaptor.
The supplied software to program the radio, while functional, is absolutely horrific. Hopefully someone will add support for this radio into CHIRP. Anything would be an improvement in this area.
Everything considered, I like this radio. It’s very solidly built, easy to use, and sounds brilliant.
TX audio is great, (or so my other contacts tell me).
Unsurprisingly, the unit gets warm while transmitting, however on high power, it does get uncomfortably warm, and the built in fan does little in the way of helping when a long QSO is in progress. I may remedy this at some stage with a more powerful fan. A little more airflow would do wonders.
If the programming software was built as well as the radio, I’d have zero serious complaints.
At full power, the radio pulls ~10A from the power supply, at 12.9v DC.
As for the antenna I’m currently using, it’s a Diamond X30, mounted on a modified PA speaker stand, at ~30 feet above ground. The feeder is high quality RG-213.
TX Antenna
When I manage to get the set disconnected, a partial teardown will be posted, with some intimate details about the internals. Stay tuned!
Here’s another active balancing circuit for large ultracapacitor banks, this one is designed for a series string of 6, at 2.5v per capacitor.
Based on the design here, I have transcribed the circuit into Eagle & designed a PCB layout.
Ultracap Balancer Circuit – Click to Embiggen
As can be seen from the circuit diagram above, this is just 6 copies of the circuit from the above link, with screw terminals to attach to the capacitor string.
Ultracap Balancer PCB
And here’s the PCB. the MOSFETs & OpAmps are very small SMT parts, so require a steady hand in soldering. This board can easily be etched by hand as there’s only 3 links on the top side. No need for a double sided PCB.
As always, the Eagle project files & my Eagle library collection are available below:
I have recently begun to create an archive of all my personal data, and since LTO2 tape drives offer significant capacity (200GB/400GB) per tape, longevity is very high (up to 30 years in archive), & relatively low cost, this is the technology I’ve chosen to use for my long term archiving needs.
Unfortunately, this drive was DOA, due to being dropped in shipping. This drop broke the SCSI LVD connector on the back of the unit, & bent the frame, as can be seen below.
Broken SCSI
As this drive is unusable, it made for a good teardown candidate.
Cover Removed
Here the top cover of the drive has been removed, showing the top of the main logic PCB. The large silver IC in the top corner is the main CPU for the drive. It’s a custom part, but it does have an ARM core.
The two Hitachi ICs are the R/W head interface chipset, while the smaller LSI IC is the SCSI controller.
The tape transport & loading mech can be seen in the lower half of the picture.
Main Logic
Close up of the main logic.
Tape Spool
Here the main logic PCB has been removed, showing the tape take up spool. The data cartridges have only one spool to make the size smaller. When the tape is loaded, the drive grabs onto the leader pin at the end of the tape & feeds it onto this spool.
The head assembly is just above the spool.
Bottom Plate Removed
Bottom of the drive with the cover plate removed. Here the spindle drive motors are visible, both brushless 3-Phase units. Both of these motors are driven by a single controller IC on the other side of the lower logic PCB.
Head Drive Motor
The head is moved up & down the face of the tape by this stepper motor for coarse control, while fine control is provided by a voice coil assembly buried inside the head mount.
Tape Head Assembly
The face of the tape R/W head. This unit contains 2 sets of 8 heads, one of which writes to the tape, the other then reads the written data back right after to verify integrity.
Cartridge Load Motor
The tape cartridge loading motor. I originally thought that this was a standard brushed motor, but it has a ribbon cable emerging, this must be some sort of brushless arrangement.
A replacement drive is on the way, I shall be documenting some more of my archiving efforts & system setup once that unit arrives.
Here is a ZyXel WAP3205 WiFi Access Point that has suffered a reverse polarity event, due to an incorrect power supply being used with the unit.
ZyXEL WAP3205
While most electronic gadgets are protected against reverse polarity with a blocking diode, this unit certainly wasn’t. Applying +12v DC the wrong way round resulted in this:
Blown Switchmode IC (Fuzzy Focus)
That is the remains of the 3.3v regulator IC, blown to smithereens & it even attempted an arson attack. Luckily this was the only damaged component, & I was able to repair the unit by replacing the switching IC with a standalone regulator. (Replacing the IC would have been preferable, if there was anything left of it to obtain a part number from).
I scraped away the pins of the IC to clear the short on the input supply, removed the switching inductor, & tacked on an adjustable regulator module set to 3.3v. Luckily the voltage of the supply is handily marked on the PCB next to the circuit.
Replacement PSU
Replacement SMPS in place on top of the PCB. The output of the supply is connected to one of the pads of L4 (on my unit just an 0 ohm link), the +12v input is connected to the + rail side of C8 & C7 & the final ground connection is hooked in to the back of the barrel jack.
After this replacement, the unit booted straight up as if nothing had happened. All the logic is undamaged!
I recently came across a design for an Arduino controlled AD9850 DDS module, created by AD7C, so I figured I would release my Eagle CAD design for the PCB here.
It is a mainly single-sided layout, only a few links on the top side are needed so this is easy to etch with the toner transfer method.
My version uses an Arduino Pro Mini, as the modular format is much easier to work with than a bare ATMega 328.
RF output is via a SMA connector & has a built in amplifier to compensate for the low level generated by the DDS Module.
DDS VFO
Version 2 Update: Added reverse polarity protection, added power indicator LED, beefed up tracks around the DC Jack.
[download id=”5571″]
As there was no other online example of someone converting a glow/nitro car engine onto CDI ignition, I thought I would document the highlights here.
The engine is currently still running on glow fuel, but when the required fuel lines arrive I will be attempting the switch over to 2-Stroke petrol mix. This should definitely save on fuel costs.
The engine in this case is a HPI NitroStar F4.6 nitro engine, from a HPI Savage X monster truck.
F4.6 Engine
Above is the converted engine with it’s timing sensor. As The installation of this was pretty much standard, a complete strip down of the engine was required to allow the drilling & tapping of the two M3x0.5 holes to mount the sensor bracket to. The front crankshaft bearing has to be drifted out of the crankcase for this to be possible.
Ignition Hall Sensor
Detail of the ignition hall sensor. The bracket has to be modified to allow the sensor to face the magnet in the flywheel. Unlike on an Aero engine, where the magnet would be on the outside edge of the prop driver hub, in this case the hole was drilled in the face of the flywheel near the edge & the magnet pressed in. The Hall sensor is glued to the modified bracket with the leads bent to position the smaller face towards the back of the flywheel.
The clearance from the magnet to sensor is approx. 4mm.
Flywheel Magnet
Detail of the magnet pressed into the flywheel. A 3.9mm hole was drilled from the back face, approx 2mm from the edge, & the magnet pressed into place with gentle taps from a mallet & drift, as I had no vice to hand.
Initial timing was a little fiddly due to the flywheel only being held on with a nut & tapered sleeve, so a timing mark can be made inside the rear of the crankcase, across the crank throw & case to mark the 28 degree BTDC point, the flywheel is then adjusted to make the ignition fire at this point, before carefully tightening the flywheel retaining nut to ensure no relative movement occurs.
The slots in the sensor bracket allow several degrees of movement to fine adjust the timing point once this rough location has been achieved.
1/4″-32 Spark Plug
Definitely the tiniest spark plug I’ve ever seen, about an inch long. Some trouble may be encountered with this on some engines – the electrodes stick out about 2mm further into the combustion chamber than a standard glow plug does. This causes the ground electrode to hit the top of the piston crown. (This happens on the HPI NitroStar 3.5 engine). The addition of another copper washer under the plug before tightening should cure this problem.
RcExl CDI Ignition Module
Ignition module. Due to the depth of the plug in the heatsink head on these engines, I will have to modify the plug cap to straighten it out, as it will not fit in this configuration.
However, ignition modules are available from HobbyKing with straight plug caps, this makes modification unnecessary
The ignition & components used on this system were obtained from JustEngines.
After 13 months of very heavy use at various events, festivals & boat trips, the Li-Po battery pack at the heart of my portable power supply has died.
What initially started as one cell inflating spread to the other cells in the pack over a period of about 3 months, so I have completely replaced the pack with a larger unit.
New Pack
The old pack was an 8.8Ah unit at 12.6v. By using smaller burst capacity cells, I have managed to squeeze in a total of 13.2Ah, still leaving space to spare for an extra 3 cell string along the top.
Cell Interconnects
Here is the end of the battery pack, with all the cell interconnects. There are 3 2.2Ah cells in series to give the 12.6v terminal voltage, with 6 of those strings in parallel to give the total Ah rating.
A new charging circuit will be implemented to better handle the volatile chemistry of Li-Po cells, hopefully this will result in the pack lasting longer than a year!
The new higher capacity will hopefully help with power requirements at future events, still being charged during the day by a 24W solar panel, but at night will have to cope with charging two smartphones, two eCigs & running a few watts of LED lighting.
The trial-by-fire will be this year’s Download Festival in June, when I will be operating off-grid for 6 days.
The quickest project from inception to working PCB yet:
From inception to a working PCB took only 4 hours!
LM386 Amplifier
This is a miniature stereo audio amplifier, 0.5W per channel, that can be run from any voltage between 4-12v DC.
As usual, all the Eagle project files are available for download below & kits/bare PCBs will be available for sale for those that cannot etch boards.
In Operation
Here is the circuit driving a pair of 3W 8Ω speakers from a line level audio source. The gain of this circuit is set at 50 with the components specified.
Schematic
As can be seen from the schematic, this is a pair of single LM386 ICs for each channel.
Here is a home laser hair removal unit, a Rio LAHS4. Shown above is the system overview, with the laser wand & the user controls.
Main PCB Top
Main base unit popped open reveals the main PCB, with the central processor, a PIC16F628A.
Main PCB Bottom
Other side of the PCB is mainly populated with power supply & filtering for the logic sections.
Wand PCB
Cracking open the laser wand reveals a stacked pair of PCBs, a main laser controller & the capacitive sensor PCB. This capacitive sensor connects to a pair of pins on the laser head & prevents operation if the unit is not held firmly against the skin.
Diode Module
Front of the laser diode module with the movable lens, on a pair of voice coil actuators. Very similar to the lens positioner used in any CD/DVD player pickup assembly.
The diode in this unit is an 808nm chip, with power in the 300-600mW range most likely.
Diode Module Rear
Rear of the diode module, with the connections to the diode itself & the voice coil positioner for the lens.
Wand PCB Top
Other side of the wand PCB, showing the capacitive sensor board on top of the main controller board. There is another CPU on the board here, which most likely communicates with the main processor in the base through a serial connection.
This is a passenger side airbag from a BMW vehicle. Here is the top of the device, with all the warning labels & information.
Folded Bag
Here the outer plastic wrap has been removed from the unit, showing the folded nylon fabric bag.
Frame
The base frame with the gas generator mounted.
Gas Generator
Gas generator with warning label. This is a two part generator, with a pair of independent cores inside.
Generator Core
One of the generator cores removed from the heavy steel shell of the gas generator. The layers of wire mesh on the outside act as a flame trap, releasing only the gas generated from the burning propellant inside.
Propellant
End cap removed from the core, showing the pellets of propellant & the many layers of mesh & fibreglass filter material. The explosive initiator is in the bottom of this unit. A spring under the end cap firmly holds the pellets against the initiator.
Initiator
Finally, here is the explosive initiator that is located in the bottom of the core under the propellant pellets. This consists of a primary explosive & an electric match, which can be seen below as the device is disassembled.
Here is the latest build & addition to the boat, in preparation for delivery of an 8kVa hydraulically driven generator unit – an automatic transfer switch.
Above can be seen the completed contactor unit, mounted in the engine bay.
This unit takes feeders from both the shore power socket & the generator unit & switches them independently through to the domestic 240v AC systems on board.
Contactor switching is done by a Datakom DKG-171 automatic generator controller.
Switching Unit
Here are the contactors & isolators, before fitting to the wallbox. Power comes in one the left, through the large 25A isolating switches, before feeding to a pair of 30A contactors. The pair of outer relays next to the contactors are interlocks. These ensure that when one contactor is energized, the other is electrically locked out. Even if the interlock relay is manually operated with the orange flag visible on the top of the unit, they are wired to de-energize both contactors. This ensures that under no circumstances can both power sources be connected at the same time.
Panel Cutout
The generator controller requires a 68mmx68mm panel cutout for mounting. This was done in the main panel next to the electrical locker.
Box Fitted
Here the contactor board has been fitted into the wallbox & the cable glands fitted before wiring.
DKG-171System Online
The generator controller fitted & finally energized. The indicator LEDs on the front of the unit let the user know where power is currently being supplied from & which contactor is energized.
These speakers are available free from Pringles, with two packs bought. Normally running on 3x AAA cells, I have made modifications to include a high capacity Li-Ion battery & USB charging.
18650 Battery
New battery is 3x 18650 Li-Ion cells in parallel, providing ~6600mAh of capacity. These are hot glued inside the top of the tube under the speaker, with the charging & cell protection logic.
The battery charging logic is salvaged from an old USB eCig charger, these are single cell lithium chargers in a small form factor ideal for other uses. Charging current is ~450mA.
Amplifier Board
The cells are connected to the same points as the original AAA cells, with the other pair of wires going into the top of the device to connect to the MicroUSB charging port.
The amplifier in this is a LM4871 3W Mono amplifier IC, connected to a 6Ω 1W speaker.
The other IC on the board is unidentifiable, but provides the flashing LED function to the beat of the music.
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.
Progress is finally starting on the power supply unit for the Pi, fitted into the same case style as the Pi itself, this is an 8Ah Li-Poly battery pack with built in voltage regulation.
Regulator Boards
Here are the regulators, fixed to the top of the enclosure. These provide the 12v & 5v power rails for the Pi unit, at a max 3A per rail.
Battery Pack
In the main body of the case the battery pack is fitted. This is made up of 4 3-cell Li-Poly RC battery packs, rated at 2Ah each. All wired in parallel this will provide a total of 8Ah at 12.6v when fully charged.
Powered Up
Here the regulators are powered up from a 13v supply for testing. I have discovered at full load these modules have very bad ripple, so I will be adding extra smoothing capacitors to the power rails to compensate for this.
I/O
Here are the connectors on the top of the unit, outputting the two power rails to the Pi & the DC barrel jack that will be used to charge the pack.
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.
In preparation for my laser scanner project, I have modified my existing 445nm laser to accept a TTL blanking input. The laser driver is already enabled for this & just required an extra connection to interface with my laser scanner showboard. I have used an 8-pin connection to allow the same cable & interface to be used with an RGB laser system, when it arrives. The signals are as follows, from top centre, anti-clockwise:
Pin 1: +12v Power
Pin 2: Blue TTL
Pin3: GND
Pin 4: Green TTL
Pin 5: GND
Pin 6: Red TTL
Pin 7: GND
Centre: Power GND
Custom TTL Cable
Here is the custom 8 core cable, which connects to the laser scanner show board. This cable allows the laser to be used for projection while still retaining the portable function & the keylock arming switch. When plugged in the cable bypasses the keyswitch & provides 12v DC direct to the laser driver.
Having had a He-Ne laser tube for a while & the required power supply, it was time to mount the tube in a more sturdy manner. Above the tube is mounted with a pair of 32mm Terry Clips, with the power leads passing through the plastic top. The ballast resistor is built into the silicone rubber on the anode end of the tube. (Right).
Output power is about 1mW for this tube, which came from a supermarket barcode scanner from the 90’s. The tube is dated August 1993 & is manufactured by Aerotech.
Internals
Inside the box is the usual 2.2Ah 12v Li-Po battery pack & the brick type He-Ne laser supply. The small circuit in the centre is a switchmode converter that drops the 12v from the battery pack to the 5v required for the laser supply.
Here is a followup from the 1.5W laser module post.
The module has been fitted into a housing, with a 2.2Ah Li-Poly battery pack. Charging is accomplished with an external 12.6v DC power supply.
Above can be seen the pair of switches on the top, the keyswitch must be enabled for the laser to fire.
Armed
When armed, the ring around the push button illuminates blue, as a warning that the unit is armed.
Switch Wiring
Inside the unit. The Li-Poly battery pack is at the bottom, with it’s protection & charging circuitry on the top. The switches are wired in series, with the LED connected to illuminate when the keyswitch is turned to the ON position.
Laser Driver
The push button applies power to the laser driver module, which regulates the input power to safely drive the semiconductor laser in the aluminium heatsink housing.
There have been quite a few updates to the hosting solution for this site, which is hosted locally in my house, from the above setup, in a small comms rack, to a new 22U half rack, with some hardware upgrades to come.
Core Switch Disconnected
Core switch here has been removed, with the rest of the core network equipment. The site was kept online by a direct connection into the gateway to the intertubes.
Switching Gear Installed
New 22U rack, with the core switch, FC switch & management & monitoring server installed.
Router Going In
As I had no rack rails to start with, the servers were placed on the top of the rack to start off, here is the Dell PowerEdge 860 pfSense core router installed, with the initial switch wiring to get the internal core network back online. This machine load balances two connections for an aggregated bandwidth of 140MB/s downstream & 15MB/s upstream.
The tower server behind is the NAS unit that runs the backups of the main & auxiliary webservers.
Almost Done
Still with no rack kits, all the servers are placed on top of the rack, before final installation. This allows running of the network before the rest of the equipment was installed.
The main server & aux server are HP ProLiant DL380 G3 servers, with redundant network connections.
Still to arrive are the final rack kits for the servers & a set of HP BL20p Blade servers, which will be running the sites in the future.
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!
I thought this would be of interest, as it’s from a drive circa 2001, (DVD-CD-RW).
It’s the biggest & most complex optical block I’ve ever seen, with totally separate beam paths for the IR CD beam & the visible DVD beam. It also combines the use of bare laser diodes & combined diode/photodiode array modules for the pickup.
Cover Removed
Here’s a look at the optics inside the sled, on the left is a bare laser diode & photodiode array, for the CD reading, and the bottom right has the DVD combined LD/PD array module. The beam from the CD diode has to pass though some very complex beam forming optics & a prism to fold it round to the final turning mirror to the objective lens at top center.
There are also two separate photodiodes which are picking up the waste beam from the prisms, most likely for power control.
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.
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.
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