Here a tape is installed in the printer. This unit can handle tape widths up to 18mm. The pinch rollers are operated by the white lever at the top of the image, which engages with the back cover.
Li-Ion Battery
This printer is supplied with a rechargeable battery pack, but AA cells can be used as well. Some of the AA battery terminals can be seen above the battery.
Battery Specs
Pretty standard fare for a 2-cell lithium pack. The charging circuitry doesn’t appear to charge it to full voltage though, most likely to get the most life from the pack.
Cartridge Slot
With the cartridge removed, the printer components can be seen. As these cartridges have in effect two rolls, one fro the ribbon & one for the actual label, there are two drive points.
Pinch Rollers & Print Head
The thermal print head is hidden on the other side of the steel heatsink, while the pinch rollers are on the top right. The plastic piece above the print head heatsink has a matrix of switches that engage with holes in the top of the label cartridge, this is how the machine knows what size of ribbon is fitted.
Mainboard
Most of the internal space is taken up by the main board, with the microprocessor & it’s program flash ROM top & centre.
Charger Input
The charger input is located on the keyboard PCB just under the mainboard, which is centre negative, as opposed to 99% of other devices using centre positive, the bastards.
LCD Module
The dot-matrix LCD is attached to the mainboard with a short flex cable, and from the few connections, this is probably SPI or I²C.
Print Mech Drive
The printer itself is driven by a simple DC motor, speed is regulated by a pair of photo-interrupters forming an encoder on the second gear in the train.
Battery Holder Connections
The back case has the battery connections for both the lithium pack & the AA cells, the lithium pack has a 3rd connection, probably for temperature sensing.
Here’s the biggest portable USB powerbank I’ve seen yet – the PowerAdd Pilot X7, this comes with a 20Ah (20,000mAh) capacity. This pack is pretty heavy, but this isn’t surprising considering the capacity.
USB Ports & LED
The front of the pack houses the usual USB ports, in this case rated at 3.4A total between the ports. There’s a white LED in the centre as a small torch, activated by double-clicking the button. A single click of the button lights up the 4 blue LEDs under the housing that indicate remaining battery capacity. Factory charging is via a standard µUSB connector in the side, at a maximum of 2A.
PCB Front
The front of the PCB holds the USB ports, along with most of the main control circuitry. At top left is a string of FS8025A dual-MOSFETs all in parallel for a current carrying capacity of 15A total, to the right of these is the ubiquitous DW01 Lithium-Ion protection IC. These 4 components make up the battery protection – stopping both an overcharge & overdischarge. The larger IC below is an EG1501 multi-purpose power controller.
This chip is doing all of the heavy lifting in this power pack, dealing with all the DC-DC conversion for the USB ports, charge control of the battery pack, controlling the battery level indicator LEDs & controlling the torch LED in the centre.
EG1501 Example
The datasheet is in Chinese, but it does have an example application circuit, which is very similar to the circuitry used in this powerbank. A toroidal inductor is nestled next to the right-hand USB port for the DC-DC converter, and the remaining IC next to it is a CW3004 Dual-Channel USB Charging Controller, which automatically sets the data pins on the USB ports to the correct levels to ensure high-current charging of the devices plugged in. This IC replaces the resistors R3-R6 in the schematic above.
The DC-DC converter section of the power chain is designed with high efficiency in mind, not using any diodes, but synchronous rectification instead.
PCB Back
The back of the PCB just has a few discrete transistors, the user interface button, and a small SO8 IC with no markings at all. I’m going to assume this is a generic microcontroller, (U2 in the schematic) & is just there to interface the user button to the power controller via I²C.
Cells
Not many markings on the cells indicating their capacity, but a full discharge test at 4A gave me a resulting capacity of 21Ah – slightly above the nameplate rating. There are two cells in here in parallel, ~10Ah capacity each.
XT60 Battery Connector
The only issue with powerbanks this large is the amount of time they require to recharge themselves – at this unit’s maximum of 2A through the µUSB port, it’s about 22 hours! Here I’ve fitted an XT60 connector, to interface to my Turnigy Accucell 6 charger, increasing the charging current capacity to 6A, and reducing the full-charge time to 7 hours. This splits to 3A charge per cell, and after some testing the cells don’t seem to mind this higher charging current.
Battery Connector Wiring
The new charging connector is directly connected to the battery at the control PCB, there’s just enough room to get a pair of wires down the casing over the cells.
Here’s an oddity from the 1980’s – a CRT-based portable TV, with a very strangely shaped tube. Sony produced many types of flat CRTs back in the 80’s, with the electron gun at 90° to the curved phosphor screen.
Front Panel
The front panel has the display window, along with the tuning & volume indicators. Unfortunately since analogue TV transmissions have long been switched off, this unit no longer picks up any transmissions off the air, but it can be modified to accept a composite video input.
Back Panel
The back panel has the battery compartment & the tilt stand.
Certification
The certification label reveals this unit was manufactured in May 1984, 32 years ago!
Spec. Label
Rated at 6v, ~2.1W this device uses surprisingly little power for something CRT based.
Battery Holder
The battery holder is a little unique, this plastic frame holds 4 AA cells, for a 6v pack.
Battery Compartment
The battery holder slots into the back of the TV, there’s also an extra contact that the service manual mentions is for charging, so I assume a rechargeable 6v battery pack was also available.
Front Panel Removed
Removing a pair of pin-spanner type screws allows the front glass & screen printed CRT surround to be removed. Not much more under here other than the pair of screws that retain the CRT in the front frame.
Back Cover Removed
Here’s the back cover removed, after unscrewing some very small screws. As per usual with Sony gear, the electronics is extremely compacted, using many flat flex cables between the various PCBs. The main PCB is visible at the back, this has all the deflection circuitry, RF tuner, Video IF, Audio IF, video amplifier & composite circuitry.
CRT Electron Gun & Flyback Transformer
Lifting up the main board reveals more PCBs – the high voltage section for the CRT with the flyback transformer, focus & brightness controls is on the left. The loudspeaker PCB is below this. The CRT electron gun is tucked in behind the flyback transformer, it’s socket being connected to the rest of the circuitry with a flat flex cable.
CRT Rear
Here’s the back of the CRT, the phosphor screen is on the other side of the curved glass back. These tubes must require some additional deflection complexity, as the geometry will change as the beam scans across the screen. There’s a dynamic focus circuit on the schematics, along with extensive keystone adjustments.
Sony 02-JM Flat CRT
Here’s the tube entirely extracted from the chassis. The EHT connection to the final anode is on the side of the tube bell, the curved phosphor screen is clearly visible. The one thing I can’t find in this CRT is a getter spot, so Sony may have a way of getting a pure enough vacuum that one isn’t required.
I’d expect the vertical deflection waveforms to be vastly different on this kind of CRT, due to the strange screen setup. Not much of a beam movement is required to move the spot from the top to the bottom of the screen.
HV Module
No doubt to keep the isolation gaps large, all the high voltages are kept on a separate small PCB with the flyback transformer. This board generates the voltages for the electron gun filament, focus grid & the bias to set the beam current (brightness) as well.
Bare CRT
Here the deflection yoke has been removed from the CRT, showing the very odd shape better. These tubes are constructed of 3 pieces of glass, the bell with electron gun, back glass with phosphor screen & front viewing window glass. All these components are joined with glass frit.
Electron Gun
The electron gun in the neck looks to be pretty much standard, with all the usual electrodes.
Viewing Window
Here’s a view from the very top of the CRT, the curve in the screen is very obvious here. The electron beam emerges from the bell at the back.
FD-20 Schematic
Here’s the full schematic of the entire TV, I extracted this from a service manual I managed to find online.
More to come on hacking this unit to accept a standard composite video input, from something such as a Raspberry Pi!
Since the 4×18650 battery pack supplied with my Cree head torch is pretty shit, even by China’s standards, I figured something I could put my own cells into would be a better option. An eBay search turned up these battery boxes, not only with a direct battery output for my torch, but also a USB port for charging other devices when I’m low on charge.
LED Capacity Indicator
The output to the lamp connector is directly connected to the battery, through the usual Lithium Ion protection, but the USB output is controlled from a single power button. Battery charge condition is displayed on 3 LEDs. Not sure why they used blue silicone for the seal & then used green LEDs… But it does work, even if a little dim.
Label
Essential information. Does claim to be protected, and from the already existing electronics for the USB this would be expected in all but the cheapest crap.
An IP rating of IPX4 is claimed, yet just above that rating is a notice not to be used in water. Eh?
This is sealed with an O-Ring around the edge of the top cap & silicone seals around the cable & retaining screw. I did test by immersion in about 6″ of water, and it survived this test perfectly fine, no water ingress at all.
Interconnect Straps
The casing holds a PCB at the bottom end with the cell straps.
Screw Post
Someone wasn’t that careful at getting the brass screw insert properly centred in the injection mould when they did this one. It’s mushed off centre, but i’s solidly embedded & doesn’t present any problems to usability.
Cell Springs
The top cover holds the cell springs & the electronics.
Button & Cable Seal
Removing the pair of screws allows the top cap to open up. The cable, button & LEDs are robustly sealed off with this silicone moulding.
Top Removed
Here’s the PCB, not much on the top, other than the power button & battery indicator LEDs.
Electronics
Desoldering the cell springs allows the PCB to pop out of the plastic moulding. There’s more than I expected here!
Bottom left is a DC-DC converter, generating the +5v rail for the USB port, this is driven with an XL1583 3A buck converter IC.
Bottom right is the protection IC & MOSFETs for the Lithium Ion cells. I wasn’t able to find a datasheet for the tiny VA7022 IC, but I did manage to make certain it was a 7.4v Li-Ion protection IC.
Top right is a completely unmarked IC, and a 3.3v SOT-23 voltage regulator. I’m assuming that the unmarked IC is a microcontroller of some sort, as it’s handling more than just the battery level LEDs.
A pretty decent 4-core cable finishes the job off. For once there’s actually some copper in this cable, not the usual Chineseuim thin-as-hair crap.
The Dyson DC16 is one of the older handheld vacuums, before the introduction of the “Digital Motor”. (Marketing obviously didn’t think “Switched Reluctance Motor” sounded quite as good).
These vacuums have a very large DC brush motor driving the suction turbine instead, the same as would be found in a cordless power tool.
Control PCB
Popping the front cap off with the ID label, reveals the brains of the vacuum. The two large terminals at the right are for charging, which is only done at 550mA (0.5C). There are two PIC microcontrollers in here, along with a large choke, DC-DC converter for supplying the logic most likely. The larger of the MCUs, a PIC16HV785, is probably doing the soft-start PWM on the main motor, the smaller of the two, a PIC16F684 I’m sure is doing battery charging & power management. The motor has a PCB on it’s tail end, with a very large MOSFET, a pair of heavy leads connect directly from the battery connector to the motor.
Just out of sight on the bottom left edge of the board is a Hall Effect Sensor, this detects the presence of the filter by means of a small magnet, the vacuum will not start without a filter fitted.
Battery Pack
The battery pack is a large custom job, obviously. 4 terminals mean there’s slightly more in here than just the cells.
Battery Cracked
Luckily, instead of ultrasonic or solvent welding the case, these Dyson batteries are just snapped together. Some mild attack with a pair of screwdrivers allows the end cap to be removed with minimal damage.
Cells
The cells were lightly hot-glued into the shell, but that can easily be solved with a drop of Isopropanol to dissolve the glue bond. The pack itself is made up of 6 Sony US18650VT High-Drain 18650 Li-Ion cells in series for 21.6v nominal. These are rated at a max of 20A discharge current, 10A charge current, and 1.3Ah capacity nominal.
There’s no intelligence in this battery pack, the extra pair of terminals are for a thermistor, so the PIC in the main body knows what temperature the pack is at – it certainly gets warm while in use due to the high current draw.
Motor
Hidden in the back side of the main body is the motor. Unfortunately I wasn’t able to get this out without doing some damage, as the wiring isn’t long enough to free the unit without some surgery.
Turbine
The suction is generated by a smaller version of the centrifugal high-speed blowers used in full size vacuums. Not much to see here.
Unofficial Charger
Since I got this without a charger, I had to improvise. The factory power supply is just a 28v power brick, all the charging logic is in the vacuum itself, so I didn’t have to worry about such nasties as over-charging. I have since fitted the battery pack with a standard Li-Po balance cable, so it can be used with my ProCell charger, which will charge the pack in 35 minutes, instead of the 3 hours of the original charger.
In the past, I’ve used RC type LiPo packs for my mobile power requirements, but these tend to be a bit bulky, since they’re designed for very high discharge current capability – powering large motors in models is a heavy job.
I recently came across some Samsung Galaxy Tab 10.1 battery packs on eBay very cheaply, at £2.95 a piece. For this price I get 6800mAh of capacity at 4.2v, for my 12v requirements, 3 packs must be connected in series, for a total output of 12.6v fully charged.
For an initial pack, I got 9 of these units, to be connected in 3 sets of 3 to make 20Ah total capacity.There are no control electronics built into these batteries – it’s simply a pair of 3400mAh cells connected in parallel through internal polyfuses, and an ID EEPROM for the Tab to identify the battery.
This means I can just bring the cell connections together with the original PCB, without having to mess with the welded cell tabs.
Battery Pack
Here’s the pack with it’s cell connections finished & a lithium BCM connected. This chemistry requires close control of voltages to remain stable, and with a pack this large, a thermal runaway would be catastrophic.
Cell Links
The OEM battery connector has been removed, and my series-parallel cell connections are soldered on, with extra lead-outs for balancing the pack. This was the most time-consuming part of the build.
If all goes well with the life of this pack for utility use, I’ll be building another 5 of these, for a total capacity of 120Ah. This will be extremely useful for portable use, as the weight is about half that of an equivalent lead-acid.
Thanks to Lewis over at Distant Signal Radio, the bad influence he is on my bank balance ;), I’m the proud new owner of a new Baofeng. This time it’s the UV-82.
This radio is a little different from the other Baofengs I have. Here are the main differences:
Dual PTT – This one is going to take some getting used to 😉
Higher capacity battery pack
A more rugged, commercial feel
This radio has a different method of selecting the VFO mode – holding the menu key while the unit is powered on. This is a little awkward, but since I only usually use my local repeaters when I’m mobile, it’s not much of an issue.
UV-82
Here’s the radio itself, it has a much more commercial feel to it than the UV-5Rs, and it’s slightly bigger. Mainly due to the use of a larger standard battery & larger loudspeaker.
Spec Label
Back of the unit with the spec label. As per usual Baofeng are a bit conservative with the power ratings, more to come on that below.
Battery Pack
Here’s the battery pack, a 2-cell lithium-polymer unit. This has a bigger capacity than the standard UV-5R battery, at 2800mAh.
Here are the power settings as measured by my GY-561. Frequencies used are 145.500 & 433.500
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 original LM2577 based regulators I designed into my mobile battery pack turned out to be insufficient for requirements, therefore they have been replaced with higher capacity regulators.
The 12v regulator (left) is a muRata UQQ-12/8-Q12P-C SEPIC converter, providing a max of 8A at 12.1v DC. The 12v rail is also now independently switchable to save power when not in use.
The 5v regulator (right) is a Texas Instruments PTN78020WAZ switching regulator, rated at 6A. The pair of resistors on the back of the regulator set the output voltage to 5.1v.
Also a new addition is a pair of banana sockets & a 2.1mm DC jack, wired into the 12v DC bus, for powering various accessories.
New Additions
Below the USB sockets is now a built in eCig charger, to save on USB ports while charging these devices.
IWA National Festival 2013
These changes were made after much field testing of the unit at Cassiobury Park, Watford, for the IWA National Waterways Festival.
I have acquired a 24W monocrystalline solar panel to charge my portable battery pack while on the move. This panel will be able to charge all devices I carry on a regular basis with nothing but some sunlight!
Info Panel
Info on the panel itself. Rated at 24W with nominal 17.6v DC, 1.36A output.
Regulator
I have installed a switching regulator in the back of the panel, where the connections would normally be wired straight to the array of cells. This regulates the voltage down to a constant 13.8v to provide more compatibility with 12v charging equipment. I have tested the output of the panel in late day sun, at 1.27A.
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.
The final part for the battery pack has finally arrived, the PCM boards. These modules protect the cells by cutting off the power at overcharge, undercharge & overcurrent. Each cell is connected individually on the right, 12v power appears on the left connections. These modules also ensure that all the cells in the pack are balanced.
A few modifications were required to the SMPS modules to make the power rails stable enough to run the Pi & it’s monitor. Without these the rails were so noisy that instability was being caused.
I have replaced the 100µF output capacitors & replaced them with 35v 4700µF caps. This provides a much lower output ripple.
There are also heatsinks attached to the converter ICs to help spread the heat.
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.
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.
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.
5v Regulator
The 7.5v rail also provides power to this Texas Instruments PTH08000 switchmode regulator module, providing the 5v rail for the USB port power.
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.
Front Panel Right
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.
Front Panel Left
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!
Here is a Bosch 14.4v Professional cordless drill/driver, recovered from a skip!
It was thrown away due to a gearbox fault, which was easy to rectify.
Internals
Here is the drill with the side cover removed, showing it’s internal parts. The speed controller is below the motor & gearbox here. The unit at the top consists of a 12v DC motor, coupled to a 4-stage epicyclic gearbox unit, from which can be selected 2 different ratios, by way of the lever in the centre of the box. This disables one of the gear stages. There is a torque control clutch at the chuck end of the gearbox, this was faulty when found.
Motor
Here is the drive motor disconnected from the gearbox, having a bayonet fitting on the drive end.
Drive Gear
This is the primary drive gear of the motor, which connects with the gearbox.
Cooling Fan
The motor is cooled by this fan inside next to the commutator, drawing air over the windings.
Gearbox
This is the gearbox partially disassembled, showing the 1st & second stages of the geartrain. The second stage provides the 2 different drive ratios by having the annulus slide over the entire gearset, disabling it entirely, in high gear. The annulus gears are a potential weak point in this gearbox, as they are made from plastic, with all other gears being made of steel.
Charger
Here is the charging unit for the Ni-Cd battery packs supplied with the drill. The only indicator is the LED shown here on the front of the unit, which flashes while charging, & comes on solid when charging is complete. Charge termination is by way of temperature monitoring.
Transformer
Here the bottom of the charger has been removed, showing the internal parts. An 18v transformer supplies power to the charger PCB on the left.
Charger PCB
This is the charger PCB, with a ST Microelectronics controller IC marked 6HKB07501758. I cannot find any information about this chip.
Battery Pack Internals
Here is a battery pack with the top removed, showing the cells.
Temperature Sensor
This is the temperature sensor embedded inside the battery pack that is used by the charger to determine when charging is complete.
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