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UM25C USB Power Meter

UM25C USB Power Meter
UM25C USB Power Meter

Here’s a nice little feature-packed USB power meter, the UM25C. This unit has USB-C along with the usual USB type A connectors, along with a bluetooth radio for remote monitoring of stats via a Windows or Android app. Construction is nice, it’s a stack of two PCBs, and polycarbonate cover plates, secured together with brass posts & screws.

Back Cover
Back Cover

The back cover has the legend for all the side connectors, along with the logo.

USB Micro Input
USB Micro Input

Down the sides are the user interface buttons, and here the Micro-B input connector. The 4-pin header is visible here that takes serial data down to the bluetooth section.

USB-C Connectors
USB-C Connectors

The other side has the remaining pair of buttons, and the USB-C I/O. I don’t yet own anything USB-C based, but this is good future proofing.

LCD Display
LCD Display

Removing the top plastic cover plate reveals the small 1″ TFT LCD module. This will be hot-bar soldered underneath the screen. There’s an unused footprint next to the USB input connector, judging by the pin layout it’s probably for a I²C EEPROM.

Main Board Components
Main Board Components

The underside of the top PCB has all the main components. The brains of the operation is a ST STM8S005C6T6 microcontroller. It’s at the basic end of the STM range, with a 16MHz clock, 32K flash, EEPROM, 10-bit ADC, SPI, UART & I²C. The main 0.010Ω current shunt is placed at the top left of the board in the negative rail. A couple of SOT-23 components in the centre of the board, I haven’t been able to identify properly, but I think they may be MOSFETs. The large electrolytic filter capacitor has a slot routed into the PCB to allow it to be laid flat. Providing the main power rail is a SOT-89 M5333B 3.3v LDO regulator.

Bluetooth Radio
Bluetooth Radio

The bottom board contains the bluetooth radio module, this is a BK3231 Bluetooth HID SoC. The only profile advertised by this unit is a serial port. There’s a local 3.3v LDO regulator & support components, along with an indicator LED.

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Wheelchair Motors Part 2: Service

Cleaning, Replacement Parts & Reassembly

Housing Cleaned
Housing Cleaned

The housing of the contaminated motor was left to soak in diesel for a few hours to loosen the grok, this has come very clean. I couldn’t have used a stronger solvent here – the magnets are glued in place in the steel housing, I certainly didn’t want them coming loose!

Brushboxes
Brushboxes

Next into the diesel bath are the motor end bells with the brushgear. Attack with a stiff brush cleaned these up very well, some cotton buds served to clean out the brass brush holders.

Armatures After Skimming
Armatures After Skimming

Here are both armatures, having had their commutators resurfaced. I’ve completely removed all traces of the wear caused by the contamination, luckly the commutator bars are very heavy on these motors so can take quite a bit of wear before there’s not enough left to skim. I’ve not yet pulled off the old bearings, but they are all going to be replaced with new SKF bearings, as they’ve been contaminated with grok over the years of use. I’m also going to uprate the front motor bearings to rubber sealed instead of metal shielded, to help keep lubricant out of the motors if the gearbox seals ever fail again.

Gearbox
Gearbox

The gearboxes have been cleaned out with some elbow grease, assisted by a long soak in petrol, I’ve refilled them here with engine oil as temporary lube & to flush out the last remains of the old grease & solvent. The worm wheel in these boxes is bronze – so a GL4 gear oil will be required. (Some Extreme Pressure additive packs contain sulphur, and will readily attack copper alloys, such as brass & bronze).

Commutator End Bearings
Commutator End Bearings

Here’s the armatures, after the new SKF sealed bearings have been fitted to the commutator end, above, and the drive end, below. These will cause some extra drag on the armatures, and slightly higher power consumption as a result, but keeping the crap out of the motors is slightly more important.

Drive End Bearings
Drive End Bearings
Fresh Commutator Skim
Fresh Commutator Skim

The commutators have been lightly skimmed with abrasive cloth, and finished with 1500 grit emery. The armature on the right has been run for a short time to see how the new brushes are bedding in.

Old Seal Removed
Old Seal Removed

Finally, the old oil seals are pulled from the gearboxes. The worm gear bearing on the inside is actually a sealed version, with the external oil seal providing some extra sealing. I haven’t changed the gearbox bearings, as they seem to be in good order, this might get done at some point in the future.

New Oil Seals
New Oil Seals

The new seals ready to be driven into the bores.

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Boat Stuff: Bowman Oil Cooler

Bowman Oil Cooler
Bowman Oil Cooler

To solve some engine oil overheating problems on board nb Tanya Louise, we decided to replace the air-over-oil cooler, with an water-over-oil cooler, with separate cooling drawn straight from the canal, as the skin tanks are already overloaded with having to cope with not only cooling the engine coolant, but also the hydraulic system oil as well.
These units aren’t cheap in the slightest, but the construction quality & engineering is fantastic.

Tube End Plate
Tube End Plate

Unbolting the end cover reveals the brass tube end plate, soldered to all the core tubes in the cooler. An O-Ring at each end seals both the end cover & the interface between the tube plate & the outer casing.

End Caps
End Caps

The end caps have baffles cast in to direct the cooling water in a serpentine path, so the oil gets the best chance at dissipating it’s heat to the water.

Tube Stack
Tube Stack

The oil side of the system is on the outside of the tubes, again baffles placed along the stack direct the oil over the highest surface area possible.

Outer Shell
Outer Shell

The outer shell is just a machined alloy casting, with no internal features.

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Pilot LPG Monitoring System

Pilot Gas Monitor
Pilot Gas Monitor

In my mind, the most dangerous thing onboard any boat is the LPG system, as the gas is heavier than air, any leaks tend to collect in the bilges, just waiting for an ignition source. To mitigate this possibility, we’re fitting a gas monitoring system that will sound an alarm & cut off the supply in case of a leak.

Monitor Unit
Monitor Unit

Here’s the monitor itself, the two sensor model. It’s nice & compact, and the alarm is loud enough to wake the dead.

Control Board
Control Board

Not much inside in the way of circuitry, the brains of the operation is a Microchip PIC16F716 8-bit microcontroller with an onboard A/D converter (needed to interface with the sensors), running at 4MHz. The solenoid valve is driven with a ULN2803 Darlington transistor array.
The alarm Piezo sounder can be seen to the right of the ICs, above that is a simple LM7805 linear regulator providing power to the electronics.

Remote Sensor
Remote Sensor

The pair of remote sensors come with 3.5m of cable, a good thing since the mounting points for these are going to be rather far from the main unit in our installation.

Sensor Element
Sensor Element

The sensor itself is a SP-15A Tin Oxide semiconductor type, most sensitive to butane & propane. Unlike the Chinese El-Cheapo versions on eBay, these are high quality sensors. After whiffing some gas from a lighter at one of the sensors, the alarm triggered instantly & tripped the solenoid off.

Solenoid Valve
Solenoid Valve

The solenoid valve goes into the gas supply line after the bottle regulator, in this case I’ve already fitted the adaptors to take the 10mm gas line to the 1/2″ BSP threads on the valve itself. This brass lump is a bit heavy, so support will be needed to prevent vibration compromising the gas line.

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Camping Gear – Optimus Nova Multifuel Stove

Stove
Stove

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

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

Burner
Burner

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

Fuel Pump
Fuel Pump

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

Pre-Heating
Pre-Heating

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

Simmer
Simmer

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

Full Power!
Full Power!

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

Flame Pattern
Flame Pattern

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

Fuel Jet
Fuel Jet

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

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Lethal Chinese Mains Adaptors

With every piece of Chinese electronics I obtain, mainly Baofeng radios, they come with a Europlug-type power adaptor, and a universal plug adaptor for the mains.

The charger units aren’t too bad, there’s a fair amount of isolation between the primary & secondary, and even though they’re very simple & cheap, I can’t see any immediate safety problems with them.

The plug adaptors, however, are a different matter. These things are utterly lethal!

Baofeng PSU
Baofeng PSU

Here’s the inside of the PSU. It’s just a very simple SMPS, giving an output of 10v 500mA. The fuse is actually a fusible resistor.

PCB Reverse
PCB Reverse

Here’s the back of the PCB with the SMPS control IC. I can’t find any English datasheets for this part unfortunately.

Universal Travel Adaptor
Universal Travel Adaptor

Here’s the dangerous adaptor. There’s no safety shield, so the live parts are exposed.

Internals
Internals

Here’s the adaptor split apart. The output contacts are on the left, and rely just on pressure to make contact with the brass screws on the mains input pins to provide power.
This is a very poor way to get a connection, a dirty or worn contact here would create a lot of heat if any significant power is pulled through, and could quite possibly result in a fire.

Not surprisingly, I bin these things as soon as I open the box, and charge all my radios with a 12v charging system.

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Zebra P330i Card Printer

Front
Front

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
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
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
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
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
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
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
LCD

 

 

 

 

Front of the LCD, this is white characters on a blue background.

Roller Drive Belts
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
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
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
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
Power Supply

 

 

 

Here is the main power supply, a universal input switch-mode unit, outputting 24v DC at 3.3A.

PSU Label
PSU Label

 

 
PSU info. This is obviously an off the shelf unit, manufactured by Hitek. Model number FUEA240.

Print Engine Rear
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
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
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
I/O Daughterboard

 

 

 

 

 

The I/O daughterboard connects to the main CPU board & interfaces all the motors & sensors in the printer.

Main PCB
Main PCB

Here is the main CPU board, which contains all the logic & processing power in the printer.

CPU
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
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
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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XM2000 Marine VHF Radio

Radio
Radio

Here is an old XM2000 marine VHF tranciever.

Internal View
Internal View

Here is the casing split, with the main CPU board & display on the right, & the RF tranciever board on the left.

Main CPU
Main CPU

View of the main CPU board, with the mic & loudspeaker on the right hand side.
The channel display is on the reverse side of the PCB.

RF Board
RF Board

View of the RF board, with it’s brass shielding attached. This radio will transmit at 5W max.

RF Shields Removed
RF Shields Removed

Shielding removed, power regulation bottom right corner of the board, tranciever on the left.

PCB Front
PCB Front

CPU board removed from the casing, showing the LCD & the user buttons to the left.

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Audi TT Roof Hydraulics

Pump
Pump

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

Cylinders
Cylinders

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

Limit Switch
Limit Switch

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

Hose
Hose

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

Motor
Motor

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

Motor Suppression
Motor Suppression

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

Reversing Relays
Reversing Relays

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

Tank
Tank

Detail of the oil tank showing the level markings.

Power Valve
Power Valve

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

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Motorised Valve

This is the internals of a motorised valve for central heating systems. Here the top is removed showing the motor & microswitch.

Left side of the valve, showing the gearing under the motor, & the valve body under the powerhead.

Right side of the valve, showing the sprung mechanism of the valve quadrant.

Here the motor has been removed from the powerhead, showing the microswitch & the sprung quadrant gear. This spring keeps the valve closed until the motor is energized. The motor remains energized to hold the valve open.

Here the valve body has been opened showing the internal components. The rubber valve rotates on the shaft, blocking the lower port of the valve when in operation.

The motor’s protective cap has been removed here showing the rotor. This is a synchronous motor, of a special type for use in motorised valves. As the windings need to be continuously energized to hold the valve open, it is designed not to burn out under this load. 240v AC 50Hz, 5RPM.