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BluVision Bluetooth Low Energy Beacon

Violent Disassembly
Violent Disassembly

These photos were sent over to me by a friend, an interesting piece of tech that’s used in the retail industry. This is a BluVision BLE Beacon, which as far as I can tell is used to provide some automated customer assistance. From their website it seems they can also be used for high-price asset protection & tracking. These units don’t appear to be serviceable, being completely sealed & only having a primary cell. I’m not sure what they cost but it seems to be an expensive way to contact clients with adverts etc.

Component Side
Component Side

There’s not much populated on this PCB, the main component here is the CC2640 SimpleLink ultra-low-power wireless microcontroller for Bluetooth Low Energy. It’s a fairly powerful CPU, with an ARM Cortex M3 core, 129KB of flash & up to 48MHz clock speed. There’s a couple of crystals, one of which is most likely a 32,768kHz low-power sleep watch crystal, while the other will be the full clock frequency used while it’s operating. Unfortunately I can’t make the markings out from the photos. There doesn’t appear to be any significant power supply components, so this must be running direct from the battery underneath.

2.2Ah 3.6v Lithium Cell
2.2Ah 3.6v Lithium Cell

The other side of the PCB has a single primary lithium cell, rated at 3.6v, 2.2Ah. The factory spec sheet specifies a 2.2 year life at 0dBm TX Power, Running 24/7, 100ms advertisement rate.

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103RS GPS Tracker Teardown

Rewire Security 103RS Tracker
Rewire Security 103RS Tracker

I thought it was time to add a bit of security to the gear I take camping, so this GPS tracker unit was sourced from eBay. This is a Rewire Security 103RS, a slightly customised version of the common Chinese TK103 GPS tracker.

Input Connections
Input Connections

The small module has all it’s power connections on one end of the unit, on a Molex multi-way block. The white connector is for a piezo-shock sensor – this interfaces with the alarm functionality of the unit. There’s an indicator LED for both the GPS & GSM status, and a switch for the backup battery.

Antenna Connections
Antenna Connections

The other end has the antenna connections, microphone connection for the monitor function, along with the SIM & SD card slots.

PCB Top
PCB Top

Once the end panel is removed, the PCB just slides out of the aluminium extruded casing. It’s pretty heavily packed with components in here. A switching regulator deals with the 12v input from the vehicle battery, and is protected by a polyfuse on the right. The GSM module is hiding under the Li-Po backup cell, unfortunately the sticky pad used to secure this wouldn’t come off without damaging something. The pigtails for both the GPS & GSM antennas are permanently soldered to the board here.

PCB Bottom
PCB Bottom

The bottom of the PCB has the GPS module, and mainly input protection & bypassing components. There is a FNK4421 Dual P-Channel MOSFET here as well, probably used for switching the external relay or alarm siren. The SIM socket for the GSM modem is located here in the corner.

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Tenma 72-10405 DMM Teardown

Tenma DMM
Tenma DMM

Well it’s time for a new DMM. After the last pair of eBay El-Cheapo Chinese meters just didn’t last very well, I decided a proper meter was required. This one is a Tenma 72-10405, stocked by Farnell for under £60. Not quite as many festures as the cheapo Chinese meters, but I expect this one to be a bit more reliable.

PCB Rear
PCB Rear

Since I can’t have anything without seeing how it’s put together, here’s the inside of the DMM. (Fuse access is only possible by taking the back cover off as well. The 9v PP3 battery has a seperate cover).

PCB Rear Bottom
PCB Rear Bottom

He’s the input section of the meter, with the 10A HRC fuse & current shunt for the high-amps range. The other fuse above is for the mA/µA ranges. The back cover has a wide lip around the edge, that slots into a recess in the front cover, presumably for blast protection if the meter should meet a sticky end. The HRC fuses are a definite improvement over the cheap DMMs, they only have 15mm glass fuses, and no blast protection built into the casing.
There are some MOVs for input protection on the volts/ohms jack, the jacks themselves are nothing more than stampings though.

PCB Rear Top
PCB Rear Top

Not much at the other side of the board, there’s the IR LED for the RS232 interface & the beeper.

PCB Front
PCB Front

Most of the other components are on the other side of the PCB under the LCD display. The range switch is in the centre, while the main chipset is on the left.

DMM Chipset
DMM Chipset

The chipset of this meter is a FS9922-DMM3 from Fortune Semiconductor, this is a dedicated DMM chipset with built in ADCs & microcontroller.

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Eco-Light 4W LED Bulb Teardown

Components
Damaged Bulb
Damaged Bulb

Here’s a modern LED bulb, that unfortunately decided to disassemble itself within a few minutes of being installed in a light fitting! The base plastic snapped off the main aluminium body at the screw posts!

Input Rectifier
Input Rectifier

The PCB in the base holds nothing but the input components. Above is the bridge rectifier.

Fusible Resistor
Fusible Resistor

The other side of the PCB has a 10Ω fusible resistor, for protection.

LED PCB
LED PCB

The LED PCB itself has the driver IC, which is a CYT3000A linear constant current IC, that runs direct from full-wave rectified mains. The single resistor sets the LED current, but there aren’t any smoothing capacitors on the DC rail, so this bulb would flicker a lot.

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eBay High Voltage DC-DC Converter Module

High Voltage DC-DC
High Voltage DC-DC

Going through eBay recently looking for parts for a couple of CRT-based projects, I came across these DC-DC converters.
Apparently rated from 45-390v DC output at 200mA, these should be ideal for driving some of the electrodes (focus, screen, grid) in a CRT.
Above is the top of the board, input voltage header on the left, output voltage adjust in the centre & output voltage header on the right.
This module has a mini-automotive fuse, at 10A for input protection.
On the heatsink is mounted the main switching MOSFET, a RU7088R from Ruichips. This FET is fairly heavily rated at 70v 80A, with 6.5mΩ on-resistance.

PCB Bottom
PCB Bottom

The bottom of the board has the control components, with a pair of ICs. Unfortunately the numbers have been scrubbed off, so no identification here. The output from the transformer is rectified with a single large SMD diode on the left side of the board.
There’s also plenty of isolation gap between the HV output trace & the low voltage logic side of the circuit, the two being bridged only by a resistive divider for output voltage measurement.

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Multifunction LCD Power Meter MHF-8020P

LCD Unit
LCD Unit

I recently came across these on eBay, so I thought I’d grab one to see how they function, with all the metrics they display, there’s potential here for them to be very useful indeed.
One of the best parts is that no wiring is required between the sensor board & the LCD head unit – everything is transmitted over a 2.4GHz data link using NRF24L01 modules.
Above is the display unit, with it’s colour LCD display. Many features are available on this, & they appear to be designed for battery powered systems.

Monitor PCB
Monitor PCB

Another PCB handles the current & voltage sensing, so this one can be mounted as close to the high current wiring as possible.

Monitor PCB Microcontroller
Monitor PCB Microcontroller

The transmitter PCB is controlled with an STM8S003F3 microcontroller from ST Microelectronics. This is a Flash based STM with 8KB of ROM, 1KB of RAM & 10-bit ADC. The NRF24L01 transceiver module is just to the left.
There’s only a single button on this board, for pairing both ends of the link.

Output MOSFET
Output MOSFET

The high current end of the board has the 0.0025Ω current shunt & the output switch MOSFET, a STP75NF75 75v 75A FET, also from ST Microelectronics. A separate power source can be provided for the logic via the blue terminal block instead of powering from the source being measured.

LCD Unit Rear
LCD Unit Rear

Here’s the display unit, only a pair of power terminals are provided, 5-24v wide-range input is catered for.

LCD Unit PCB
LCD Unit PCB

Unclipping the back of the board reveals the PCB, with another 2.4GHz NRF24L01 module, and a STM8S005K6 microcontroller in this case. The switching power supply that handles the wide input voltage is along the top edge of the board.

Unfortunately I didn’t get any instruction manual with this, so some guesswork & translation of the finest Chinglish was required to get my head round the way everything works. To make life a little easier for others that might have this issue, here’s a list of functions & how to make them work.

LCD Closeup
LCD Closeup

On the right edge of the board is the function list, a quick press of the OK button turns a function ON/OFF, while holding it allows the threshold to be set.
When the output is disabled by one of the protection functions, turning that function OFF will immediately enable the output again.
The UP/DOWN buttons obviously function to select the desired function with the cursor just to the left of the labels. Less obviously though, pressing the UP button while the very top function is selected will change the Amp-Hours display to a battery capacity icon, while pressing DOWN while the very bottom function is selected will change the Watts display to Hours.
The round circle to the right displays the status of a function. Green for OK/ON Grey for FAULT/OFF.

  • OVP: Over voltage protection. This will turn off the load when the measured voltage exceeds the set threshold.
  • OPP: Over power protection. This function prevents a load from pulling more than a specified number of watts from the supply.
  • OCP: Over current protection. This one’s a little more obvious, it’ll disable the output when the current measured exceeds the specified limit.
  • OUT: This one is the status of the output MOSFET. Can also be used to manually enable/disable the output.
  • OFT: Over time protection. This one could be useful when charging batteries, if the output is enabled for longer than the specified time, the output will toggle off.
  • OAH: Over Amp-Hours protection. If the counted Amp-Hours exceeds the set limit, the output will be disabled.
  • Nom: This one indicates the status of the RF data link between the modules, and can be used to set the channel they operate on.
    Pairing is achieved by holding the OK button, selecting the channel on the LCD unit, and then pressing the button on the transmitter board. After a few seconds, (it appears to scan through all addresses until it gets a response) the display will resume updating.
    This function would be required if there are more than a single meter within RF range of each other.

I’ve not yet had a proper play with all the protection functions, but a quick mess with the OVP setting proved it was very over-sensitive. Setting the protection voltage to 15v triggered the protection with the measured voltage between 12.5v-13.8v. More experimentation is required here I think, but as I plan to just use these for power monitoring, I’ll most likely leave all the advanced functions disabled.

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IC Decap: Motorola XPC860PZP50D4 Communications Controller

XPC860PZP50D4 Package
XPC860PZP50D4 Package

This is a System On Chip from Motorola, designed for network routing applications. This chip contains a hell of a feature set, so I’ll just include an excerpt from the datasheet:

XPC860PZP50D4 Die
XPC860PZP50D4 Die

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Quickie Project: Ruggedising The RTL-SDR Dongle

As supplied, the RTL type tuner dongles are a little fragile, especially when they’ve got a rather heavy coax feeder attached for Ham Radio use.

The MCX antenna connectors on the tuner can’t stand up to much abuse, and even the USB plug rips itself from it’s mounts after a while with a heavy weight on the end. Since this dongle sits in my radio go bag, it definitely needed some protection & support.

PCB
PCB

The PCB itself is removed from it’s flimsy plastic casing, the USB plug is desoldered from the board.
To the exposed pads, a USB cable is soldered, giving much more flexibility in where the tuner is placed.
Instead of using the MCX antenna connector on the PCB, the coax is stripped & soldered direct to the PCB itself, as this connector has become unreliable.

N-Connector
N-Connector

To get the RF into the device, the case is fitted with an N connector, as is everything else in my shack.

Boxed
Boxed

The box used is a surplus one which previously housed an electronic lighting transformer. This would be very easy to waterproof as well, for more protection against outdoor use.

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Baofeng Battery Capacity Lies

I’ve had a couple of larger batteries for my UV-5Rs for some time now, and decided to do a quick teardown to see if they’re actually the capacity claimed.

BL-5L Battery
BL-5L Battery

Here’s the label, claiming 3800mAh (3.8Ah) of battery capacity.
These batteries are held together with glue, but a good way to get these kinds of things open is by whacking the seams with the handle of a screwdriver. This cracks the glue without damaging the casing.

Battery Cracked Open
Battery Cracked Open

After a few minutes of cracking the seams, the battery comes right open. The pair of wires link the protection board on the cells to the DC terminals on the top of the pack. The charging terminals are under the cardboard insulator on the right.

Cells
Cells

Here’s the other half of the case, with the cells themselves. These are wired in series for a 7.2v pack, and at a capacity of 2600mAh (2.6Ah) printed on them, the label clearly lies about the capacity.

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GY561 Frequency & Power Meter LiPo Conversion

From the factory, the GY561 meter uses alkaline AAA cells for power. As these are not rechargable, and I don’t carry any other devices that take such batteries, I figured I’d replace them with a single Lithium Polymer cell that I can charge via USB.

Battery Compartment
Battery Compartment

Here’s the battery compartment, with the original spring terminals removed.
I searched eBay for a suitable sized cell, and settled on a 1000mAh type, with dimensions of 47mm x 28mm x 7mm.

This size cell required a small amount of modification to the battery compartment to make it fit properly with the associated charge & protection circuitry.

Modified Compartment
Modified Compartment

Here’s the modifications made to the compartment, I’ve ground away the plastic to make the bottom flat, and the plastic tabs that retained the original spring terminals.

Modifications
Modifications

After grinding away the original battery spring holders with a dremel, the cell fits perfectly in the available space. The small PCB on the top of the cell is the USB charger & protection.

Charger
Charger

The charger is located in a slot cut in the bottom of the casing, so the USB port is accessible from outside the compartment.

Wiring
Wiring

Here’s the rest of the wiring completed, with the power wires going through holes in the bottom of the battery compartment to join onto the PCB where the original terminals were located. I have insulated the solder joints on the control PCB with some Kapton tape to prevent any shorts against the lithium cell.

Battery Cover
Battery Cover

A small cutout was also required in the battery cover to allow the USB connector to poke out. This was easy to do on the soft plastic with a Dremel tool.

Charging Port
Charging Port

With the battery cover installed, the USB port is nicely recessed into the edge.

Charging LED
Charging LED

The indicator LEDs on the charging & control board show nicely through the plastic, here’s the unit on charge. When the charge is complete, another LED lights as shown below.

Charging Complete
Charging Complete
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SainSmart Frequency Meter

Thanks to Lewis, M3HHY for lending me this one 🙂

Here’s a quick look at a Sainsmart frequency counter module. These are useful little gadgets, showing the locked frequency on a small LCD display.

It’s built around an ATMega328 microcontroller (µC), and an MB501L Prescaler IC. The circuit for this is very simple, and is easily traced out from the board.

Frequency Counter
Frequency Counter

Here’s the back of the board, with the µC on the left & the prescaler IC on the right. This uses a rather novel method for calibration, which is the trimmer capacitor next to the crystal. This trimmer varies the frequency of the µC’s oscillator, affecting the calibration.

Input protection is provided by a pair of 1N4148 diodes in inverse parallel. These will clamp the input to +/-1v.
The prescaler IC is set to 1/64 divide ratio. This means that for an input frequency of 433MHz, it will output a frequency of 6.765625MHz to the µC.

The software in the µC will then calculate the input frequency from this intermediate frequency. This is done because the ATMega controllers aren’t very cabable of measuring such high frequencies.

The calculated frequency is then displayed on the LCD. This is a standard HD44780 display module.

LCD
LCD

Power is provided by a 9v PP3 battery, which is then regulated down by a standard LM7805 linear regulator.

Readout
Readout

I’ve found it’s not very accurate at all at the lower frequencies, when I fed it 40MHz from a signal generator it displayed a frequency of around 74MHz. This is probably due to the prescaler & the software not being configured for such a low input. In the case for 40MHz input the scaled frequency would have been 625kHz.

 

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AD9850 DDS VFO PCB & Schematic Layout

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
DDS VFO

Version 2 Update: Added reverse polarity protection, added power indicator LED, beefed up tracks around the DC Jack.
[download id=”5571″]

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Pringles Speaker Modifications

USB Charging Port
USB Charging Port

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
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
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.

 

 

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1.5W 445nm Lab Laser

Assembled
Assembled

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
Armed

When armed, the ring around the push button illuminates blue, as a warning that the unit is armed.

Switch Wiring
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
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.

 

 

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ModMyPi Raspberry Pi Case

Fitted Pi
Fitted Pi

Finally, some protection for my Raspberry Pi! The PCB fit is slightly loose, but that was quickly sorted with the application of a couple of spots of hot glue in the corners.

Unfortunately, the case is a couple of mm too small to fit the main board from the Pico Projector inside, so I won’t be butchering that into the case with the Pi as yet. What is required is an interface to the display engine from the Pi’s DSI interface.

 

Pi Cased Up
Pi Cased Up

The pi all boxed. up. The only thing that this case would now require is a lightpipe to direct the LED’s light to the openings in the case, as they are very difficult to see at present.

 

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532nm DPSS Module

DPSS Module
DPSS Module

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

Diode Connection
Diode Connection

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

Driver PCB
Driver PCB

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

Output
Output

Output beam from the module.

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Portable Power Pack Charger

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

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

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Nokia 7110

Front
Front

Another phone from the mid 90s. This is the nokia 7110.

Slider Open
Slider Open

Here the slider is open showing the keypad.

Battery Removed
Battery Removed

Here the battery is removed, a Li-Ion unit.

Battery
Battery

The battery cell & protection circuit removed from the casing.

Rear Of PCB
Rear Of PCB

This is the rear of the PCB removed from the housing. Data & charging ports on the right hand side f the board.

Front Of PCB
Front Of PCB

Front of the PCB with the RF sections at the left hand side & the keypad contacts on the right.

RF Sections
RF Sections

Closeup of the RF sections of the board, big silver rectangular cans are VCO units.

SIM Connector
SIM Connector

Closeup of the top rear section of the PCB, with SIM cnnector, battery contacts, IR tranciever at the far left. Bottom centre is the external antenna connector.

CPU
CPU

The logic section of the board, Large chip is CPU, to right of that is the ROM storing the machine code. Other chips are unknown custom parts.

Mic & Speaker
Mic & Speaker

The Mic & the loudspeaker removed from it’s housing.

LCD
LCD

LCD from the front of the unit, SPI interfaced. Flex PCB also contains the power button, loudspeaker contacts & a temperature sensor.

Scroll Wheel
Scroll Wheel

The scroll wheel removed from the front housing.

Vibra-Motor
Vibra-Motor

Tiny vibration motor removed from the rear housing, alerts the user to a text or phone call.