Sunday, August 16, 2020

ids ueye re (harsh environments) connector pinouts (usb) and a fix repair job

ids re (harsh environments) version
has a special ip rated connectors
didnt want to buy an expensive cable 
and pins were compatible with female jumper wire
so just traced the pinouts and connected

see color dot next to the pins
center top pin left unconnected



and a small repair job
malfunction dc dc converter by texas instruments AIO
replaced by an ams11117 3.3v not the best replacement but one i had available

some photos


green light and ready to go


Sunday, August 9, 2020

schlieren on a stick


schlieren imaging (wikimit and nasa)

Schlieren photography is similar to the shadowgraph (an optical method 
that reveals non-uniformities in transparent media like air, water, or glass)
and relies on the the fact that light rays are bent whenever they encounter changes

shadowgraph (bullet in flight - wiki)

what you need 
*spherical / parabolic / concave mirror (the biggest, lightest,
cheapest you can get) acrylic?
rigid selfie stick (length depends on the mirror focal length)
cellphone (video mode with led powered on)

*spherical mirror will achieve better uniform results

how to adjust
glue the mirror to the far end of the selfie stick
hang the phone on the selfie stick handle
extract the selfie stick to the point which the reflection of the led
seems to be smallest (about twice the focal length of the mirror) 
and that the led reflection covers the phone camera lens
zoom in, adjust the contrast and enjoy your new toy :-)

photo of the wanted (selfie stick) setup


and a video

some more videos


some notes
selfie stick was too flexible to get solid results
need to find a robust selfie stick (carbon fiber?) and make another video
auto exposure of the cellphone app drive me nuts need to find
proper video app with fixed exposure 

further reading:

Raffel, M. & Heineck, James & Schairer, Edward & Leopold, Friedrich & Kindler, Kolja. (2012). Background Oriented Schlieren techniques for helicopter related large scale and flight testing. 38th European Rotorcraft Forum 2012, ERF 2012. 2. 1-9. 


https://epjtechniquesandinstrumentation.springeropen.com/articles/10.1140/epjti/s40485-018-0045-1

Friday, May 22, 2020

reverse engineering and enhancing mosquito moth led suction trap


There was the hum of mosquito, a bite and an itch
i had to do something about it..

cheap USB mosquito trap (amazon search)
reasonable price and performance

some teardown photos

a series of LED's and motor powered by 5V / USB

bad resistor replaced by a wire

cant really tell why the dense bar barrier
maybe it helps to keep the insects when powered off
but its just adding pressure against the fan
and anyhow if its off then it doesn't catches flies

two common fan types are
static pressure - designed to push air
and high air flow - designed to move air
both have different properties such as
number of blades and different angle of attack

usually you would use a static pressure fan to push air against heat sink
in order to achieve it the blades need to be closer to each other
so that air couldn't flow back

and high air flow fan to ventilate open space
in order to achieve it the blades needs to be further away from each other
to catch and move more air

small dc motor probably cheaper to manufacture

power consumption suggesting
it can run from a small solar panel or batteries 

multiple LED's 

LED's wavelength - checked with spectrometer

some suction numbers using anemometer

half of the trap covered with a piece of fabric
increase the suction to a possible measurement point 

it actually seems to work better without the white bar barrier
which makes sense knowing how fans work
already possible to lower the BOM parts 
while enhance the trap efficiency by a 100%

and less pressure on the fan
meaning decreases in power consumption

final trap mod

after seeing the possibilities for improving the trap
i thought about building my own DIY version
using items i had in my home

its a 12V version powered by an ac dc transformer 
CPU fan + telescoping air guide


dc dc for driving the LED
or even better a drop down 2W resistor
to generate heat to further attract the mosquitoes

plastic storage box - also good for defusing the light
and the round cover assists the air flow
couple of wooden stick and some hot glue

some suction numbers

further reading
first a note of caution:





Wednesday, May 20, 2020

teardown wavetek meterman sf10 short finder brush








 not much in here just two 555 timers and lm324 op amp

TL555C Description
The TLC555 is a monolithic timing circuit fabricated using the TI LinCMOS™ process. The timer is fully compatible with CMOS, TTL, and MOS logic and operates at frequencies up to 2 MHz. Because of its high input impedance, this device supports smaller timing capacitors than those supported by the NE555 or LM555. As a result, more accurate time delays and oscillations are possible. Power consumption is low across the full range of power-supply voltage. Like the NE555, the TLC555 has a trigger level equal to approximately one-third of the supply voltage and a threshold level equal to approximately two-thirds of the supply voltage. These levels can be altered by use of the control voltage terminal (CONT). When the trigger input (TRIG) falls below the trigger level, the flip-flop is set and the output goes high. If TRIG is above the trigger level and the threshold input (THRES) is above the threshold level, the flip-flop is reset and the output is low. The reset input (RESET) can override all other inputs and can be used to initiate a new timing cycle. If RESET is low, the flipflop is reset and the output is low. Whenever the output is low, a low-impedance path is provided between the discharge terminal (DISCH) and GND. All unused inputs must be tied to an appropriate logic level to prevent false triggering.



LM324M Description
The LM124-N series consists of four independent, high-gain, internally frequency compensated operational amplifiers designed to operate from a single power supply over a wide range of voltages. Operation from split-power supplies is also possible and the low-power supply current drain is independent of the magnitude of the power supply voltage. Application areas include transducer amplifiers, DC gain blocks and all the conventional op amp circuits which now can be more easily implemented in single power supply systems. For example, the LM124-N series can directly operate off of the standard 5-V power supply voltage which is used in digital systems and easily provides the required interface electronics without requiring the additional ±15 V power supplies.

LM324M pulse response

TL555C pulse characteristics


diy version
just used a braided 10 awg non coated wire
and connect it to a multimeter in continuity mode
meters that dont have a dedicated continuity mode will be slower in their response



Thursday, May 14, 2020

teardown wireless serial adapter hps-120

teardown handyware handyport hps-120 serial transceiver
download datasheet link


General Descriptions:
The HPS-120 from HandyWave is a ready-to-use short-range wireless connectivity solution for
industrial. It provides the most economic and powerful way of cable replacement for the serial
communication systems.

1.2. Key Features
 No need of external host and software
 Easy of installation and use
 Supports configuration of the local device
 Supports configuration of the remote device via Over-the-Air
 Easy of maintenance
 Supports up to 100 meter (Line of Sight)
 Supports RS-232
 Supports Point-to-Point and Point-to-Multipoint Topology

1.3. Key Specifications
 Operation Frequency: 2.4GHz ISM Band
 Transmitted Power: Max 20 / Typical 16dBm
 Received Sensitivity: More than –80dBm
 Power Supply: DC +5 ~ +12V
 Current Consumption: Up to 200mA at DC 5V
 Operation Temperature: -20 ~ 70 C
 Dimension (w/o antenna): 35mm (W) x 65mm (D) x 16mm (H)
 Baud Rate: 1.2, 2.4, 4.8, 9.6, 19.2, 38.4, 57.6, and 115.2Kbps
 Antenna Interface: SMA Female
 Signal Interface: D_SUB 9 Pin Female




The SP3222E and SP3232E series are RS-232 transceiver solutions intended for portable or hand-held applications such as notebook or palmtop computers.
The SP3222E / SP3232E series has a highefficiency, charge-pump power supply that requires only 0.1µF capacitors in 3.3V operation.
This charge pump allows the SP3222E / SP3232E series to deliver true RS-232 performance from a single power supply ranging from 3.0V to 5.5V.
The SP3222E / SP3232E are 2-driver / 2-receiver devices.
This series is ideal for portable or hand-held applications such as notebook or palmtop computers.
The ESD tolerance of the SP3222E / SP3232E devices are over ±15kV for both Human Body Model and IEC61000-4-2 Air discharge test methods.
The SP3222E device has a low-power shutdown mode where the devices’ driver outputs and charge pumps are disabled.
During shutdown, the supply current falls to less than 1µA.



BC417143B interfaces to 8Mbit of external Flash memory. 
When used with the CSR Bluetooth software stack, it provides a fully compliant Bluetooth system to v2.0 of the specification for data and voice communications.. 
System Architecture BlueCore4-External has been designed to reduce the number of external components required which ensures production costs are minimised. 
The device incorporates auto-calibration and built in self test (BIST) routines to simplify development, type approval and production test. 
All hardware and device firmware is fully compliant with the Bluetooth v2.0 + EDR specification (all mandatory and optional features). 
To improve the performance of both Bluetooth and 802.11b/g co-located systems a wide range of co-existence features are available including two types of hardware signalling: basic activity signalling and Intel WCS activity and channel signalling

Tuesday, May 12, 2020

fix repair ebay find SG382 SRS rf signal generator and SG385 power supply

SG382 DC-2.025Ghz Stanford Research Systems

symptoms no 10Mhz at the rear output
front panel not responding
photos taken at later date but 
when i opened it for the first time it was covered
with heavy layer of soot black residue 
no scheme but there is the circuit description
which for this case was just enough
some pictures of the boards






the rear 10Mhz was fixed after replacing a faulty resistor 
R101 4.99kohm on the main motherboard
didnt have smd so i used a regular size instead 
but as long as it fixed the problem i was happy with it


the front panel was fixed after a short reflow of the spi ic's (U308, U309)






during the repair process i also accidentally shorted something
on the dc dc power supply SG385 (15V, 5V, 3.3V, -5V, -15V)
after some probing seeing half the expected voltages 
which was strange i traced the problem to LM358
which was shorting it was for the temp control 
also replaced the fan which looked tired