ALIWAL NORTH SAR LAYOUT: Small Projects

Thursday, December 10, 2020

Reinforced the steerer tube and a simultaneous upgrade of the steerer / stem of our Bikejoring bicycle: (From threaded to semi threaded)

BEFORE UPGRADE - quill type stem.

The bent steerer tube.

The straightened steerer tube.

Reinforced steerer tube.

Project engineering drawing.

One of the precision machined teflon bushings
used in this project - 25.4mm inside diameter
and 31.8mm outside diameter.

The different parts.

AFTER THE UPGRADE - the outcome.

Ordinary tools were used...

My new torque drive.

Saturday, April 13, 2019

Been busy lately, planning and building a new "car bike rack" for our Bikejoring bicycle...

Friday, February 02, 2018

An "ATN X-Sight II HD" on the workbench today for a new battery pack / power supply modification.

ATN X-Sight II HD

Disassembled

Loose tags on the mini USB socket

Almost impossible to solder those loose tags on the mini USB socket... The plan is to assemble a 3 volt regulated power supply, powerful enough to power this power hungry rifle scope. The 9 Watt power supply (DC to DC converter) must be robust to withstand vibration, must be mounted externally on the rifle chair, the input of this unit to be connected to a 12 volt battery and the output via a USB cord which is pluggable externally on the scope and internally soldered to the existing DC power battery housing. The battery housing must still be able to be loaded with batteries when the hunter is on foot and away from his vehicle...No obvious holes to be drilled through the shell of this scope, need to utilise any available existing hole... ROME WAS NOT BUILT IN ONE DAY!

The battery box

Had to drill a 3mm hole

The prepared USB cable is now on the
inside of that already very full chamber

The disassembled battery box

Cable soldered and the scope
assembled to its original state

The USB socket is secured to
the side of the scope casing

Getting heat out of a sealed
power supply enclosure:

In harsh environments where a sealed
enclosure is necessary, baseplate cooling
is a simple, but not so inexpensive solution
to thermal management of power supplies.

A new approach using discrete components
can make baseplate cooled power supplies
smaller, more efficient and more flexible.

A baseplate cooled power supply has

most of its heat generating components,

such as the switching FETs, diodes,

regulator ICs and magnetics,

mounted in direct contact with

the metal baseplate so that heat can

be extracted using thermal conduction.

The assembling and testing phase:

The 12 Volt DC input side.

The 3 volt DC output side.

Typically the power supply is bolted to the
inside of the sealed box, so that the metal
box itself can act as a heat sink, or heat
can be transferred from the box to an
additional externally mounted heat sink.
It’s wise to check whether the box can act
as a large enough heat sink to conduct the
heat out of the unit, or whether an additional
external heat sink should be added, because
getting this wrong will have a significant
impact on the reliability of the power supply.

Power in = 8.46 Watt (12.44 V @ 0.68A)

Power out = 2.05Watt (3.06 V @ 0.67A)

8.46 Watt - 2.05Watt = 6.41 Watt is

therefore dissipated (wasted) as heat.

Measured the baseplate temperature at
39°C at an ambient temperature of 27°C.

The finished product:
Made and fitted both aluminium end cover plates.

Wednesday, January 31, 2018

Made provision for the unexpected long utility power outage.

Change over switch (Kraus & Naimer)
with instructions and Generator to
Home hook-up cable

Onyx waterproof generator inlet

Standard Main DB Wiring Diagram.

Main DB Wiring Diagram with
Generator to Home hook-up

Assembled this Mains Monitor circuit;
To be mounted next to the change
over switch, in the store room.
The Power Supply in the blue durable
plastic enclosure will monitor the
restoration of the Mains after a mains
outage, while the generator supply is on,
and relays a signal to the little
white box, mounted in the kitchen.
The white box contains an LED for a
visual indication and a 12 Volt buzzer
for an audible indication.

Mecer 1200VA, 720W, 12V DC-AC Inverter
with LCD Display and Socket for Optional
Solar Power Module, with sufficient
deep cycle battery backup to power
sophisticated electronic equipment
during a mains outage.

Mecer 1200VA, 720W, 12V DC-AC Inverter
with LCD Display

Battery connections through an Isolator Switch

Load shedding survival tips

Plan your activities and travel around anticipated load shedding.
Be creative with dinners and activities to keep yourself and your family entertained.
Have braais (BBQ's) and set up a tent for the kids with a campfire, especially during this holiday period.
Invest in rechargeable emergency LED lights. They are bright enough to light up the room for homework and household activities.
One can also buy an inexpensive two-burner gas stove at any major retailer and cook using gas.
Load shedding affects the ability of the water utility to pump water, so make sure you have water stored in the house.
It also means no fibre to the home, so make sure your phone has data or airtime.

Carry cash, as some retailers are unable to take card payments.

Wednesday, April 19, 2017

How I utilized available dead space - transformed an existing niche / window recess to serve as a display cabinet for my 1/87 scale model vehicles and some other models.

Plexiglas® shelving is in place,
test fitting the wooden frame.
Then to fit the glazing in
the door frame and then
the LED strip lights.

Glazing is done and the
shelves stocked with models.
To install the LED strip lights.

Finished with the first cabinet:

With LED strip lights installed
on the inside and on both
sides of the door frame.

Finished with both cabinets:

Wednesday, January 11, 2017

Experimenting with a "new" peeling paint technique, unfortunately this would work for larger scale modelling, not for my HO scale, but on the other hand, nothing is gonna stop me from trying.

(The wood sample is 60 mm x 9 mm)

Mineral Turpentine base coat,
followed by a coat of acrylic
matte craft paint. Waited till
dry, then scraped with a
fine hacksaw blade.

Tuesday, November 08, 2016

A small 12 VDC to 5 VDC 1 A, +ve regulator / converter (4,5 cm x 4,5 cm x 2,5 cm)

25 volt rated electrolytic
capacitors were used for
this project.

Saturday, October 15, 2016

Uncoupling of Model Train rolling stock fitted with Kadee Magne-Matic couplers - using two stationary round bar magnets in this scenario.
Perfect for shunting / marshalling yards...
It is a matter of trial and error in the placement of the round bar magnets. Lots of patience needed during this exercise.

Friday, May 20, 2016

"I hear and I forget. I see and I remember. I do and I understand"

Confusing - Spot the difference between testing with an Analogue and a Digital meter.

Analogue AVO meter diode test:
Set the meter to measure ohm x1 scale.
This method of diode testing, using an analogue meter is able to detect whether a diode is operational or not. However, it cannot provide any parameters about the performance of the diode! This is not normally a problem because the performance of the diodes is normally tested or guaranteed by the manufacturer.
Most failures of diodes are catastrophic, rendering the diode completely non-functional. This simple analogue meter test is able to detect whether the basic diode function of the component is intact.
The test basically relies on using the meter to test for the resistance of the diode in both directions. In the REVERSE direction, the diode should NOT conduct and will indicate a VERY HIGH resistance, whereas in the FORWARD direction, it WILL conduct and indicate a LOWER resistance.
IMPORTANT: When testing a diode with an Analogue Meter in this way, it should be remembered that the terminal used as positive terminal for measuring voltage, etc., is actually negative with respect to negative terminal. In other words the polarity on these terminals appears to be the opposite of what might be expected (ONLY TRUE FOR ANALOGUE METERS WHEN SET TO THE RESISTANCE READING !!!) This is because of the way the analogue meter works and it is not the case when testing with a Digital Multimeter!!
As a result the readings for testing a diode with an AVO analogue meter versus a Fluke digital multimeter in this way are as given in the diagram. Spot the difference!!

Testing of Diodes and Transistors out of the circuit is only possible by testing with an Analogue AVO meter or a Digital Multimeter set to Resistance Measurement in Ohm - Capacitors can only be tested with an Analogue AVO meter set to Resistance Measurement in Ohm, which is why I cherish my AVO meter.

Saturday, April 23, 2016

Found this in the archives... A very handy Simple Transistor Tester.

Wednesday, April 06, 2016

AC MAINS POWER TRIMMING:
I made use of MOVs (Metal Oxide Varistors) and fast blow fuses to protect my electronic appliances at home against high transient voltages and power surges.
A fuse is simply NOT ENOUGH!
(A metal oxide varistor (MOV) / voltage dependent resistor (VDR) is a component which has voltage - current characteristics that is very much similar to that of a diode.)
This component is used to protect electrical devices from high transient voltages.
MOVs are bonded together to an electrical earth.
They are planted in the devices in such a manner that it will short itself when a high current is produced due to the high incoming mains voltage/surge.
The inline fuse will blow cutting off the supply, thus the current dependent components in the device will remain safe from the sudden surge in excess of 290 Volt.
(You need this in Africa)

Friday, July 31, 2015

TIPS of the trade. I use ordinary kitchen Goldilocks brass scrubber (brass sponge) for continuous cleaning of my Soldering Iron tip - one piece of Goldilocks in a very small tin next to my Solder Station does wonders.

Making a Resin Core Solder Feeder

Coil up some resin core solder on
a pencil, with the one end fed
through the centre of this coil.

Stick this coil inside a redundant
silicone nozzle as displayed
in this image.

Close the big open end of the
silicone nozzle with some other
miscellaneous plastic cap, you
now have a neat and handy
pencil type resin core solder
feeder to make any soldering
job a feast.

Hands free soldering - homemade simple PCB holder clamp, helping hand, very effective though...

I used an ordinary Badge Clip
for this project.

I have lined the jaws of the Badge
Clip with a very thin rubber strip
to improve the grip and attached
it to a piece of recycled flat bar.
Clamped this gadget in my small
bench vice.

The unfinished PME printed circuit

board is firmly gripped.

The finished PME printed circuit
board is firmly gripped.

Keep a 3 Volt Lithium Cell handy on the work bench for testing of LEDs. The LED leads make easy contact with the lithium cell terminals.

Thursday, May 29, 2014

My homemade, Nicad battery powered Static Grass Applicator can hold almost 1 cubic decimetre of static grass in the canister.

1. You need this to begin with. IonB2 from - http://secure.oatleyelectronics.com/product_info.php... - Two domestic plastic canisters with lids, metal gauze, 12 volt switch with LED indicator, one mono miniature Mic socket and jack, 12 volt Nicad batt pack, crocodile clip and some stranded flex copper wire etc.

2. You will find these items from RS Components (online store) -

http://uk.rs-online.com/web/c/batteries/rechargeable-batteries/speciality-size-rechargeable-battery-packs/

3. How to make your own Static Grass Applicator (Body) - Model Railroad. Please watch both video clips, Parts 1 and 2 - https://www.youtube.com/watch?v=8gYmeRaaaL8

Required Electronic skills level - intermediate to advanced.

Static grass sample - waiting for PVA glue to dry
(about 2 to 3 hours in warm weather), then peel
off slowly from the tin lid with a sharp blade,
and stick it to the layout with PVA glue.

Made these tiny grass tufts this morning.

Static Grass Tufts glued to Aliwal North SAR Layout.
Painted grass tips with Lemon Yellow acrylic paint.

Tuesday, January 28, 2014

Another very tiny printed circuit board for HO and N scale model SAR 19D Locomotive constant DC directional lighting

LINK: A 6 diode constant directional lighting circuit. (Courtesy Mark L. Rollins)

Tuesday, December 17, 2013

Flashing Orange LED - Orange Beacon Light for an HO Scale SATS Trolley: 555 timer IC - LED flash timing is adjustable - 9 volt battery supply.

Overview
This circuit uses the 555 timer in an Astable operating mode which generates a continuous output via Pin 3 in the form of a square wave. This turns the LED (D1) on and off. The speed at which the LED (D1) is turned on and off is set by the values of R1 and R2.

Parts List
1x - NE555 Bipolar Timer
1x - LED (Red)
1x - 470K Resistor (1/4W) ( I have replaced the 470K resistor with a 1 MOhm Potentiometer)
2x - 1K Resistor (1/4W)
1x – 1µF Electrolytic Capacitor (16V)
1x - 9V Voltage Battery

Schematic

Fixed Flashing Mode