Oscilloscope

Once you are building electronics projects, the ability to take a look at what is going on in the real world is invaluable for troubleshooting. For this you really need an oscilloscope which are usually quite expensive. I found this kit that gives a low cost way of entering the world of electronics instrumentation.

oscilloscopekit

I bought the version with the surface mount chips presoldered as they are tiny and I was careful to sort the components before starting.

oscilloscopechip

I used my component tester to make sure that I was using the right components. Here it is working connected to the test signal.

oscilloscope1 (3)

You can power it from a small 9V battery making it very portable. While it only works up to 200kHz and the screen in tiny at 2.4 inches, that is plenty good enough for most projects and you can’t beat being able to see what is happening when you are building a project or writing some software that interacts with the real world.

Roast Chickpeas

If you are looking for a healthy alternative to crisps (chips) roasted chickpeas make a nice snack.

Drain some cans of chickpeas and pat them dry (pictured are 2 cans worth). Put them on an oven tray on some parchment (baking) paper) and add 1 table spoonful of oil and flavour to taste. Here you can see from left to right:

  • cayenne pepper
  • garlic
  • curry powder

roastchickpeas1

Heat at 450F (230C) for about 40 minutes… take care near the end of the cooking as they finish roasting quite quickly… check at 35 minutes and keep an eye on them until they are done.

roastchickpeas2

Yummy!

 

 

 

 

Component Tester

When doing electronic projects, its critical to put in the right components. I found this fantastic component tester that solves that problem economically.

componenttester1 (2)

It can test Transistors, Diodes, LEDs, resistors, capacitors and Inductors.

Here are a few more modes.

 

The unit automatically detects the type of device under test. See how for the LED the forward voltage has been tested.

I purchased it from here: Banggood Component Tester

You can get kits and a few variations on the basic theme. I purchased a ready made one as the point was to be able to test components for building other kits. So far its been $22 well spent as I was able to avoid making mistakes when reading tiny 5 band resistor colour codes  like these that I had to use an eye loupe to read. In this case the red and brown were so close in colour I really needed the tester to be sure. Its much easier than a multi-meter. It has 3 ports for transistors. The only slight flaw i can see is sometime with an open port it thinks there might be a very large resistor present, but it still measures the device under test correctly. Also it does not measure under 30pF capacitors.

resistors1

I did some research and found these original sources that contain the schematics and code and theory of operation.

Markus Frejek

Karl-Heinz Kübbeler

Karl-Heinz Kübbeler continued

 

 

More Dehydration

We’ve really enjoyed the dehydrated food we have made, but the oven is not that energy efficient and you have to keep an eye on it…. we don’t like leaving the oven running overnight and the temperature is a bit tricky to keep constant at the low levels needed for dehydration. So we’ve taken the step of buying a real dehydrator.

We looked at a lot of reviews with the following criteria; works well at the primary job of dehydrating; can dehydrator a large quantity; not too much counter space taken up; inbuilt fan, temperature control and timer; a reasonable price; and we came up with the following unit which so far has really impressed us. Here it is at the manufacturer’s site.  Klarstein Dehydrator

dehydrator1

 

The unit takes 6 trays in a stack. You can adjust them for 2 thicknesses of food easily just by rotating them, and it comes with a fine mesh insert for small foods like berries. It has a timer and temperature control. The heater is at the bottom and there is a fan for circulating the air.

Here it is in action with some fruit. As you can see we are using 3 of the 6 possible trays which is another advantage of this design. Its also rectangular which is efficient on the counter space and for storage, whereas there were several round ones we looked at that were less easy to store.

dehydrator4 dehydrator3

So far it seems great. You can adjust the order of the trays easy to compensate for different speeds of drying and the timer and temperature control mean we can set it running overnight.

 

Replacing a Zipper pull

I’m a fan of trying to repair stuff as it can really prolong the value. Too often in this day and age people throw out perfectly good stuff that can be fixed with a little bit of patience. The zipper on one of my favorite fleeces failed and I could not do it up or remove it… a repair was pretty simple and a fraction of the price of  taking it in to be fixed. This fleece has a plastic zipper so I could not remove teeth to get the slider off (with metal teeth you can replace the slider by removing a tooth and then re-attaching it). As you can see the pull had worn through and it kept coming off the slider.

zipper1

First I removed the broken part. Then I made a replacement from 1.5mm copper wire (16-14AWG). I formed this into a rectangular shape with an overlap using needle nose pliers.

zipper2

Then put this through the hole in the slider and closed the loop. (oops forgot to take a picture before I soldered it). I own a soldering iron so I joined the wire with solder (being careful to keep the heat from the zipper and fleece by using the pliers as a heatsink), but epoxy glue will work just as well. File the ends to keep them smooth so they don’t snag.

zipper3

and now it works just like new.

zipper4

You can do the same with a paper clip (although copper will wear well as it is ductile and was easy to join)

Dehydrating Fruit

As we like backpacking, we have started experimenting with dehydrating food to keep weight down. While you can buy special dehydrated meals, they are expensive and we’ve found its pretty easy to do it yourself.

Here is our process for dehydrating fruit. You can do this with canned or fresh fruit. If the fruit is canned you need to drain the juices.

fruitdehydration1

Here we have a mix of fresh apples, and canned peaches, pears and pineapples (We’ll report on the mandarins pictured in a future post). You need airflow to dehydrate the fruit so we have put them on an oven rack above a tray lined with some parchment (baking) paper to catch any drips. Note: do not use wax paper… it will catch fire.

fruitdehydration2

We can dehydrate them in the oven (electric). To do that we put it on a low temperature and use a oven thermometer to monitor the temperature. You want a max of about 70C as above that temperature the fruit cooks. We prop the door open a bit using the handle of a wooden spoon to allow for air to circulate.

fruitdehydration3

After 6 to 12 hours depending on the moisture levels you have delicious fruit strips.

fruitdehydration4

Here you can see that I got the temperature a little bit high as the pineapple has browned a bit. You don’t need any sugar or oils to do this. You end up with incredibly concentrated fruit strips. Remember to drink water with them when you eat them as they have very little moisture inside. If you do a good job the fruit will last for months if you seal them (they reabsorb moisture from the air) … although they are so tasty we eat them pretty quick. The fruit is fantastic in home made granola as it really adds a bit of zing to the flavour.

Zombie Candles

If you are like us and you live in a northern clime, you may like the brightness of candles. We typically burn them in our fireplace as it a great safe place for it.

candlesburning

And of course you end up with lots of left over wax.

Well its pretty simple to generate an everlasting supply. We call them Zombie candles as we can take some larger Ikea candles and get at least 3 or 4 lives from each one. We light them in a handy ceramic tray that we also purchased at Ikea and when they burn down we recover the wax.

candles1

To melt them we use a steel pot in a pan of water that we heat on the electric stove… that way you don’t run a risk of fire. Keep the pan below boiling temperature … paraffin wax melting point is less than 70C.

candles1acandles2candles1b

For moulds, you can purchase fancy ones, but we just use the typical cardboard milk and juice cartons that have a waxy layer inside so they release easily.

candles3

For the wicks you need cotton twine.. you can buy it made for wicks with a loose weave very cheaply … I’ll stress that you need to use cotton… don’t use any type of plastic string as it will burn. We’ve tried a few methods for keeping the wicks straight… you can tie it to a washer (that you will recover when you remelt the next time)… or pre-dip it in the hot wax you are melting. Hang the wick from a wood skewer.

candles3a

Once the wax is melted, the old wicks and any washers tend to sink to the bottom… so you can now take the pot with oven gloves and pour the wax carefully into the moulds.

candles4

Let the candles cools for 24 hours and you have a reborn candle.

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If you want to inject more colour, you can use cheap kids wax crayons added to the mix. We think this is a great way to enjoy candles and be economical about it without throwing away the usual wax meltings.

As always.. be safe with candles. Never leave burning candles unattended or use them near flammable items, children or pets. We use a butane lighter to light them and a snubber to put them out.

N-Gauge Loco Pictures

Thought that I would try some pictures with and without macro. Both taken with an iPhone6.

The subject is a Fleischman 1/160 scale n-gauge model train.

n-gauge loco
n-gauge loco
n-gauge loco closeup
n-gauge loco closeup

Lighting is a pair of LED household lights from Ikea and some reflective foil surrounding the subject. The iPhone is not using flash and not in HDR mode. The second picture uses a clip on macro lens on the iPhone to look at the front driving mechanism. Time for me to clean the track I think as you can see tiny pieces of lint that the wheels have picked up. These were taken freehand… they would probably be better if I clamped the phone. Still I am pretty happy with what can be achieved with not much prep on a phone camera.

Cows and Runes

We tried a new area to hike recently and were surprised at this gem in the Stockholm suburbs. The area is called Järvafältets naturreservat and it is near the Akalla T-bana line. The area is quite large and its pretty easy to go for a more than 20km walk. Its made up of a mix of farmland, small lakes, woodland and small hills.

There are a lot of paths so easy to get a bit disorientated, but they do have a great map that you can pick up at entrances. The paths are not as well marked as the more isolated areas like the Sörmlandsleden, but you are never far from the city. It’s always a good idea to take some navigation device so you can orientate yourself even when close to the city  (eg. smartphone with maps and data connection, compass, GPS).

Jarvafaltet Map
Jarvafaltet Map

At the entrance near Akalla we saw this rune… there are many more in the park but we were pretty unsuccessful in finding them, even with the map and a lot of hunting. We assumed that mostly they are not as spectacular as this one and a bit hidden off the path.

Rune
Rune

jarvafalet rune map

And here is a spectacular cow we saw in a field.

Cow in Jarvafaltet
Cow in Jarvafaltet

and some of the landscape.

trees in jarvafaltet
trees in jarvafaltet
sabysjon
sabysjon