Mailbag_09aug2020

 Some days ago i received some interesting items from Aliexpress / China. Time for another mailbag blog post!

UV detection card

I did see this item in a YouTube video. It is a cheap card an can be used to detect UV light. I did not yet test it, however it seems useful to have for my experiments with UV leds and lamps and other experiments with optics, The mall picture show the backside of this card.

Digital test pen

On Aliexpress i found this cheap digital signal test-pen to test 5 and 3 volt digital signals.  I hope to post soon on my blog some hacks/little improvements.

Pen with conductive ink

In several articles and YouTube videos people experiments with electrical conductive ink are presented.
It looks that you can easy draw your electronic circuit on paper and glue with conductive glue your components. I found this conductive ink on Aliexpress and decided to give it a try.

I did not yet full tested the product. Perhaps i did buy a to cheap conductive ink pen as it was more difficult than expected. Before the ink started flowing i had to shake the pen and to move the pen over the paper several times. When shaping the pen you hear a little ball (?) moving in the ink reservoir.

After trying to write suddenly ink starts to come out of the pen. With my multi-meter i measured the resistance and it was not conductive. To get a conductive line i had to write the same line several times and dry the ink with my heater that i normally use for heat-shrink tube. (First I did not yet use it for real electronic experiments.

Lamp holder

This are cheap lamp holders for GU10 lamps. I ordered some as i want to replace some halogen lamps with GU10 led lamps. At the local hardware stores (Praxis or Gamma) i could not find lamp withe the same diameter as the current halogen lamps.

Temperature sensors

These three legged items perhaps look as transistor. However they are cheap smart temperature sensors (DS18B20 ) .Two wires are for the plus (+) and minus (-) and one wire is used for data transmission to a micro-controller.  Several of these sensors can be placed in parallel and the temperature of each sensor can be read individual as all sensor have an unique address.

Hand drill

This little tool is something i should have bought sooner. In the few days i have it now i used it several times. It has a little drill chuck for little drills. This way i can easy make little holes e.g. in plastic and do not need to use a fast rotating electrical dill or Dremel or punch a holes with other tools.