Nixie tube clock. 2016-12-15

I will not write alot regarding the electronics since it's not my design. I saw a collegue build this clock and asked if he had a kit i could buy from him. The clock uses russian tubes called IN14 and they have CCCP printed on the back. Also the clock uses a RTC in case of powerloss which is great.

Using a piece of 25mm oak tree gives a nice finnish together with the protective dome which is actually a dome from a surveillance camera. It's a great looking project and i'm really happy with it. Also a cool thing which is not visible on the pictures is that the dome is treated with som kind of UV treatment. This UV treatment makes the gas in the tubes more visible and the tubes glow in even better in dark.

UsbSafe². 2016-11-16

Making a second attempt on my USB fuse, but this time with SUCCESS!!

Added some requested functions and the fuse features now

1Current limit/monitor mode.

2Over voltage protection. (6.5V)

3Anti Juice jacking mode.

4Higher max input voltage (15V)

5Better pcb layout & design.

Follow the link to CrowdSupply and UsbSafe²

Dave on EEVblog finds a UsbSafe² in the mailbag! 

Producing 100 units of UsbSafe² requires a jig for production flashing. I use the unpopulated pcb for UsbSafe² with drilled hole at every test point. Pogo pins are mounted in the holes to apply connection to the boards to flash. The pogo pins are connected to the flasher thru a 10pin header.

Crowdfunding summary.

The first thought after having a succesfull campaign is that it's really really really hard to have any real economic success. There is alot of expenses that are really hard to predict. There are alot of small amounts of fees that in the end makes the profit become zero in best case.

Production costs will always be higher than predicted. Import taxes has huge impact on profit and can easily be forgotten. Dave on eevblog has a recomendation to at least sell your gadgets 2.5*cogs to cover all expenses. I had around 2.0*cogs and it was not enough. My profit was none. I barely covered production and shipping expenses!

With that said, i did not loose any money and it has been great fun and experience to follow it through. I learned alot and will not fall into the same traps again.

My main lessons from this campaign are

1 It's great fun and i will do it again!

2 If i cannot set a price=2.5*cogs or more, i will not go through with the idea.

Update 2017-03

1st batch of units are ready to be delivered. Itead produced 100pcs. They all look great. Only 4 units didn't work att first. Three had excessive solderpaste which short circuited a transistor. One unit had a faulty transistor that was replaced. Except this they all worked out great.

2016-10-10 Heat Chamber

I needed a heat chamber for testing different designs. Having some time over i built a 20L heat chamber in the easiest way. The box is built with 25mm mdf. Using a really cheap STC-1000 temperature controller gives enough accuracy (+-3 degC).

As heater elements two 250W/230V heaters are connected in series to calm the whole system down and not make the temperature variations to fast. Maximum temperature for the chamber is 70degC and takes about 20min to reach. Also a LED lamp for 12V is installed for better vision.

USB Fuse. 2016-01-15

I often connect wierd stuff to my USB ports on the computer and the risk is that the port is somehow damaged. Off course depending on the PC the USB port is protected in different ways but it feels better to have an external fuse. At the same time i thought it could be good too have this fuse functionality when charging phones, tablets or whatever. With the growing market of endless USB connectivity it's a good ensurance with the external fuse.

There are 5 current thresholds that can be set by pressing a button. This makes the fuse circuit universal and easy to use. Currents that can be set are 500mA (USB1/2),

900mA (USB3), 1.5A (Android charging), 2.1A (Android charging) and 2.4A (Apple charging).

Each set current mode is shown if a short button press is applied. The LED will then blink fast

1-5 depending on current mode. Otherwise the LED blink every 3rd sec.

When a short circuit/ overload is detected the +5V output is disabled and the LED is turned on, the fuse is kept in this state until the button is pressed. At insertion of the fuse to a port it always shows once what current mode is set.

Maximum voltage drop across the whole fuse is around 240mV@2.4A