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Archive for the ‘ebay’ Category

Mass production is a wonderful thing. Prices fall, and hobby hackers get cheap gear. The mind then wanders towards what can be done with it. So it’s little wonder that someone like [Aaron Christophel] would try to repurpose those sub-$3 AVR programmers that are all over eBay (translated poorly out of German here, but demonstrated in the video embedded below).

[Aaron] didn’t have to do much, really. The only trick is that you’ll first need to re-flash the existing ISP firmware with one that lets you upload code to the device itself over USB. If you don’t have an Arduino on hand to re-flash, buy at least two of the cheap programmers — one to program the other ones. Once you’ve done that, you have essentially an Arduino with limited pinout and two onboard LEDs, but in a nice small form-factor and with built-in USB. [Aaron] even provides an Arduino boards.txt file to make it all work smoothly within the IDE.

All of this is done with the very friendly V-USB firmware, which lets you build up low-speed USB devices on the cheap and easy. This would be perfect for making a couple-key keyboard, a USB-USART or USB-SPI bridge, or even a volume control knob — one ADC pin seems to be broken out. With some delicate soldering, the rest of the pins could be brought out and you could do something really useful with this little dongle.

It’s hard to imagine even sourcing all of the parts for the cost of having one of these shipped to your door, and this is a fairly old hack, dating from 2013. We’re a little surprised that we haven’t seen more projects with people repurposing these cheap ISP programmers. Have you made anything with one of these? Let us know.

Filed under: Arduino Hacks

Don’t buy a cheap plugpack…

ebay, education, learning electronics, plugpack, repair, voltage converter, wall wart Commenti disabilitati su Don’t buy a cheap plugpack… 

Hello readers

Now and again in the quest to save money, or to buy something that you need when you are short on cash, you inevitably end up trawling through eBay for what you need. Last month I needed some 20V DC 1 amp plugpacks to test my bbboost prototypes with, so naturally after scoping out retail prices eBay found itself on my web browser. Considering a local alternative costs $38, it was worth a shot. As these were for ‘internal use only’, that is for myself and nobody else, it is ok for me to buy the cheaper option. Well it used to be.

These suckers were found for $5.20 delivered from Taiwan…

No C-Tick or electrical authority approvals on this plug pack…

The first problem was the plug – these were advertised as having Australian plugs, however it was the US-style with adaptor. Naturally the adaptor didn’t fit, and I had to disassemble and rearrange the contacts inside for it to accept the flat pins. Second problem was the heat – this little monkey would run hot, even without a load. I asked it for around half an ampere and it really cooked. Ouch!

In the words of Dave Jones – “it’s a piece of sh*t!”

So what else was there to do? Wait for it to cool down, and pull it apart!

Wow – what a mess. Even through the electrolytic capacitors looked normal, there was a layer of brown, rusty goop all over the back of the 2n60C MOSFET. Where did that come from? The mind boggles. Everything else looked normal, the PCB was soldered nicely and the capacitors weren’t bulging or leaking. There were holes for a 1k0 resistor and an LED, but they were unused. What else to do? I cut the DC lead from the housing and soldered a 9v PP3 battery snap on the end – perfect for using an Arduino away from the desk for prototype testing…

So the exercise was a not a total waste… the DC plug is worth $2 locally, and the wire was probably worth about fifty cents. The plastic housing might be useful later on.

From now on I think it will pay to fork out for an approved, locally-sourced adaptor. No more eBay! So remember, quality is remembered long after price is forgotten.

High resolution photos are available on flickr.

As always, thank you for reading and I look forward to your comments and so on. Please subscribe using one of the methods at the top-right of this web page to receive updates on new posts!

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