A few weeks ago I was looking around for some components for my various Raspberry Pi projects and I stumbled on to ebay. I have bought and sold things on ebay several times in the past, but always mainly thought of it as a kind of giant flea market – a place to buy and sell unwanted items. I guessed I missed the news that ebay has turned into an international factory outlet. If you look for things related to Raspberry Pi, Adruino, or electronic components in general, you quickly find lots of vendors selling direct from China. The prices are incredible. Whole, fully-populated, circuit boards shipped round the world for less than what it would cost just for the postage in this country.
I was so intrigued that I thought I’d give it a try, so I ordered a selection of interesting and/or useful items.
A packet of stuff arrived today and I eagerly opened it. Mostly it was just as I expected (although there is one board which I vaguely remember ordering, but can’t immediately recall what for…) The only problem was with the packing. Among other things I had ordered some relay boards – one with two relays and one with four. The four-relay board arrived largely unscathed, but the two-relay board had obviously bumped into something else in transit which had severely bent the control header pins.
I can’t be bothered to try and return this item which only cost about £1.50, so this means if I want to use it I will need to repair it. My first attempt will be to try and straighten the pins by gently adjusting them with a pair of piers. It seems quite likely that at least one of the pins will break during this process. If it does, my plan B is to de-solder the pins and replace them, either with some of my stock of generic header strip, or by simply soldering flying leads to the board. Which one I choose depends on what I decide to do with the relay board!
I do this too! And I can confidently say you’re not the first person to receive a piece of electronics in the post and wonder what the hell it is! (*ahem*) One wonders if a bit of labelling would kill some of these sellers :p
It is so tempting to buy these things because they just seem so cheap for what they are. I have now identified the mystery board. It’s a AD9850 DDS Signal Generator Module 0-40MHz. It looks really interesting, and potentially useful if I am going to be playing with building and testing analogue filters and amplifiers for my ultrasonic project.
Another down-side with buying things this way, though is that it comes with no instructions or usage examples. A bit of googling has thrown up a datasheet for the AD9850 chip, but it’s pretty light on how I might actually control it from a Raspberry Pi, and Arduino or whatever. Still I guess that’s another blog article in the making.
I’ve bought a few duplicate boards in the hope that once I’ve set them up and used them on the RPi I can then sell the duplicates on eBay for those people who don’t like Chinese sellers. Not actually done it yet, mind you!
I’ve recently had the same problem with bent header pins on one of two I2C LCD interface boards ( @£1.50 each with postage ).
Bear in mind that Ebay vendors heavily rely on having a good reputation to continue trading. Check out their % positive ratings feedback.
They are usually desperate to keep those ratings high – so they take any negative feedback very seriously. This tends to make them very responsive to their customer complaints. They would rather pre-empt bad customer feedback as many people check their ratings before trusting a purchase. It only takes a second to email them (Look at >My Ebay>Purchases>Contact seller).
Prolly not worth asking for a refund (but what’s the harm?) but worth remembering for other more valuable items or asking for a future discount.
Anyways, let us know how you get on with those relays if you intend to use I2C ‘cos I have a plans to use several of those (via the Slice of Pi/O).