The Inside of a Solid State Relay from Ebay

Hi all! Sorry I haven’t posted in months, I’ve been really busy with various things!

I ordered a solid state relay off of Ebay for my project, which I’ll post on here when it’s done. It worked fine for a couple of days, but eventually, it failed in the open position. I used plenty of thermal paste, a large heat sink, and all I was driving was some christmas lights, so I was sure it wasn’t me. Either way, I contacted the seller and they sent me a new one for free.

Opening the dead relay was harder than I expected. In the end, I had to chip away at the plastic until it came off. It took about half an hour in total.

I couldn’t get it apart any more than I did, because the whole thing is covered in a weird solidified goop.

It doesn’t look as unsafe as some people say about Ebay relays. The low voltage side and high voltage side are far apart. The high voltage side has traces that definitely can support 25 amps, which is what the relay is rated for.

I tried to get the triac off to see if it had thermal paste behind it, and to see if it had anything visibly wrong with it, but the gunk was in the screw and I couldn’t get it out, unfortunately.

Pictures of the inside below.

The bottom of the PCB. The right is the load/high voltage side. The left is the input/low voltage side. See the lines in the solder on the right? That’s where 2 of the triac terminals went, far from each other and far from the low voltage side.
The top of the board, covered in solidified goop. Left is low voltage, right is high voltage.
The bottom of the relay. The triac is mounted on it. It’s made out of metal, but it’s hard to tell with all the goop on it.

I tried to make a custom PCB today…

It didn’t work.

First, I designed my board in Eagle. The board was to connect my servos to my Arduino, plus some other accessories. It was going to be for my robot Dalek.

Next, I printed the board onto clear paper. I purchased the paper off of Ebay, and it said it was compatible with both Inkjets and Laser-jets. I think this is where I went wrong: My inkjet is too low quality to print PCBs. I am going to try using my dad’s laser-jet sometime.

I put the clear paper against my PCB, and put a 15 watt fluorescent light about 2 inches above it. I left it there for about 15 minutes.

Once it was done, I mixed some MG Chemicals 418 with water, 1:10. I put the board in, and at first, I saw the outline of my board! But as I washed the board, it faded. This is what I’m left with.

2014-07-03 14.28.26 2014-07-03 14.28.40

It’s hard to see in the picture, but there is a tiny trace of my schematic. Can’t wait to try again with the laser-jet!


Project Ideas

Hi guys,

This is a list of project ideas I’d like to do sometime, more for me than for you.

Weather Station:

  • Located at backyard lake
  • Waterproof security cameras
  • Communicates via wireless to house
  • Records rainfall, lake temperature, lake salinity, barometric pressure, temperature, wind speed
  • Small internal hard drive in case of server outage
  • Backup batteries
  • Motion detector and alarm inside
  • Solar powered
  • Antenna at home to communicate with NOAA satellite
  • Powers off less vital equipment as power starts to drop, security system last

Weather Balloon:

  • Takes many different readings
  • Sends live to base station in case of data failure
  • NTX2 transmitter
  • Beaglebone Black


More will be added in the future! Thanks for reading!


Product Review: LTSP

Here’s my review of LTSP, or Linux Terminal Server Project. Please keep in mind I am not a professional journalist!

Installation was extremely easy. I found the documentation easy to follow, and I had no problems setting it up. All it was a few commands, a bit of waiting, and viola! An LTSP server!

I connected a thin client, and found it would not boot. I had to configure dhcpd! I went back on to LTSP’s website, and sure enough, they had documentation for that, too! Within minutes, I was able to successfully boot my first thin client!

Too good to be true? Sort of…

I found it to be very laggy, definitely a problem. After about 15 minutes of googling, I find out that the server and client are communicating in an SSH tunnel, the way it is supposed to. It has a fatal side effect: more lag. Seeing as this was only for home use, and I don’t think my friends have any plans to sniff my thin client traffic, I turned off the SSH tunnel. Immediately, I found an improvement! Before, I could barely do word processing, now I can even play some games!

I found the documentation to be a bit lacking in some areas. I have questions that I couldn’t find the answers to. “Will installing a better graphics card in my server improve game performance?” is my most important one.

So, where am I now? I have a server set up with a single client. Yes, I know it’s not worth it at that small scale, but I have plans to install more thin clients later. I have changed the login screen – I used a Doctor Who background coupled with a ‘Please login below’ image. I even changed the colour of the login text!

My father uses the thin client every day, and the only complaints I have had are because of me(Unplugged network cable, server stopped due to power outage, etc.) other than that, he is very happy with it!

Overall, I rate LTSP 9/10, and here’s why:

  • Installation and configuration was easy
  • No severe problems
  • Almost everything is configurable
  • I wasn’t able to have it connect to an RDP server, even when I follow their instructions
  • Documentation not provided in some areas

That’s all, hope to post more soon