Random Projects

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In this post I will document some of my smaller projects that don’t deserve a whole blog post of their own.

Radio Transmitter

Years ago I made this FM radio transmitter. It’s powered by a 9V battery and transmits the audio signal from the 3.5mm audio jack. The frequency is somewhere in the range a regular FM radio can receive.

DIY Mini FPV Camera

I made this DIY mini FPV camera for my racing quadcopter back in the day. Nowadays you can buy these small compact camera/transmitter combos already prebuilt for very cheap so it doesn’t make much sense to make your own.

It’s meant to be powered from the 5V output of the flight controller. The dip switches are used to set the channel of the transmitter. As you can see in the right image the camera produces a nice image. The only problem is that it tends to heat up quite a bit which is why I added a little heatsink at the bottom. However, this isn’t a problem as long as you are flying and there is a constant airflow camera/transmitter.

3D Printed Keycap

When I first got my DLP 3D printer I made a couple of test prints including this Pikachu keycap. I decided to paint the key cap, make a little enclosure for the mechanical keyboard switch, and use a 555 timer to turn on the backlight of the switch for some time. This was a kind of pointless project that I made just for fun.

The circuit is made from a 555 timer in the monostable mode that is powered by 5V from a USB connector.

Controlling a Pneumatic Piston With Arduino

This is a simple Arduino pneumatics controller I made as a test before using it as part of my spot welder project. The Idea here is to use a piston on a spot welder to close its the contacts together on the welding piece, weld the piece and release the contacts again.

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These were some of the smaller projects I made. I probably make some additions to this post in the future …

(update) Here is some stuff I added after I initially published this post:

Ionizer

I recently found an ionizer module(that I ripped out of an old hair dryer many years ago) in my parts box. I decided I would make a simple little ionizer by sticking the module into a case of an old broken access point I also had in my parts bin.

Here and here are some interseting videos on ionizers by bigclivedotcom.

DIY Networking Cabinet/Rack

I took the case of my old broken Solidoodle 4 3D printer and converted it into a networking equipment cabinet or “rack” if you can call it that. The switch and GPON modem are stuck to the metal case with a couple of neodymium magnets I took out of some old hard drives. The ISP router sits on the top shelf and the NAS and UPS are on the bottom.

The switch was originally sized for a regular 450mm rack. This was too big to fit into my DIY cabinet so I just took an angle grinder and cut off the sides of the switch to match the width of the PCB inside it(most of the case was just empty space). I also cut out a few slits for the intake and an exhaust hole for a standard 120mm PC fan. Now with the fan turned on everything in the cabinet runs cooler much cooler.

It’s not the most impressive home lab setup, but it’s better than it was before, just stacked up on a shelf. In the future, I really should get a proper rack, with a custom-built server, better switch, patch panel, bigger UPS, 10Gbps fiber optic cables, … Well, whenever I have the time … and then maybe I will get to upgrading it.

CT Clamp Current Meter

I found this old project I did in high school almost 10 years ago. The windows forms app measures the current by using a CT current clamp that plugs into the microphone port.