A few weeks ago I made a circuit with ac power and had some trouble with it. I only have a multimeter and not enough money to buy a real oscilloscope (>300$) to solve the problem. So I decided to buy on internet a little diy oscilloscope for less than 20$. Of course I'm not able to work with high frequency but for arduino projects with pwm and bridge rectifier at 50HZ, it's widely enough. With this oscilloscope, I designed a case with some feature like a battery holder to make it portable and a support. In this tutorial, you will find all the steps to make one.
Step 1: Tools and Materials Needed
You will need a 3d printer with filament (if possible 2 colors), a drill with different size of drill bits, sandpaper, a solder iron, screwdrivers and glue.
For the materials:
-a DSO138 Oscilloscope, you can find one for 20 $ on Internet.
-9v battery with connector
-a slide switch
-some copper wires
-4 screws salvage on toy
-a m4 screw of 15mm with a butterfly nut
Step 2: Print and Clean All the Parts
I designed all the parts with sketchup by measuring all the dimensions, you can find them all here: Case for DSO138
I printed the case, the support, the bracket and the battery holder in red PLA. The buttons and the slide switche caps were printed in white PLA. Print all the part with the settings you prefer, I 3d-printed mine with a 0.4mm nozzle, 0.2 mm layer height, 25% infill and with a brim of 3mm to stick better on the bed.
Once you 3d-print everything, remove the brim, sand them, clean holes with a drill and make sure all the parts fit together.
Step 3: Modify the Oscilloscope
To fit in the case, you must unsolder the battery connector. After, solder 2 wires on the pins of the battery connector of the PCB on the back side. This wires will then be connected to the 9v battery.
The other step is to unsolder the led, connect 2 wires to it and connect these wires to the previous connections of the led. Pay attention to the polarity of the led, it must light up when you turn it on!
Step 4: Assembly
Place the buttons in the case and put the 3 slider switches caps on the oscilloscope. Before putting the oscilloscope in place, glue the led in the hole of the front case. Expand the holes for the screws with a drill if you need it, depending of the size of your screws. Put the back case and close it with 4 screws (I used salvage screw from an old toy).
Step 5: Place the Battery Holder and the Support
Take the other 3D printed parts. Glue the battery holder on the back case in the center, you should send the surface first to make it stick better. Glue the bracket of the support too (look closely where I glued mine). Assemble the support with the m4 screw and the butterfly nut.
Step 6: Connect the Battery
Glue the slider switch on the top of the back case. Solder the 9v battery connector and the 2 wires that you soldered before to the switch. I used some heat shrink tube with the solders. The last thing to do is to write the name of the functionality of the buttons. I did it with a permanent marker.
Thank you for taking time reading my project, I hope you like it! It's one of the first tutorial I made, please leave a comment to give me advice. Thanks!