Oscilloscope DSO138 Case

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!

Comments

[Palingenesis]

Very Nice.
Here is how to ad some text to the front of the case.

[stratoreaper]

you might want to add access to the on-board square wave oscillator. Nice case, an output for the oscillator is simple, just make a hole and stick a bit of wire or better make a small wire loop that connects to the board where the square wave test pad is located ( upper right side, next to the power connectors).

What that would do is enable to calibrate new, nicer probes that you can get for the oscilloscope. Real oscilloscope probes are not that expensive anymore and are a good investment. They have a tunable capacitor to adjust their impedance to the 'scope input and to do that you connect the measurement lead to the square wave source and you keep adjusting that trim cap until the rising and falling edges of the square wave register nicely , no (large) overshoots, no rounding at corners (almost, ok...) and no "ringing" on the straight portions . Once that is done, the probe is tuned and the scope is ready to measure stuff with the new probe. Why get a nicer probe? A variety of reasons: lower noise, easier access to terminals and pins, some probes have X100 attenuators, and lastly 'cause it looks so good!

[geekrex]

nice project , i would do same for all my circuit if i had a 3d printer