Tiny Air Compressors too

As long as I was evaluating all the air compressors I had around I figured I’d try some tests on these tiny ones..


I think most are from automatic blood pressure meters.. They can build  a decent amount of pressure.


except for this guy. he’s from a Hyundai emissions canister. It was in the evap canister and I think its just bad. I haven’t got my hands on another one yet to compare it to. the car was throwing a code foe a fuel tank leak. I think the little guy just couldn’t pressurize the fuel tank….

Performance Testing Air Compressors

I want to add a small compressor to my truck to keep the rear level. It has air shocks but no automatic control.

If I can find a decent priced string pot I can make it fully automatic. for now I need to select a compressor.

I have a few factory ones and a bunch of aftermarket tire pumps. You cant believe the hyped up ratings so I made a simple arduino test rig to sample the pressure every 100 milliseconds and decided to test every one I can get my hands on….

heres the test setup using a battery, pressure sensor, safety cutoff switch and a few other parts…..

and heres the lot of compressors I grabbed from the junk bin and all the cars outside.

There’s this monster from a Caddy Deville.  It even has the solenoid to drop the suspension attached.

A bare frame from a factory air suspension: Not the fastest but its the one I’m using for my suspension.  Its beefy and runs at a lower speed than the others so it will be quieter… Plus it has two 1/8 npt ports on the head that will make plumbing a breeze.. I probably should print up a belt guard for it.,,,,

a very old compressor from the 80’s


what I thought was a cheapie model but turned out better than expected so I gave it a brand new gauge and 3D printed a new cap for the head…..



A left over from a project. Its a cheap aftermarket car compressor with a 3D printed base…

Real cheapo flea market garbage. wouldn’t hit 200psi if I kinked its hose with vice grips…….

A nice $5 flea market one thats going back in my wagon…


A real surprise is the harbor freight model. It was #2

by far the best and most expensive one I have. Its made by slime. Its big ugly and fast and I keep it in my truck


and the results:

  1. Slime
  2. Harborfreight
  3. Interflator

the rest were about even.


MicroBit Brained Robots

I made a few Microbit Robots for the local library coding class.

This one was printed from scratch.

These two used commercial chassis.

They all use a homemade dual motor driver I had posted on Instructables years ago. I originally designed it for CNC use but it works better in a bot.

The first controllers used the accelerometer for steering. Later I turned this old yard sale find N64 controller into a microbit host.

The board is a perfect fit


Upgrading a K40 for Engraving

I decided to swap my K40 controller for a GERBIL from awesome.tech. I considered the Cohesion 3D too. I’ve been using GRBL CNC controller with a few custom tweaks to the firmware for some time now but I want to see if the extra PWM resolution makes a difference. I just more familiar with the Atmel GRBL code…

While I was in there I added the Pause/Resume/Abort buttons. I kinda chewed up the label while drilling the button holes and the buttons just didn’t cover the mess. I printed a quick bezel to hide it and it made it look even better…

Just to be safe I also printed a small cone shaped washer for the toggle switch that switches between fixed and PWM control. I’ll label that later…

Simple Air Flow Meter

I needed a simple air flow meter for a project so I went out to the garage and grabbed a MAF that was pulled from a Hyundai.

I used a PIC 18F2550 board I had from another project and a small boost converter to make it completely USB powered.

This particular MAF has the IAT sensor built in so it reports air temperature too.

Just breathing into it shows a decent response.


I tested it with a couple of fans I had lying around. One thing for sure that little fan shroud that a printrbot comes with really impedes the airflow.

I made a huge right angle nozzle  for a laser engraver that showed little drop in flow rate…