Category Archives: #arduino

DropBOB Upgrades to “Real-Boy” Status!

So as I hinted from my last post. I have decided to delve right into the world of professional software development. I have started using “Eclipse” as my development platform for my IoT chip – ESP32 by Sparkfun.

To be fair, I didn’t really have a choice. Not all of the features that I need this chip to do have been ported over into the “Arduino” platform yet. I’m sure it eventually will (possibly more than a year, as seen on the prior chip). So, I’m pulling up my big boy pants and learning all the things!

I will be keeping my software open-source. But it will be via the official ESP-IDF. Once I program for this (in C language) I won’t be porting it back into Arduino (Sorry arduino fans).

Continue reading DropBOB Upgrades to “Real-Boy” Status!

Closed loop drop-BOB: the only cold drip coffee maker you can count on!

So I’ve completed my design. I’ve converted my 3d printable files to STL files and have sent them off to the printer: fingers crossed that everything comes back nice … you never know with these types of “compact” housings… Plus this is my first functional 3d print … Everything else I’ve done in the past was not as critical.

With this initial beta release, I can control my coffee maker from anywhere. I can check the progress of how it is doing. and I can adjust the flavor profile depending on how many drops per minute (DPM) & grind type I use. And I can know that it is always exactly where I want it because it’s a closed loop system with constant feedback.


  •  real-time drip-rate monitoring
  •  drip rate selection using micro servo
  •  fully functional wifi-enabled controller (hackable arduino) files shared on Github … 
  •  LiPO 850mAh battery for anywhere brewing
  •  5VDC battery charger (micro-USB same as your phone)
  •  fully customizable monitoring display (it’s your phone) Server & app run by Blynk
  •  use any of your favorite glasses or mugs.
  •  industrial pipe design
  • (planned feature) ETA
  • (planned feature) battery monitor

Drop-BOB – a better coffee maker – Cold Drip

I’ve been working on my software today. I think I have a good base that I will call this version V0.1 … an alpha release, since I know there are a few crashes and more bugs than I would allow in my beta software.
But overall, I’m happy with the result. I have my Arduino code working well with the Blynk platform. From top to bottom & left to right I can: 

  – monitor network connection
  – visually see the servo position
  – monitor up-time
  – see the real time DPM (drops per minute)
  – automatically tweet about making Coffee
  – see the desired drip rate (Set-point)
  – count drops
  – see a history of DPM
  – modify desired drip rate (set-point)
  – Manually adjust the servo position
  – restart when finished
  – simulate a drop
  – and pause the system
All while using a smaller package than when I was using an arduino with an LCD … remember that?
The next step right now is to CAD this “THING” (that’s the real name) … And then place it nicely into my drop-BOB (3d printed design to hold all these components) … It counts drops … and it just bob’s under the water holding thing … kinda sounds cute.

Oh, and also, since my idea is to eventually release this into the world with huge potential for modifications and improvements, I’ve shared my code on my GitHUB. Feel free to make improvements. make comments, or even suggestions that I can implement (note, I’m not a software guy … I juts do this for fun. So go easy on my code).


Closed Loop Drop-BOB … The Cold Drip Coffee maker that could!

So its been longer than I’d have hoped for this post, but I was so torn in my design ideas that I decided to wait a little. I let the ideas settle in my mind and eventually, the inspiration came!

I had a few design criteria to make this Cold Drip coffee maker:

  • Simple & Elegant
  • Easy to manufacture with many “off the shelf” components
  • Hack-able
  • Not offensive to Jenn’s Eye (The wife) … so It can be kept in the kitchen
  • Has a certain “Bobby Style
  • Not too expensive (I’ll probably optimize this later) 
The worst part is that I did not want to settle on any of these criteria … none more important than the other, but all required.
Cold Drip Coffee Maker – “Closed Loop Drop-BOB V1.0” (**Name is a work in progress)
Let me remind you of the progression of the designs prior to V1.0:
V0.1 – the proof of concept
V0.2 – functional prototype
V0.5 – New and improved looks

And now, just recently out of the Alpha stage and graduating to the Beta testing stage: The V1.0 – “Closed loop Drop-BOB” (Name is a work in progress) … The model is not fully manufactured yet (still a few parts on order & to order at the moment). But here is what I’ve got so far:
It all started with the simple wooden bracket shown above. Even though this is not what I want for the final V1.0 product, It helped me visualize what I actually want.

Once I made the bracket, I quickly drilled and taped the brass plug and attached it. Oh, I skipped the part where I cut glass … I’ll come back to that.
This is the part that actually gave me a kick in the ass to make this thing. Since I took apart my original prototype, I’ve been drinking peasant coffee (you know from an espresso maker, like the rest of the world)… After tasting this liquid nectar from the slow drip process, I was all hyped up and wanted to finish this new and improved version.

 It was so good to see this familiar coffee colour (Canadian spelling eh). And since I started making smaller batches, I was able to minimize waste. It takes the same amount of grounds to make 2 shots of extra delicious cold drip, as it does to make 2 shots from an espresso maker … This is for those who think Cold Drip costs more on grounds … not necessarily.

 So back to the glass cutting part. This is the part of the design that forced me to re-think my ways … At first I wanted to make my own water reservoir because I couldn’t find anything on the market that would work with a drip valve (open at the bottom & the top). I also wanted to potentially control the temperature with a peltier plate … but that will be for a later version.

I eventually came to the conclusion that I should modify a container to suit my purpose. Diamond tip glass cutting bits are a little expensive (but who am I kidding … I love buy new tools).

I did the entire cut on my drill press, with the glass inside another glass filled with water. Make sure you have no air bubbles.

The hole came out nice. Only a few little chips were missing, but nothing I can’t deal with by using some washers and O-rings.

This part was the most tricky … and the reason I spent over a hour standing in front of the brass fittings part of the local hope depot store.

Turns out that compression fittings are not easy to combine with other types of fitting .. like MIP, and Pipe treads, etc … I needed some distance between my valve and the glass ,so I can add my little beauty of a “Close Loop” servo control box (more on this later) … You see, the next great idea I had was not to connect anything other than a single hole to the bottom of a glass (or, steel, or wood, or coconut, etc). This allows me to use virtually any container that I can make a 3/8″ hole at the bottom.

Seems to work nice. Got the distance I was looking for by connecting the 1/8″ compression thread valve to a flared copper pipe, to a female MIP, to a 3/8″ OD short brass pipe and connected all that with some O-rings to prevent leakage … I feel like I can optimize this later for cost and simplicity, but good enough for V1.0.
Here’s where all the magic happens. This little box is less than 2 square inches … And packs the servo, the valve, and the photo-interrupter all in a tiny little robust package. (The wireless controller ESP8266 will also be fit into here shortly … if it ever arrives)
Once this think is fully built, I should be able to control and monitor the drip rate from my smart phone … from anywhere in the world!

Cold Drip Coffee – THICK AND RICH!

So here’s a progress update on the development of my cold drip coffee machine. After my last post, I had determined that the only way to get this coffee just right, was to control the drip rate. 

The idea was to use either a photo-interupter or a pietzo electric disk to detect the drop. Since I need the servo to be used for feedback control (think back to your “Control systems” classes). If I did not have any feedback control, even after perfectly setting up the drop, the drip rate (DPM) would become less and less as the volume of water above the valve becomes smaller (simple fluids 1 class, of which I had to take 2x because of a terrible teacher & an overachiever’s workload).
So, as Lee’s Electronics nor Main electronics had any readily available photo-interrupters, I settled on the pietzo sensor … It turned out to work, but it happened to skip every third drop or so … “Not good enough!”
So, I turned to my next favorite electronics distributor Digikey. I used them for work to purchase the odd chip here and there and just love how cheap and fast they are. I ordered the GP1A57HRJ00F photo-interrupter and received it the next day as I got home from work. 
So off to the grinds I go (literally). I held off on cleaning my room as you can tell, I was just so excited to make this new sensor work. And work it did. Really well too. This thing has a 1-microsecond response time … that is really really fast.

So after throwing together a cheapo setup using my trusty wood clamps and some junk around my shop, I managed to get a reliable, easy setup.

As of this writing, I’m at 8483 drops and 16-hrs … bottle is only about half way filled (see first picture). My controller is set to 8-DPM and averages around 8 to 9 due to the play in the servo. But it really does work.

 Just look at this thick, sludge of a coffee. I haven’t tried it yet, but I have a feeling I’ll need to dilute it … Its just so THICK!

Arduino GSM Expandable Vehicle Connection Project

Working on some code today. I discovered the many awesome uses of switch(x){Case(0):} loops in the Arduino code. Here’s how they work:

if (buttons & BUTTON_UP) {                       // If a button is pressed and it is the Up button
          menu = menu – 1;                                 // Adjust the menu item to be the one before
          if (menu<0) menu=3;                            // If you went too far up, cycle through to the bottom
          switch(menu){                                      // Start the switch loop using the “menu” variable
            case 0:                                               // In case the menu = 0
              lcd.setCursor(0,1);                           // Place the LCD cursor at the bottom left
              lcd.print(“1-ChangeSensTrip”);         // Print “1-ChangeSensTrip” on the LCD
              break;                                              // Need this break, otherwise it will continue
            case 1:

Here’s my code on Github if you would like to use it: And don’t forget the licence agreement. Personal use only!

I’ll clean it up when I have time.


Arduino GSM Expandable Vehicle Connection Project

Had some time today to put a few touch-ups on my project. I added a DB9 connection (currently using only 4 pins … I may expand it in the future).
I’ve also modified some code so that it only turns the LCD on when the driver is seated. The sensor is still functioning but it draws less battery this way. I don’t think the baby would want to know weather he is seated, the car temp, and the time until he may be in danger anyway. That’s more for the dad to know.
I managed to use my car inverter to run a soldering iron and a hot glue gun … I did notice a drop in voltage though over the 5 min of use. I don’t recommend doing this for too long without your engine running.
Now I just need to work on the menu options.
I’ve even done a quick calculation that the arduino would last a few months, basically sipping battery, while sensing. So not too worried about battery usage at this point.

Arduino GSM Expandable Vehicle Connection Project

Didn’t think I’d blog today but due to work circumstances I was nearer to home at the end of the day. Figured I might as well put a few hours in before school.

I managed to pick up an LCD kit from Lee’s. Solder it together, test it and incorporate it into my Arduino just in time for school.

And since I don’t really learn anything in school, I decided to bring Jenn’s laptop and do a little coding at school.

I got all the data now showing up on my LCD and I started working on the menu and UI.

Arduino GSM Expandable Vehicle Connection Project

Working late last night, I managed to figure out got to take apart my seat covers and insert my capacitance sensor.

Oh ya also, note to future self, don’t use 10 awg ground wire … I had to change all the wire routing in my car because it was to hard to work with.

I’ve also placed my Arduino in a protective case. Attached behind my rear view mirror with Velcro.

I’ve t-tapped into my constant-on 12v line from my ceiling light. This way I can have my vehicle constantly monitoring. I’ll be purchasing a lithium battery booster today until I can assess the power used by my system … I also haven’t setup any safeguards against battery drain in my code yet … I’ll have to look into that.

Today, I have school. So tomorrow I’ll have to go to Lee’s again to get a new LCD display. I would have had this done by now but my first one burnt out during the original accidental short (read: blowup). Also, when I bought my second one I didn’t read that it was for the raspberry pi.

Arduino GSM Expandable Vehicle Connection Project

Today, since I’m pretty hung over, we decided to go grab lunch at our newest craft beer place. So many choices…

Using our newest member of the group, Luca, we tested the functioning of my device with a baby seat with baby and all.

We filmed him left in my car in the baby seat. He cried, I got a text saying that he may be in danger. It was awesome!

So not only did the project work beautifully, I got some feedback from some awesome friends who actually have a baby.

Now time to make the project nicer looking and “wife friendly”. What I mean by that is that you don’t want to install a device in you car that will create a constant nagging that you have wires sticking out everywhere.

And just a little advertisement for a new tool I just purchased. The 8pk-371 write stripper and crimper tool. This thing is amazing all metal construction. Made with quality and reliability in mind … All of this time I was stripping my wires with my front teeth. My dentist will appreciate.