<h1>Closed loop drop-BOB: the only cold drip coffee maker you can count on!</h1>


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

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SKU: DropBOB-Original-Custom-Order Category: Tags: , , , , ,


A cold drip coffee maker that is set and forget. the closed loop system allows for a stable drip at exactly the rate you want it. The Open source software allows you to make it yours. The off-the-shelf design allows you to modify and augment it! The always connected WIFI design lets you control it and modify parameters on the fly from anywhere.

The community base supports you and helps you grow!

Important Note: Currently in Beta phase. All units hand built. Lead time may vary, production and purchase runs grouped to keep costs down. Exact colors or features may vary.

Additional information

Weight 25 lbs
Dimensions 24 × 15 × 15 in
Cold Brew Attributes

Custom, Handmade, DropBOB Original, Wood Accent, Industrial Chic Style



  • Drip control from 3dpm to 100dpm with closed loop control
  • Holds 500ml to 1000ml of water
  • food-safe Copper and Brass piping
  • sparkfun ESP8266 wifi controller
  • 3 position toggle input switch
  • Adjustable height from 0-30-inches

User Manual

DropBOB CoffeeMaker Instructions

[toggle title=”Physical build”]

Physical build

Begin by opening the packaging and disposing of the environmentally friendly packaging (Please recycle)

Once all disposed of, screw the Black Steel pipe into the wooden block until tight. Don’t worry, these are compression threads, they get tighter as you screw in.

Now, make sure the 4 feet of your block are level with the surface you want to put it on. They screw in and out.

Now take the Black Steel Tee that is connected to the 3-d printed “spaceship” looking thing with a red valve handle. unscrew the handle until you can fit the Tee over the steel pipe. Adjust to desired height and then tighten the red valve handle.

Now place your “water-tower” on the plastic “spaceship” contraption, with official “DropBOB(TM)” contraption (the square cube of “Insert Colour you purchased here”). Note that in order for you to do this you will need to slide the 1/8″ brass tube through the allotted slot in the “spaceship”.

There, the hard part is done. Please pat yourself on the back.

Now you can place the bottle in the pocket. Wait, first, slowly rub your fingers on the blue surface created by heating Molten Epoxy until the wood fibers explode with joy at just the right moment to lock the happiness into its forever solid (and smooth) surface. OK, now place the bottle in the pocket.

Remove the Eco friendly Cork and place the white funnel in the mouth of the bottle. Take some grounds (Recommended dosage is the equivalent of 1 espresso Spoon — equivalent = 2 tablespoons = 30 ml — per cup that you plan to make) and place this in the provided thin mesh re-usable filter (hand wash only). Now place a small paper tissue (Scott Towel) on top of the grounds (this is to make sure the drop doesn’t just make a hole through all the grounds overtime). Now you can place the filter/Coffee-grounds/paper-towel assembly directly in the Funnel. It should be a perfect fit.

Now plug the provided USB cable with power converter into the wall and the micro USB end into the side of the “DropBOB(TM)” cube.

You should hear the servo turn to position, and shortly should see some drops coming out. This is normal, don’t panic. Just hold onto your towel. If you can’t find your towel, then you haven’t read enough sci-fi books.

At this point you should also notice the blue blinking behind the “DropBOB(TM)”. This is normal, This indicates that the device is calibrating. This calibration process could take several minutes. It is slowly closing the value until the desired Drop Per Minute (DPM) is reached (Default is 6). Also notice the toggle switch. This switch has a (on)-off-(on) configuration. The brackets mean that the switch will not stay locked in that position. Pushing the switch down and holding for a few seconds should put your device to sleep and close the valve as well (helpfull for refilling). Pushing the toggle upwards will wake the device and start the code running from the top (note here that attempting to wake the device while already awake will force a restart of the code … how would you like it if someone tried to wake you when you were already awake!).

The control logic embedded into the ESP8266 make it so that any disturbance is “naturally” brought back to a steady state. Any errors or issues, should always automatically self correct (over time … some large disturbances may take several minutes, up to an hour even if you really screw with it). Now go enjoy your day … you’ve read enough …

[toggle title=”Connecting the DropBOB(TM) to your wifi & Phone”]

Connecting the DropBOB(TM) to your wifi & Phone

Download Blynk from Android or Apple stores for your phone. Open the app, Create New Project, make sure the “Hardware Model” is set to “Sparkfun ESP8266 Thing” then tap on the “AUTH TOKEN” and it should automatically copy it to your phone’s clip board. Click Create.

Now Make sure your DropBOB is plugged in. After a few seconds it should start broadcasting an Access Point that you can connect to from your phones wifi (if this is not happening, see the last topic “Factory Reset”).

Using your phone, connect to “Drop-BOB”, wait for your phone to authenticate, it should automatically take you to a web page to begin setting up your connection. Basically, you need to tell your new DropBOB what your wifi network and password is … its brand new, like a child. It needs to be trained!

Click on “Configure Wifi”. Click your Wifi name. Type in your wifi password. Then long click on the “blynk token” field to “paste” the “AUTH TOKEN” you originally copied to your clip board. Click Save.

This basically saves the Wifi and Blynk connections to hard memory, it will remember this even if you leave it powered off for a long time. This is a one time step, unless you factory reset.

Now your DropBOB(tm) should be happily working away at the default settings.

[toggle title=”The front-end Dashboard controls, Blynk”]

The front-end Dashboard controls, Blynk

By now you’ve probably asked yourself … Where’s all the controls? How do I tell this super-smart-almost-artificially-intelligent-device-thing to do my laundry … We’ll here’s the fun part. Your “DropBOB(TM)” should now be connected to your wifi and broadcasting its status to a server located somewhere in the world. Blynk also has a great community of builders and hackers. This app lets you customize your “Drop-BOB(TM)” dashboard for you to control anything you want. The limitation is only with the amount of code you want to modify. But not to worry, there has already been enough code written to get you started.

Open you Blynk App, on your new project, click the plus (+) button or swipe the screen from right to left. This will display all the awesome widgets you can add. Go ahead an add anything you like. each of the widget can be configured after you add it to you screen by clicking on them. The Virtual PIN number that each output is attached to is shown below (these functions & variables can also be found inside the code running on your DropBOB, more on that later):

// Blynk Virtual Variable Mapping //

#define SIM_DROP                                         V1
#define SETPOINT_DPM_VIRT_PIN            V2
#define DPM_SLIDER                                    V3
#define UPTIME_VIRTUAL_PIN                  V5
#define RESTART_BTN                                  V6
#define DPM_avg_VIRTUAL_PIN                 V7
#define PAUSE_BTN                                       V8
#define SERVO_SLIDER                                V9
#define DPM_VIRTUAL_PIN                        V10
#define RE_TUNE_BTN                                 V11
#define DropBOB_DEBUG                            V12
#define LCD_VIRTUAL                                 V13 // attach LCD to Virtual 13 complex mode
#define DPM_INSTANT_PIN                        V14
#define TERMINAL_PIN                               V15
#define SERVO_MIN_PIN                             V16
#define SERVO_MAX_PIN                           V17
#define MODE_DROPDOWN                       V18
#define MENU_DROPDOWN                       V19
#define CLEAR_SAVED_SETTINGS           V21
#define IS_DONE_VPIN                               V22
#define BOTTLE_SELECT_PIN                   V23
#define ALLTIME_DROP_AVG_PIN           V24

Now go crazy and build yourself a dashboard! You’ll be able to control and see your “DropBOB(TM)” status from anywhere in the world that you have internet! This is otherwise know as the IoT (Internet of Things) Revolution. Right now we are only at IoT 1.0 … Similar to the way the internet had its Internet 2.0 phase, the IoT will also be going through its 2.0 phase as more and more people start using it. So get out there and enjoy your ridiculously delicious cold drip coffee! you coffee snob!
If you need more info on the Blynk App & its Widgets, please visit Blynk.cc

If you want to use an already built dashboard, you can go ahead an use mine: http://tinyurl.com/gry8e5k, you may have to purchase some additional “Energy” as I have a pretty extensive setup. If you’ve built a great setup, feel free to share the picture and the link to a copy of your setup in the comments.

[toggle title=”The software, Arduino program”]

The software, Arduino program

Under the hood! Not afraid to get your hands dirty? Well, here’s where you’ll need to roll up your sleeves and push up your glasses because this is about to blow your mind!

Start-up you computer and download this software: Arduino and install on your computer. Open up Arduino, then go to the Preferences (File > Preferences). Then, towards the bottom of the window, copy this URL into the “Additional Board Manager URLs” text box:


Now go to “Tools>Boards>Board manager” and type “ESP8266” in the Search box. Select the latest version and click install (this may take a few minutes). Go get yourself a coffee … Oh wait, probably only have a few drops by now. I kid, soon, you’ll be able to taste the delicious nectar that is Cold Drip Coffee.

There … should be done by now. Now go to my Online GitHub (Online repository where I keep my always updated Community developed “Braaaains”). If you want to become a Community developer, please download the GitHub software and learn how to Fork the Repo (Not required for usage, but greatly appreciated). Once you have the Drop-BOB.ino file downloaded to your computer (click here if you’re having trouble downloading the file: master.zip, this downloads all the files in the repo in a zip) you can open it up (the “Drop-BOB.ino” file inside the zip) with your recently downloaded Arduino software. Now you can see the code behind the matrix. Give yourself another pat on the back.

Now you can connect your “Drop-BOB(TM)” to your computer if you haven’t already (Through USB). Make sure the Arduino settings under “Tools” have the Correct Board: “SparkFun Thing ESP8266 Dev” (The DEV is important). Make sure you set the CPU frequency to 80 MHz (the 160 MHz is not supported for Servo operation. Make sure the Upload speed is 115200 (you could go higher, but it may cause errors at some point). And then make sure you have the right port selected (You can find out which one is the right one but unplugging the Drop-BOB(TM) restarting the Arduino software, checking which ports are there, then see which ones appear when you plug it in. Another good way to check is by Clicking “Tools>Serial monitor” if something pops up and maybe you see the “Drop-BOB(TM)” output … should be a few lines shown after every drop.

Once you did all that, you are all set to click “Upload”. It should compile, then proceed to upload. Any errors here and you did something wrong. You should hear the servo tick gently for several seconds while you see more and more dots on the arduino screen eventually says that the upload was successful. The servo valve should again take “position”.

Wow, that was a lot, how about a third pat on the back …

[toggle title=”Troubleshooting”]


I’ve included the controller documentation in case you decide to do some tinkering. Soldering iron required. Here’s the board info: sparkfun Thing DEV

Please note that the “DropBOB(TM)” will run without the front and back cover, this is useful for troubleshooting or just generally seeing what is going on. Please watch your fingers for pinch hazards and always wear the appropriate PPE for the task. If you are unsure of what you are doing, STOP, call you mom and ask for help.

[toggle title=”Resetting to Factory Defaults”]

Resetting to Factory Defaults

This part takes some quick hand maneuvers, so you’ll need to mentally prepare for this. You’ll need to enter the Konami Code ( ↑ ↑ ↓ ↓ ← → ← → B A ) … Kidding. Its only up momentarily, then hold down until the led flashes rapidly, once it flashes rapidly you can let go. All setting should be reset. You can check by seeing if the “Drop-BOB” wifi access point is broadcasting again.

If your phone or computer doesn’t automatically redirect you to the login page after you connect to the Drop-BOB wifi, you can manually go to that page by typing in a browser window (It’s a known issue that some devices have issues with captive DNS which this DropBOB device is using).