Where to buy:

Thank you for considering to purchase my arduino shields and gadgets! Your contribution helps me keep up the free codes and libraries I have been maintaining. My purpose of selling these hardware is not to make money. Consider time and effort as an individual on designing hardware and software, sales, packaging and support, there is no/little monetary gain. I am just happy to provide hardware and software supports to those that really enjoy their arduino experiences and push their experiences to a new level.

Each gadget or shield has its own page and there is also a link to purchase directly from my blog site, or to purchase from one of the following online stores.

Online store introduction:

Several online stores carry my arduino shields and gadgets. Please click on their name or picture to be redirected to their websites. is an online open-source hardware bazaar. Many well-known arduino hardware designers have their stores at inmojo, selling their latest designs. All sellers, myself included, ship orders from their own locations, world wide.

Not all designers maintain their own online stores, where they can decide what they want to sell. When they sell through an online store like sparkfun, they don’t have control over what they can sell and how soon they can list them for sale. Inmojo is like ebay for hobby electronics, providing the quickest way for designers to offer newest designs to their customers.

If I have successfully prototyped a new design and have parts for kits, I can offer it for sale at inmojo right away, where it will take weeks to get an established online store to agree to sell it, put materials online, send in the kits, and correct mistakes they make on descriptions. For example, my most popular item, the phi-2 shield, which has sold several hundred kits (including phi-1 shield), is not considered interesting enough by sparkfun. I don’t want to speculate why but a fact is they have very high margins on parts I include in my kits, like LCDs and I don’t πŸ˜‰

Ruggedcircuits designs and sells their own arduino shields and gadgets and they carry products from other designers as well. Ruggedcircuits is also a well-known member of the arduino forum. The store is in Michigan USA, where all orders are shipped.Β  Their name represents the aspect of some of the circuits they design.

Although Dipmicro is no longer carrying my kits, I’m keeping their information since they are a good parts supplier. Dipmicro is physically located in Canada but has been able to ship from USA by crossing the border at Niagara’s fall. It is a smaller online store but it carries tons of basic parts at incredible discount. If you have cross-compared dipmicro and sparkfun, you will find that some items sparkfun sells is 10 time as expensive and AFAIK, there is no difference in quality. If you want parts and some common ICs, you should visit them. Many arduino forum member root for dipmicro.

Using phi_prompt or phi_interfaces library in commercial products:

The libraries are free under GNU GPL V3.0. There is no need to make any purchase however you are using them. Hail open source! If you want to integrate the libraries in a product that you will sell for money, please obtain a license for $30, which covers the current and all future updates of both libraries. This purchase grants you license to both phi_prompt and phi_interfaces libraries. Additional programming assistance can also be purchased at store but please contact me first regarding the type of programming help you need before purchasing.

22 Responses to Buy

  1. Hello. With (20X4 Serial LCD keypad panel – Phi-panel). I can make a vt100 terminal. Some code written for it. I am interested in your products.


  2. Fabio says:

    Hello, i’m very interesting in Phi-2 shield 20X4 but i have a few dubt that ios the best choice for my progect. I would make a chronometer with many countdown and it must be precise at 1/100 of second. Your Phi-2 shield 20X4 use the DS1302 but i must have the DS3234. It’s possible to change the chip or the are other problem? Sorry i’m new in arduino world’s.
    Other dubt is: how many pin are free for use for over input/output?
    Is it possible to change the diplay and make a GLCD in future?
    How much cost the optional 24LC512 eeprom?
    Can i make my own chronometer programs run on my arduino and pass to phi2 only the diplay, menu, read and save parts?
    Many compliments for the work, i’m sorry for my bad english.

    • liudr says:


      Replacing the character LCD with GLCD will not be possible with the current shield. GLCD needs 13 arduino pins. Once you use a GLCD on an Arduino UNO, you don’t have many pins left for anything else (2 pins for program upload + 13 pins for GLCD so 15 pins used and 5 left for everything else).

      The DS3234 is on SPI bus, and DS1307 is on I2C bus so they can’t be swapped. You will need 4 pins to control this RTC, while you only need 2 for DS1307. Hope this helps.

    • liudr says:

      I just realized I only answered half of your questions:

      There are just a few free inputs/outputs left and they are documented on the documentation in a table.
      the 24LC512 is available at (it’s one of the biggest in the industry in US)
      Price is $2 but maybe there will be some expensive shipping charge for overseas delivery.

      I think if you want to run your own program and pass the display and menu etc to phi-2 shield, that is fine. If you really want to save pins (all shields use many pins), I suggest you get a serial LCD backpack (without the LCD) and connect to it via a software serial port (use 2 pins). Then it will report back to arduino what button is pressed and arduino can just Serial.print() info to the screen. Even phi_prompt library elements (text area, menu etc.) are embedded in the panel for easy use such as Serial.print(“Please select:\nItem 1\nItem 2\nItem 3\n~”), with a few more characters as special command will make the panel render a menu and it returns you which option the user selected, nice?—phi-panel/

      There is even a faceplate option for the serial backpack:
      serial backpack with face plate

  3. Igor says:

    Dr. Liu, I live in Croatia and I’m interested in backpack kit. Can I connect to this kit 16×2 and 20×4 LCD screen? Can you sell me just backpack kit? or pcb with programmed mcu?

  4. Moises says:

    Dr. Liu, we would like to purchase 100pcs can you offer us a better price? Please consider the shipping to Mexico. Regards

    • liudr says:

      Hi Moises,

      Thanks for your interest! I will email you so we can start a discussion on what hardware. Yes, I ship worldwide. When we are talking 100pcs, I will ship insured and with signature requirement so it will get to you safely.

  5. George says:

    Dr Liu, is an assembled version of Phi-2 available for sale with GPS module and EEPROM. I am not very good at soldering and would prefer to purchase an assembled unit. Also, I would need help with changing the code to only write GPS data to EEPROM when a button is pressed. Would this be covered by your Software Help – One Hour of Programming? Please reply to my email address.
    Thank you.

    • liudr says:


      Thanks for your message. I have one assembled Phi-2 shield with EEPROM and GPS connector and 20X4 display ready to ship. If you need a 16X2 display version, I will have to order the GPS connector and assemble it for you. The GPS module is this one, which is probably better if you purchased it yourself since I have only one and am currently using it.

      Here is the connector I put on the shield:

      If you want the assembled 20X4 display shield with the tiny GPS connector also soldered on + EEPROM, I can sell you one unit at $30 (shield kit) + $10 (assembly+connector) +$7 (shipping). International shipping just went up the past couple of weeks 😦

      The 16X2 version is cheaper, $24 (kit) +$10+$6 but its display area is limited. If you want Time, EEPROM space left/latitude/longitude/altitude etc. the 20X4 display is great for it.

      Regarding programming, do you want the GPS coordinates displayed on screen and then press a button to save the current values to EEPROM, maybe with a time stamp from the real time clock or the GPS time code (if you’re in UK, it makes more sense to you since GPS all uses Greenwich time)? I can certainly do that for you. With the raw materials I already have (several project code) I think I can write the program for you within an hour ($100).

      let me know what you think.

  6. Johannes says:

    Hi Dr. Liu,

    I would need 2-5 (would start with 2) of your assembled 16×2 phi-2 shields together with face-plates (like this:
    When do you expect them to be back in stock again?
    I would be happy if you could contact me by E-Mail.

    Thanks in advance and best regards,


  7. Jerome Cloutier says:

    Hi Dr. Liu,

    I am building a project, and would like to use your menu system to replace my ugly switch case coded menu, I use a 4*4 keypad with a I2C pcf8574 expander so that I don’t use up all my I/O’s. Can you please point me in the direction on how to modify your lib’s to use the inputs from the I2C keypad. If you could email me I would greatly appreciate it,


    • liudr says:


      I didn’t personally make this type of mod to my library system but you are welcome to try. With your I2C keypad, are you able to get the key press (or no key press) by calling a getKey() function just like the most popular keypad library? If yes, you may be able to create a class that inherits from keypad class or just clone a class from matrix_keypad class and replace its key sensing functions with your I2C keypad’s version. I don’t have your expander so I can’t test code for you. I can give you some help still.

      An alternative to my menu system and I2C keypad is my phi-panel system that have the menu system integrated on its on board processor. Take a look to see if it interests you πŸ™‚—phi-panel/

      Everything is done by serial port and arduino sending text messages to the panel. There are panels with integrated keypads and backpacks on LCDs to connect to matrix keypads etc.

  8. Paul says:

    Hi I’m new to this. I have a vibroplex semi-automatic bug. If I buy the Phi-2 with the code software preloaded from you can I wire my bug into the unit and sent code displayed on the LCD?

    • liudr says:

      If the vibroplex semi-automatic bug can be driven by 5V signals, then the speaker output can drive it. Otherwise, you need some transistor to drive the bug. What voltage will drive the bug?

  9. Bob Katz says:

    Dear Dr. Liu: Your blog is a great resource! I’m just getting started with Arduino, but in a previous life decades ago I was good at embedded assembly language programming of 6502 and 8051 and I know my hardware and 74-series logic, so I’m not a complete novice. :-).

    I’m not sure how else to contact you so I’m asking on your blog if you please. Do you have a cover available for the Serial 20X4 LCD keypad panel – Phi-panel? I’ve seen a photo on inMojo but can’t find it again. With button caps, a hole for the LCD…. Do you have any left that you made, available to sell? Thanks! Bob Katz.

  10. Pingback: Phi-shield revised and released | Liudr's Blog

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