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Custom PCB Prototypes work well !


After giving up on solder paste and stencils, then realizing “acid” based solder flux will eat your board I’ve made the first working prototype of ZoneRobotics custom PCB board.

It works very well 20fps and crystal clear image. No scan lines, even with a 10 inch ffc 24 pin connector between the board and the camera.

We will be respining this board once more and if there are no huge issues with the next version it will be what we launch on kickstarter.

Look out for update videos and tutorials about how it works soon !

Keep an eye on my youtube channel

Testing the zBot on the “Cloud”


Setup a test where my zEngineExample service ran on a free trial of linux VM. Unfortunately I used 5gb of network traffic in 2 days and expired my trial before I had a chance to do a lot of investigating.

To begin with the web client is the slowest most troublesome of the clients, on top of that the cloud server was somewhere on the east coast. There was so much latency between the web client and the cloud server that the messages timed out and were thrown away from the zEngine service. From what I could tell there was something like 300ms of latency to connect and do anything, this is unacceptable for real time applications

I had the zEngine service connecting even if there were no active clients, so this caused all kinds of traffic when no one was even using it.

Will have to retest and next time:

  • Make service disconnect when no clients
  • Test latency between me and cloud server
  • Use lowest resolution
  • Test native clients

Back to BlueTooth ! (Edit: or not)

Just an update the bluetooth seemed like a good idea at the time with the options available, but I made a lot of breakthroughs with wifi and finalized the bot to use wifi. I now get over 1Mbps and can get up to 4mbps, there is no need to in most cases though since I max out the camera at 20fps. I will be releasing another article soon.

—- Old Article

As I have moved along with wifi I started to have an enormous desire to allow the wifi to send all of the information into a browser instead of a custom application I write. This way the user simply starts up their browser and points it at the wifi bot and they get a video stream and a robot they can manipulate. From there the same controls and commands you can send with the ZEngine java API you could send over the url to your bot. This will allow developers to use pure javascript or other languages to interface with the bot. But this model does not allow any bluetooth, so I thought to myself what do I do with all of this bluetooth code I have written and this nice system I already have ? It must be useful to someone ? So I decided to split the bot into three, one for bluetooth, one for wifi and one for long range. You can read about it here

Long story short I want to finish the hardware and the software by September. So my goal is to get all the bluetooth stuff that I already had working and make it work again and finalize it. The hardware will have support for all three bots but the first version and the software will use the bluetooth modules. This way I can finalize the body and the hardware and have a fun toy and then start long term development on the other bots.

I had big issues with the bluetooth before being inconsistent with the firmware. I would write drivers for one module then order some more and they didnt work the same. A really smart guy from France named Byron has documented how to burn a good or at least consistent version of software onto the HC-05 modules. I have made contact with Byron and he has graciously agreed to help me with the project should I have issues.

So, for now its full steam ahead finalizing a bluetooth bot, for better or worse !

ZEngine and PC client is here, Android client is almost done

Hello All ! I know it has been a while since my last update. I am actually working and making very good progress. As always the facebook page is the most up to date and the BEST way to contact me !

In a nutshell I’m almost done with Bot 2 of 4. It works well and I’ve added several new features. Whats left to do for Bot 2 is clear and Bot 3 will be even better.


I have built a “engine” that does all of the heavy lifting for communicating with the system. Connecting, sending and receiving message and even other stuff like system statistics are all take care of by the engine. The engine is fully documented and has been stripped down as much as possible to keep it simple and easy to use.

The engine can be used in a Linux or Windows java application, or in android. The same exact engine is integrated into all of the software that is developed on to of it, no matter what the platform.


I have added support for up to 4 servos. Each servo is independantly controlled by sending it an angle of up to a tenth of a degree. The angles are from 0 to 180. This works well with the micro servos and has me thinking of ways to control the camera as well as how to add arms or appendages.

Analog to Digital Conversions

I had previously only 1 ADC that worked on the hardware. I had thought eventually I would get to three. However after investingating it again I was easily able to get 6 to work. So now the unit has 6 ADC conversions updated about 10 times a second. One of them is used for the battery, this helps you know when the battery is getting low. I also plan on using another one for the charging current, but this will be in bot3.

Battery Situation

I was amazed that all of this works on one single CR123 battery at 3.7v. As of now it lasts about 30 minutes before the software will notify you that the battery is low. As with most electronics when the battery is low it misbehaves more. I dont know if I will continue to try and use only one cell. I built a extra battery pack in case I need it, this would give me about 3 hours of battery life.


I have also investigated the battery charger and understand how it works. I even made a test circuit. BUT working with the IC is nearly impossible, it is too small. I burnt up the one I was testing with and moved on. Theoretically it looks like everything is good and it *should* work. Hopefully I can also address this in bot3 if I have any charger IC’s left. I have not been able to find a larger IC replacement that works the same.


I’m using wifi communication, which for some reason maxes out at about the same as the bluetooth 230Kbps. It is however much more stable and powerful since you can connect it to your router and forward it across the internet. You would have issues pushing bluetooth across the internet.

I still support the bluetooth modules, and even another wifi module. I dont know how much support I will have for the other modules. I think support for them will be on a “as needed” basis. However, as of now there is working drivers for all the modules I have used.

In bot3 I plan on switching to SPI which will give me a much greater throughput, up to 4Mbps with the same wifi interface. I will also have to add commands to connect to your router and set passwords etc.


There is a small set of commands that can be sent to the bot, In both the java example and the android example I expose the entire tree of commands. I have also added several commands to do things such as set the camera resolution, set gpio, slow superloop and much more. I’ve wrapped all of the commands into a system so you can simply call the function with the name of the command as a string and send it off.

For example to send a message to slow the internal loop of the bot down by having a delay of 500 milliseconds you can send this command (assuming you are connected).

                    BotMessage bm = new BotMessage();
                    // slow things down if debugging !
                    bm.updateMessage("CONTROL", "SETDELAY", 500);

That is all the code needed to create and send the message. It is the same for all of the other commands that control pwm, servos, camera etc.


I have built this platform similar to Bot1, but I used the polulu 30T tracks this time so I can compare and contrast the two. I also attached lights to the front.

Java PC Example

I have written a java application that shows how to use the ZEngine. This application exposes all of the controls to the user. It is meant to be a starting point for whoever wants to develop a specific application on top of the ZEngine. zenginepcexample


I have a short and semi confusing video using it on Youtube. It shows all of the components functioning together.

Android Example

I do not consider it complete until the Android software works as well. I’m almost done with the Android example code. It also exposes all of the functionality to the user. The picture you see below has all of the controls in a “sliding drawer”, so when you hit the control button at the top all of the controls are out of your sight.

It shows you the status of all gpio and the ADC’s, and when you bring up all the controls it gives you control of 8 gpio, 4 servos and the custom command tree (which is everything).

To “drive” I have implemented left and right motion controlled by two pointers on either side of the screen. So if you put your thumb down anywhere on the left side of the screen and move upward the left motor will move forward, same for backward and the right motor. I’m not sure how easy it will be to drive this way, but if its not fun I’ll put in the simple analog joystick control again.



Zbot System RoadMap

Torn between perfection and “something that works” we have decided to draw the line on different features in different versions.

Version 1.0 Description

This version will be a board attached to the stm32F4 Discovery board. The board will contain all of the IC/connections for two motors and the camera. This way we can develop the games and SDK without setbacks related to creating complex circuits and the “slippery slope” of making things better/faster. We will have the full functionality to move around and “shoot” with lights. The main things we will lack are the ability to move the camera up and down, the lower cost associated with 1 board and the lack of high speed uart connectivity.


$15 Stm32F4 Discovery Link
$10 OV2640 Board and Camera Link
$7   HC-05 Module with board Link
$25 Motor/Cam Connector board TBD!

Version 2.0 Description

This board will include a custom board layout where we connect directly with the camera module. There will be one “mainboard” where the stm32f4 chip connects to the 24pin camera connector directly. We will incorporate the required LDO’s and circuitry to interface directly with the camera module, saving us about $3 per board. The “mainboard” will have everything you need to get video over uart to whatever you want while exposing the gpio/pwm/i2c similar to the Ardruino. We will also add functionality for faster bluetooth and possibly wifi connectivity.


So going from version 1.0 to 2.0 the main thing that will be developed/finished is the SDK and the “development platform”. The finished product will be very useful for hobbyist and those developing proof of concept (senior projects, etc). It will be a circuit board with motors/track and camera. The end user will be able to develop directly in android or java to have the unit preform the desired operations. For version 2.0 we are going more for the consumer market. Version 2.0 will be an enclosed product with no exposed circuit board.

Doing things this way should get us something usable and reproducible within just a few months. We wont have to spend the next 2 months developing our own circuit board.