Let's Make Robots!

SplatBot MkII

Write LMR and squirt things

Sleeker and with twice the firepower, SplatBot Mk II has some obvious improvements over the original. Noticably the water bottles and pumps are on the chassis making the cannon much lighter and more responsive. I've also doubled the storage capacity and pumping power. each pump is individually controlled for multicolour writting. Both videos can be viewed in high quality mode.

The first video is the most recent and is for the purist. Directed from afar :)

He sounds like an excited cousin of R2D2 but this is actually the sonar range readings converted to sound to help test that the sonar is working properly.






The second is my earlier experimentation with video editing software syncronised to some suitable music with our new logo hastily added before uploading :D












The chassis is the same as the original with some meccano supports to hold the water bottles (not shown). The two pumps and a DC-DC converter have been added to the back.

The DC-DC converter is configured as a voltage step up current regulator. This means that the output is a higher voltage than the input and the current is regulated to control the brightness of the LEDs.

The LEDs used are 0.5W 10mm green and white LEDs. They are very bright, in the video's they are turned down to minimum brightness. The white LEDs in the water bottles are for lighting up water that has been coloured with food colouring. Unfortunately the only video with that working was the two colour LMR attempt. The dye had to be very dark to show up well on the sand and did no light up as well as hoped. I plan to do a night video that should be better.

I've attached the code for SplatBot although it's incomplete. The IR tracking routine will be re-written to suit the next sensor design and the LMR routine has been written in a less than efficent manner to make it easier for me to tweak the font. If I'm ever happy with it then I'll condense the code.

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Heh, the video is pretty stable and cool with a robot controlling it, the Splatbot is AWESOME, I'm planning on making a firefighting robots too, later (By later i mean WAY later). But hey, still I can get inspiration from others! :D

Hi OddBot-

 I am curious about the 6 wheeled Chassis you are using. Was it custom or something off-the-shelf?

If you look closely you will see it is mecanno. I used mecanno for most of my robots in the early days. Later I built a homemade 6WD chassis that became the prototype for Wild Thumper. You can read my tip/walkthrough here and build your own.

That is one Awesome Robot, just one question, doesn't the Sun emit Infrared as well, how does SplatBot differentiate the Sunlight and the fire? I really like the movement of the water canon! :D

This robot was built 3 years ago. The IR sensor you see here is the original IR compound eye that is now sold by DAGU.

Yes this sensor cannot tell the difference between sunlight and fire. If you look at my fire fighting robot it is using thermocouples instead of phototransistors.

The thermocouples range is still limited and depends on the thermal heat radiated from the fire. When I get time I want to add Chris's Wii camera to this robot so it can spot fires from a greater distance and then use the thermocouple sensors to confirm that the camera did detect heat and not some other IR source.


really cool robot and i can't believe it wrote 'LMR' :p. I really like that IR tracking module, it looks so clean.


Awesome work to be honest. My question may sounds a bit silly, but how did you connected the EZ1 maxsonar to the picaxe28? is it the same as srf ultrasound series.

No the EZ1 sonars have both digital and analog outputs. Aside from power I just had the analog output connected directly to the Picaxes analog input. This is the best method in my opinion as it is quicker. Although I never had any serious noise issues it never hurts to use shielded cable for your analog inputs.

I'm working on a project inspired by you, and I've bought a simular looking pump, as I couldn't find a battery powered water gun either.

Is the pumps output made for tubing that are 5mm measured on the inside? I'm sitting looking at the plastic tube joiners that came with it and they seem to be to wide to function as a nozzle. Were the "black plastic fishtank tube joiner" you mention in your original splatbot text something else?

Right now I'm experimenting with wind screen washer nozzles, but they give more of a thin spray than a jet... 

PUMP OUTPUT: The fishtank tubeing seem to come in two types. A flexable plastic or a silicon rubber type. I used the rubber type as it is softer and more flexable. It was difficult to stretch it over the pump connections but it stretches a fair bit. You could also try silicon rubber fuel lines used for model engines and whippa-snippers. Otherwise you may need an adaptor.

NOZZLE: The black joiners had an inside diameter of only about 1.5mm. This seemed to be fine for the pressure developed by my pumps despite being underpowered. It was nothing fancy. You might want to try plugging the tube with some polymorph instead and just drilling a small hole in the end. Start with a 1mm hole and work your way up untill you get the right flow. I used a set of drills designed for circuit boards. They came in a pack of 0.8mm, 1mm, 1.2mm, 1.5mm, 2mm and 2.5mm.

PRESSURE: The nozzle is dependant on the pressure developed by your pump. Make sure you have a breather tube in your water container so you don't end up with a negative pressure inside. Have your pump below the container if possible and make sure there are no air bubbles in the pump. Because I refilled my container by pushing water back through the pump it helped to prevent air being trapped in the pump.