New Year Reflections

A project log for Tote

Affordable spider robot

deʃhipudeʃhipu 01/11/2017 at 16:150 Comments

Year's Summary

This is one of my oldest projects, and definitely one that I have put the most total work into so far. With the year's end, I decided to reflect a bit about the progress made so far and the way forward.

There wasn't a lot of activity, but some interesting things did happen last year.

We had a workshop in Belgrade, where we built 20 #Tote HaDs. I have learned a lot about how (not) to source parts for such an event, how to run it, what parts are actually hard for people, etc. There were also some improvements to the construction itself contributed by the participants -- but only during the workshop. I'm a bit disappointed that nobody seems to have done anything with their robot after the workshop -- or, at least, I haven't heard about it. I think this is an important point to consider.

There have also been some Tote-inspired builds out there. I helped to build at least two of them. There are even more unfinished projects, but I guess that's normal.

On my side, I released another version of the PCB, experimented with some alternate brains (including the #Tote Zero with a Raspberry Pi), and made one of my prototypes look much better by giving it a chassis and some LED eyes, and a coat of paint. There has been practically no progress on the software side, despite some research on the CORDIC algorithms and servo PWM code. I also didn't experiment much with sensors and behaviors. The step-by-step tutorial is also empty.

Overall, even though some work got done, and even though I gained some experience, I'm not particularly happy with the outcomes of the Tote project. I'm starting to realize that it's not enough to give people a platform to experiment with -- even if they do experiments and improvements, it's all for nothing if they don't share them.

Wrong Goals

I think that part of the problem is that I have been focusing on the wrong parts of the project. I need to pause and re-evaluate some of the assumptions I made, and see where that takes me.

When I was just starting with Tote, I still remembered being a student and not having much of a budget for this kind of projects. So I made lowering the total cost the number one priority (well, apart from having it actually work, of course). As I look at this now, this might have been a mistake. Sure, when you are a student in Poland, price is the number one factor for anything. But it turns out that most people who do this hobby stuff actually don't mind spending a little bit more if that saves them time, makes things more convenient, gives better results or even just makes things look more shiny. If you are going to put hours of work into a project anyways, you don't mind waiting a little bit more to get the extra funds. So I am going to pay less attention to the price (but still try to keep everything frugal) from now on.

By default, Tote is controlled with a TV remote, and has no autonomous functionality. I did that, because I figured it's the simplest starting point, and also shows off the hardware capabilities, leaving any software-side innovation to the users. Or maybe I was just lazy. In any case, I think that this has turned it into a toy, and discouraged actually programming it. There are some other decisions that also contributed to it: the need for an external programmer for programming, the main code written in C++, no easy way to update and debug the code. I think I should start putting more effort into making it easier to actually program this robot, and encourage it more. Fast iteration is the key to good progress. I have become painfully aware of that recently when working on the recent version #µBob biped robot, where I had to physically unscrew and detach the legs to access the chip for programming. That's the best way to make sure nobody ever changes anything in the program unless they absolutely must. So I need to try and remove all the obstacles for programming. And also finally finish the programming tutorial for it.

Simplicity was another design goal (it always is), but I kinda lost track of it in my pursuit of squeezing as much as possible from the small budget. It especially shows in my The Way Forward log a few months ago and the crazy PCB design for Tote Zero. Something definitely went wrong there. I really need to break up the whole design into independent, single-function modules, and I need to work on lowering the complexity of each of them -- preferably using ready off-the-shelf parts and modules. I also need to look into making the assembly easier. One of the goals from the beginning was to not require any special tools like 3D printers or laser cutters -- so that you can make it at home easily. However, I forgot that soldering skills are also an "advanced tool", and that while many people have access to some way of soldering, soldering tiny, densely packed SMD components is not a common skill. So I definitely need to review that.

Sourcing the parts is a problem too. From the start the goal was to use standard, off-the-shelf, easily available components, and I did follow that. However, in my pursuit to make things cheap and also to make it easy to reuse whatever parts you might have lying around, I left a lot of things underspecified. The battery is an excellent example of that -- I'm mostly using LiPos for toy quadcopters, because they are cheap, light and can provide a lot of current. But every manufacturers makes them in a little bit different sizes, with different plugs (they especially love to swap the + and - leads), and generally storing and charging them is a bit involved. Because of that, my designs just leave the battery out, assuming the user will use whatever he has, and will attach it whenever it fits, usually with a two-sided tape, or maybe velcro. That's definitely sub-optimal, and I need to put more focus into specifying the parts a little bit more precisely and using more standard ones. It's also a very daunting task to order a couple of servos in one place, a battery in another place, the pcb in yet another place, the mcrocontroller board in yet another, etc. -- I think that this stops many people from trying this project. Of course, the obvious solution would be a kit, but I don't want to be selling anything... Perhaps I should try looking at Tindie anyways?

Finally, but perhaps most importantly, I need to find a way to disown this project, to make it a brand of its own, and not something attached to my name. I think that most people, when they build a complex project like this, like to "own" it, make it their own -- and not say "I've build Radomir's robot". I haven't figured out how to do that yet. Perhaps I will need to team up with some other similar projects?

Future Plans

I definitely want to continue working on Tote with the goal of crowdsourcing innovation in the area of quadruped robots. There will probably be some large changes, though, as a result of the above goal changes. I will probably use a different development board, something that has shields. I will try to make the battery and power more manageable, and I will put more focus on the documentation and software side of things.