a lot of topics...

PCB:

if you "re-brand" the pcb as a dual frequency divider, one can use one pcb to 1/2 to frequencies (quad encoder) , or can a single PCB to 1/4 divide a single phase or frequency clock. It's a very specific item/requirement, and is only needed in your build due to the Kangaroo + encoder solution.

If you endup building a few you can try to sell it as a Kit (PCB + components) or assembled ready to use. To check if there's market/need one place you can try: www.tindie.com

I would order only 10 piece or something to test the idea, and only then when you have the full idea working (Bot + Slam + Software) and your are happy with the components i would evaluate if moving with a single PCB or multiple components.

off course you can try to sell a small batch online before embracing quantities.

I like the kit and assembled idea. Save you some time and work too. Nothing like the smell of solder in the morning ... lol.

Unfortunately, or fortunately I guess, the board is so small that ordering small quantities is very difficult. I could go through China, but then there are other issues. The place I found that has really good ratings charges a flat rate up to 60 square inches, and is in the US. Pretty much everything I found here in the US says USE THESE GUYS. You can put as many as you can fit on the 60 square inches, and you have to order a minimum of 4 of these 60 square inch sheets. I'm good with it at the price I am getting it at. It will give me about 160 of these to mess with and figure out what I am going to do with them.

I do like the thought of putting 50 up for sale. If that happens, great. If not, they will end up being used in Rafiki's or other things later anyway.

I also like the kit idea and have from the beginning. The only problem is a lot of people will burn up the chips by not knowing how to solder them. If I add a socket (which still can be burnt up) then it doubles the price of the components. The good news is that these chips are pretty cheap so if someone needed to replace theirs, it is cheap for them to do so. I would probably solder the socket on though if I went that route.

IDK, right now finalizing the PCB design. Hopefully it will be complete tomorrow.

I do have a question on that though...

Is it important to you that the pin outs all come out in a single header location or do you mind if they come out from different pads on the board. For example, A,+,B and Gnd would be labeled but would not be in a row. It would be expected that someone would either put pins in these locations or would wire a wiring harness into these points that fits their needs. What are your thoughts?

This is my opinion, very biased and based only in what I've seen so far, and my day job is software development (I'm not a robotics engineer).

I'll use different words to avoid hurting the existent products.

I would never choose SB or K for to build a robot product from zero, the reason is the price.

SB, K are very popular products when you go to the RC world, and when you build solutions using build blocks like E Z R. The way E Z B works forces you to have different operational blocks, and you have an overhead/management/communication layer over each component.

For example Arduino builders, why you need a K when you can build the logic using code or even a open source library (PID control).

Why i would need a SB, when i need only a H-bridge with some heavy amps.... etc.

Regarding the motor (if i got the right one) M R 3 0 0 = $130 only the encoder H E D S 55 40 = $49

It seems very good motor, but if i have one for $40 with encoders justifies the difference ?

If i go with the $40 i don't need a frequency divider.

The value will depend on your choices, but i can't justify if spending more in hardware it will make the difference until the software is ready.

If the software specs requires that particular combination, there is nothing to argue.

Building a product for end users, the price is very important...

Also, thanks for the link to Tindie. I will check that out in depth. looks like a perfect place to market this.

Pins Alignment, a row is the preferred method, at least you can use strip cables and plastic cases with multi pins and everything gets clean.

I know the headers/sockets and other simple materials raise the price, if can provide 3 options, kit, assembled, assembled + headers.

Browse the Tindie community to have an idea of the offers, there a lot makers but there are also a few non makers (listing the 3party products from china).

I would pay attention to the makers.

Quote:

Regarding the motor (if i got the right one) M R 3 0 0 = $130 only the encoder H E D S 55 40 = $49

Tje MR300 comes with an encoder. It is a 5505. (from Zagros) The MR300 is a Globe IM-15 spur motor geared 127.78:1 with an encoder added. To buy this motor by itself without the encoder runs about $200 on-line. An encoder could be added which would cost about $40. This brings this total to $240 per motor.

Buying from Zagros, you save about $100 but end up with a really high count encoder, that a lot of systems are going to have trouble keeping up with. For say $6 bucks you can fix this issue, or you are going to have to replace the encoder if you want this motor. Replacing the encoder costs $40, so now you have saved $60 over buying the motor without encoder, and the encoder separately. To do this, you have to be comfortable removing the encoder and replacing it with a new encoder, but the only encoder that is readily available is a 100 count encoder. You have taken your resolution down by 5 times. The 6 dollar fix lets you save an additional $34 and allows you to have only 1/2 the resolution decrease.

Now if you take this into a mass production situation... time = money and money = money. Reducing the cost of the robot build by this much is considerable. Even if you didn't use a roo or sabertooth, and drove this from an arduino and an LBridge, you have extreme resolution still, which might be far more than needed and require you to use larger variables/memory and cycles. Maybe cutting it by 5 is a great solution. Maybe cutting it by 4 or 2 is a great solution. Having options is a good thing, and definitely is a good thing when it comes to large production quantities.

I'm using one motor that costs me $40 with an encoder, why going with a $130 ?

I'm not familiar with those motors, did you pick them for a specific reason ?