Bit of a shot in the dark here, but I figure its a good place to ask!
I’m currently building a Hexapod robot for my degree dissertation project, and since the budget is limited to £300 for all costs, I have had to make a lot of cost saving shortcuts, or look far and wide for the best possible deals. I have completed design and construction of the chassis based on the tower-pro MG995 servo (as this is the absolute cheapest servo I could find).
The SSC-32 was a great purchase as it is a relativly cheap and very powerfull servo controller. I have an order for 20 MG995 servos about to go through for about £100, but in all honesty these servos are crap, as the 4 I have been testing and developing with over the last few months are getting a bit ropey already.
Does anyone know of a company that might sponsor or provide servos to students on limited budgets, or know of a servo which is a similar size to the MG995? I had very limited success with Hitec; enquiries stopped at their american offices who promised to contact the asian offices to see if they could help…
The odds of getting Hitec to sponsor an individual student project is slim.
A hexapod can be built with HS-475 Hitec servos if your dimensions are similar to the Lynxmotion Hexapods.
They can be had for around $12 to $20 each, depending on where you look.
Ebay users tend to liquidate them in packs of 2 or 4 fairly cheap because they come standard with some radio systems and are not used.
It would be your next cheapest and reliable solution.
Sorry to say but if you buy 20 MG995 servos, odds are at least 2 won’t work at all, 3 to 5 will be jittery and the others will only work until you apply some load to them repeatedly, at which point they will curl up and die. The MG995s are just terrible servos. All the towerpro’s are. That is why they are so cheap.
If you really want to keep the cost down, I recommend trim the amount of servos. Proportionally, the cost of servos will dominate the overall cost since the SES brackets and chassis are a fraction of the total costs of “many-servo” bots.
Have you considered a 3DOF quadropod? These require 12 servos instead of 18 for the 3DOF hexapod.
If you are set on hexapods, you can consider 2DOF hexapods, like the hexapod minis. You’ll only have 2DOF per leg, but it’s still able to walk and turn and only use 12 servos instead of the 18 required for 3DOF.
The cheapest and most reliable way to go would be the HS-645MGs. These things are relatively cheap for what they put out. The 475s can be used in place, but they are the absolute minimum (which means you cannot put much payload, other then the electronics like SSC-32, botboard and batteries).
I highly recommend not sacrifice servo power for quantity when it comes to cost. If you buy underpowered servos for your application, you buy twice.
I have been testing a TowardPro MG996R (uppgrade from995) and it performs very well. MG996R is digital I think and it has only 135 deg of travel, to bad
