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Canada
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Resolved Resolved by ptp!

EZ-B Iotiny Use In Omnibot 5402?

I have an Omnibot 5402 that I would like to control movement and move the arms and head to start. I was thinking of going with the smaller EZ-B IoTiny due to cost difference and lower port requirements. The EZ-B IoTiny has 8 digital ports and a dedicated camera port.  Since all I want to do is run the motors for movement by using an H-Bridge and 3 HDD Servo's for the arms and head movement, the IoTiny should work.  If later on I add a Camera and Ultrasonic sensor and a Display/LED, I should still be able to do this with amount of ports on the IoTiny.  Any thoughts on going this route?


Related Hardware EZ-Robot EZ-B IoTiny
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Synthiam
#1  
The solution is Elementary mathematics.

Quote:

Since all I want to do is run the motors for movement by using an H-Bridge and 3 HDD Servo's for the arms and head movement
EZ-Robot H-Bridge:
https://www.ez-robot.com/Tutorials/Lesson/44

Quote:

D0 - Green (Left PWM)
D1 - Blue (Left Trigger A)
D2 - Purple (Left Trigger B)
D3 - Grey (Right Trigger A)
D4 - White (Right Trigger B)
D5 - Black (Right PWM)
You have 2 ports left (D6, D7) for 2 servos.

Quote:

If later on I add a Camera and Ultrasonic sensor and a Display/LED, I should still be able to do this with amount of ports on the IoTiny.
Option A)
Ultrasonic Sensor:
"Over the counter"
2 digital pins

Option B)
EZ-Robot https://www.ez-robot.com/Shop/AccessoriesDetails.aspx?prevCat=9&productNumber=6
1 digital pin
 
LED  one color : 1 Digital Pin

So:
6 - EZ-Robot H-Bridge
3 - 3 x Servos
1 - Led
1 - EZ-Robot Ultrasonic Sensor
Total = 11 Digital Pins

Quote:

I should still be able to do this with amount of ports on the IoTiny. Any thoughts on going this route?
Unless 11 is equal to 8. I don't think you can fit all with an IoTiny.
Canada
#2  
PTP: Thanks for explaining the need for 6 Digital pins just for the H-Bridge.  I definitely need the EZ-B V4 then, even if I decide to keep it simple for now, I would use up all the pins with just an H-Bridge and 2 servo's and no upgrade room with the IoTiny.
Synthiam
#3  
Just wanted to add that you can use an H-bridge with 4 or 5 wires instead. 4-wires removes the PWM speed adjustment completely but it's still fully functional. With 5-wires you can have one wire that changes the speed of both sides of the H-Bridge at the same time. 6-wires is only used for independently controlling the speed of the motors, which is not always required. 

You can also use the IoTiny I2C port with a port expander to get more I/O. I don't have an example of that but I'm sure you could find code out there.
Synthiam
#4  
You also have access to 2 x ADC ports on the I/O tiny that can be used for distance sensing. I know that Maxbotix has Ultrasonic sensors that can output an analog value.
Canada
#5  
Jeremy, thanks for the additional options mentioned.  I may still go with the V4 as it's the best to build on and may be simpler if I add on sensor's later.
Synthiam
#6  
If you remove the pcb from a servo, it becomes a speed controlled hbridge via one port. And, the continuous rotation servo Movement Panel makes it easy. 

I like using servo pcb’s as tiny hbridges. I’ve convinced Jeremie to do it often in his robots. 

Ps, I recommend a camera right away rather than waiting. A robot without a camera isn’t a robot:)
Canada
#7  
Thanks for the tip DJ, lots to digest before making a choice....
My Omnibot is an original one I had as a kid, no camera, but I definitely considered it a robot in 1984!