LCD shield compatibility with servo and P&T shields

Discussion related to "under the hood" OpenMV topics.
User avatar
kwiley
Posts: 107
Joined: Fri Dec 21, 2018 5:22 pm

LCD shield compatibility with servo and P&T shields

Postby kwiley » Wed Mar 27, 2019 5:13 pm

If I'm understanding the pinouts correctly, the LCD shield should work with the servo shield, which relies exclusively on the I2C pins P4 and P5, but not the pan & tilt shield, which utilizes the servo pins P7, P8, and P9, which would double up on the LCD's use of P7 and P8, right?

As a follow-up, would I be correct that with the LCD shield, the M7 or H7 could directly control a single servo, without any additional shields, via P9, albeit without position reading capability (which the servo shield doesn't support anyway, but the P&T shield does)?

So the advantages of the P&T shield are position reading and dead-man-switching and the advantage of the servo shield is far more servos and LCD compatibility, right? I realize I asked about the servo and P&T shields a long time ago, and I have perused the response in that thread, but I'm still trying to grasp the "point" of the P&T shield over the servo shield.

Am I correct on any or all counts here?

Thanks.
User avatar
iabdalkader
Posts: 933
Joined: Sun May 24, 2015 3:53 pm

Re: LCD shield compatibility with servo and P&T shields

Postby iabdalkader » Thu Mar 28, 2019 11:29 am

If I'm understanding the pinouts correctly, the LCD shield should work with the servo shield, which relies exclusively on the I2C pins P4 and P5, but not the pan & tilt shield, which utilizes the servo pins P7, P8, and P9, which would double up on the LCD's use of P7 and P8, right?
Yes, the servo and LCD shields both use P7 and P8.
As a follow-up, would I be correct that with the LCD shield, the M7 or H7 could directly control a single servo, without any additional shields, via P9, albeit without position reading capability (which the servo shield doesn't support anyway, but the P&T shield does)?
Yes, when using the LCD P9 is free to control a servo.
So the advantages of the P&T shield are position reading and dead-man-switching and the advantage of the servo shield is far more servos and LCD compatibility, right?
Yes but I think the main advantage of the P&T shield is that it has a regulator with a 20v input so you can use say a 7v or 11v battery, and get 5v to the servos.
User avatar
kwiley
Posts: 107
Joined: Fri Dec 21, 2018 5:22 pm

Re: LCD shield compatibility with servo and P&T shields

Postby kwiley » Thu Mar 28, 2019 11:51 am

Ah, okay. Thanks.
ScottM
Posts: 55
Joined: Thu May 30, 2019 2:12 pm
Location: Ottawa, Canada

Re: LCD shield compatibility with servo and P&T shields

Postby ScottM » Fri Jul 19, 2019 11:44 am

I had a dream that I could use the camera with a pan/tilt shield and LCD display. I wanted to mount the camera on a pan/tilt servo setup and have it find and track an April tag and automatically center. I can do that, but I thought that it would be cool to have the display show a live preview of what the camera was seeing. I guess that I can still do it if I use only pan or tilt, but not both. Not ideal, but I'll try it.
User avatar
kwagyeman
Posts: 3258
Joined: Sun May 24, 2015 2:10 pm

Re: LCD shield compatibility with servo and P&T shields

Postby kwagyeman » Fri Jul 19, 2019 12:26 pm

You might be able to get away by not connecting the reset pin on the LCD shield. Not sure if it will work without it. But, we did that for the TV shield and it was okay.
Nyamekye,

Return to “Technical Discussion”

Who is online

Users browsing this forum: No registered users and 5 guests