Security Cam Robot, This Droid Is Watching For You. Jazzy Power Chair Frame




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I have picked up a few Jazzy power chairs and pulled the seats off of them. I will further remove stuff that I don't need. I have seen people hack the original motor controllers but I feel like I am better just selling the original on Ebay and buying one made for DIY building instead. My first power chair base project I used a Sabertooth 2x12 ,but I do have a couple other generic controllers I picked up that may work just fine. I will post some pictures, thoughts, goals and parts I have to work with so far. Any input is cool.
12 hour test update:

Watchdog met it's first goal! 12 hours unmanned / no humans , I am checking Watchdog from remote desktop and it is still going strong, I started the first test at 11:30 pm last night. I cannot see the battery meter from here, but I will be able to check the battery around 5-6 pm. Hopefully Watchdog can make it to 11:30 tonight.
Almost 24 hours from the time Watchdog was powered on , I still have over 24 volts!
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.6 volt loss since yesterday night!

I am very happy with the efficiency of the equipment. All cameras have been recording and the sabertooth and the 5 volt dc to dc converter are being used.
Doing some research I found charts that indicate the voltages of batteries to consider Dead so that they will not be damaged and still have hundreds of cycles
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24.2 has 50 percent capacity left and 23.02 has 10 percent left and certainly considered dead so this should be the cutoff voltage for the health of the battery. I will let the bot run overnight tonight as well and see where we are at. It would certainly be great to break a 48 hour runtime before hitting cutoff voltage.
So is this robot physically moving or navigating the house at night or sitting in one position? If it’s not moving what is the saber tooth being used for?
Sabertooth is on idle but powered on. The Robot is not moving for this initial test , I wanted to get some base numbers as most the time the Robot will watch and wait , it doesn’t run around continuously.
Ok, Update on the runtime test, the robot was idle but all the equipment except the IR leds ( which consume 24 watts max) , motion and ultrasonic sensors. You can see the pictures of the starting voltage and the end voltage. Doing research I found 11.8 is considered dead for a 12 volt battery. or 23.6 when two batteries are together. I notived after 24 volts the rate of drop increased and was quicky down to 14 volts for the combined batteries. Still enough to power the robot , but bad for the overall life of the batteries! So in the future I am considering 24 volts " dead".
I wanted to test the battery longetivy, My goal is 24 hours without human intervention. Here is the starting voltage. ( I later found out that my batteries were not full when I started)

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25.2 apparently is not 100 percent full, maybe these batteries were being broken in.

Excellent news ! After 24 hours runtime I still have battery life left.

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24.6 volts from the 25.2 starting voltage. That is an average of .025 volts drop per hour.

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Here is a reference chart I am comparing to for the battery capacity, take in mind I am running 24 volts.

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after about 32 hours I was at 24 volts even but I wanted to see if I could make it to an even 48 hours. I pulled the plug on the battery for recharge at 42 hours.
I charged both batteries on two 3 amp chargers for 12 hours and now they read a higher combined voltage than before! So apparently when I started this test I was only at about 80-85 percent battery capacity.
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sample screen shots of night cam, pardon the cluttered play room.

Watchdog forward cam on initial boot

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Watchdog right cam

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Watchdog left

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I forgot the Ip to the rear cam so I didn't grab a screen on that one.
This is amazing work. I missed following your work this past year or so while you were on robot sabbatical. ;)
Thanks Dave I appreciate that! I enjoy your company and spectator-ship.
Nice work! I have used the same wheel chair base for robots before. Great platform to work with.

You do amazing work.


Ok tiny update , one raspberry pi keeps crashing after a few hours , only one is a problem so I bought a replacement that I will swap out. I also ordered 4 Pi zero W to see if I could use those instead to get the job done and gain some space as well as more battery life. I already received the permanent Power Sonic 12v 35ah batteries. I charged them overnight and just plugged them in. These are nearly twice as heavy as the old batteries! 10 pounds more each , 20 pounds more total.
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Josh, be sure to use a new SD card in the pi that is crash. I had one on my network that was acting wonky then refused to boot, and it was the SD card, not the pi.
Hey tech guru , I used a different mico SD card and started from scratch with formatting, partitioning and writing the OS. It worked for about 4 hours and died agian. I used a new spare Sandusk ultra high endurance 64gb card. I have a fresh board I am swapping to in the AM and probably sending this Pi back as this board only has been a problem child.

Also I have 4 of the Pi W zero on the way and I will test them , if they do the job I will swap them to free up physical space and lower the overall current draw a couple amps. The pi zero is only 1ghz cpu, so it uses a bit less power.
Ok , another exciting night! All the IR leds have been soldered and run with the pi cams. Faulty pi was swapped for a new one and appears to have fixed that problem. The gps is now actively tracking the robot in my back yard area. Now to cross my fingers all goes well overnight , the insides stay dry and power needs are met.
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OK So I found that after I soldered the IR leds in, that the raspberry pi now draw a great deal more power and I believe causes brown outs from the 24v to 5 v dc converter. So I ordered two more and I will split the load of the raspberry pis and ezb so that they stopped having a voltage drop. As far as the cams all are working well.
OK I will ramp this back up soon, I had to replace the Sabertooth controller because I am an idiot and accidentally applied 24 volts from the power rail to the 5 volt input Vcc, and I let the smoke out. I have the replacement and now things have slowed down since the there are no more contests we are working on. The PI are being swapped for Pi Zero to save space inside the head. I will swap the full size ezb for IO Tiny.