Some work over the last couple of weeks, albeit small. I have now added a 9v power connection, so that I can develop code while connected to a power brick. Also added a connection panel to the rear of the robot, this allows better connection to the Arduino and reset switch.
Added some simple mounts for three reed switches. These are then connected to an analog pin via a resistor ladder. I have created some simple code that stops the head from turning once the magnet has reached a switch, this should allow for some testing of head position and mounting.
Once this part is finished, it will time to create a simple program to allow Hero Jr to be driven. Now that I can telnet to the Z80 this should make things easier.
As lockdown now starts to ease, updates on this project may not be as frequent. I do feel that this robot has much scope as a development platform, much like the original bots. I have lots of ideas, and development of the head including an input panel and LEDs will be next.
A little more 3D printing and the basic layout for the head is complete Need to workout how how to find the forward position. Running out of pins on the Arduino!
New motor arrived today, although much smaller than the original the gearbox really helps. Made up a quick adapter plate from some scrap aluminium. Seems much better, will now replace the rear sensor from a micro switch to an optical sensor. This should help as the micro switch was not being reliably triggered.
The RC2014 has now moved it to it’s new home. Much work now need to be done on tidying the wires to motor control boards and the Arduino.
Hero Jr has taken his first steps. He is not so keen on a deep pile carpet, but fine on the kitchen tile floor. This is due to the steering steeper motor. He needs something with more torque to turn the wheel on carpet. I have ordered a 71:1 stepper and gearbox it’s quite a small motor but I’m hopeful this will work. Next steps are to fit a cutoff switch and look at fitting the RC2014 inside. I need to tidy up the wiring to the Ardunio as I think this will be kept to handle the control of the lower motors. I looking at using the remaining pins to interface with a RC2014 I/O board.
The basic frame is now finished and ready for some testing. Using a Arduino Micro Pro to test the motors will provide a quick and easy platform for creating some test code. The stepper motor for the wheel turning is just temporary until a better motor and gearbox can be found. Using two L298N driver boards for control of the two motors. I may leave the Micro Pro in as an interface to the motors from the RC2014? The next step is to creat some stop switching so the wheel knows it’s location.
Finished the wheel assembly today. The axels are on adjustable mounts so that Hero can be levelled, once the rear motor has been finished. I did a quick test to see how it drives, and it’s all looking great! (So far, famous last words)
I have most of the inside structure worked out now. The four uprights will be supported at the top by some removable clamps. This will allow me to slide on additional supports for the CPU module and anything else that needs adding. These clamps are yet to be designed as I want to assembly the central part of the robot first. All the motor parts have been assembled and I have used some parts salvaged from an old printer, this includes a couple of brass bushes. Next steps are to test a stepper motor I have from the same printer to see if it has the required toque to steer the drive wheel. I have dug out an arduino mega for quickly creating some code on.
A day of careful planning and it all starting to look good. Can’t wait for this one to take its first steps
With all the fixing parts now printed assembly can start. I will need to sand parts to the correct angles to fit the side panel and glue these in place. All the weight will be on the internal metal frame, so I hope the glue will be strong enough!
Wow that took some time, but I have finally finished printing all the large parts. The head has been glued together with just the panels to add. The top ones will be removable to allow some flexibility with what I decide to use them for.
Printing and gluing of the main body parts has now finished. I still have some gap filling to do and have found that epoxy putty given to me by a friend works very well. Printing of the head is also going well with around half of the parts done.
Made good progress on the motor mount today. I have now finished printing all of the main body parts, so now it’s time for the head. This has around 14 components, so much printing still to be done. I also managed to glue another part to the front panel this will allow me to finish this part soon. Square tube looks like the way to go for the internal structure so next will be the design for this, and the second half of the motor mount.
Going to look at some code today to use these i/o expanders. I only have one more part to print for the body, should just have enough filament left to do this tomorrow. Then we are on to printing the head part. I need to think about how parts are printed so that I get good detail for some of the LED openings.
(I have also made some good progress on the box file layout)
Everything starting to come together now, still much more printing, glueing and sanding to go.
The printing continues, but I have most of the parts for the body done. I have now glued the two front panels together after a light sand with 400 grit wet and dry paper. Using plenty of water seems to give a good finish as this keeps the plastic cool while sanding. I used a five minute epoxy and this just gives enough time to align the parts before curing. I have a couple of gaps to fill, and then it will be on to painting and more sanding.
I have now also finished the second i2c board and will start to investigate I/O expanders.
With printing going well, and I’m almost ready to print one of the larger parts (1 Day 3 hours). I’m currently testing the new wake up the sheds on fire system. It was quite straight forward to modify a smoke alarm as the model that I have has lots of test pads on the bottom. One of these goes high to low when the alarm sounds (it drives the led). A Raspberry Pi in side the house talks to the one in the shed, to see what the current status is.
I have now finished building both SC113 backplane boards, although I managed to solder the end connectors on the wrong way round! This creates a problem for pin 1 now being the wrong end for one board.
I have one more of the I2C boards to finish. This will allow me to test devices before moving to the Hero Jr. I now have two CP/M systems both running SCM 1.1 and I have tested cloning the compact flash card to move from the development system to the Hero Jr. This should allow me to easily backup my work and move any finished code around quickly.
My Development system is currently RC2014 Mini with CP/M and 5 slot backplane. I using CP/M 2.2 with the following software.
ZDE16 - Editor
Z80ASM - Compiler
DDT - Debug
Windows 10 laptop with Tera Term (Colours set to Green)
Next steps are to look at building the case for the Hero Jr. I’m going to start sanding down the parts ready for glueing together and coating, and the spray painting.
I’m looking at replicating the original drive mechanics, as I like this idea :-).
Some good progress made on the Hero Jr. Ordered two boards from smallcomputercentral this will give me 12 sockets plus two end connections. First board stuffed with CPM parts! Also making progress on printing the body.
Printing of the Hero Jr parts is going well, thanks to my Ender 3 Pro and OctoPrint!
But waiting until 1 a.m. is not going to happen again. Need to build a alarm system to work along side OctoPrint. Smoke alarm on order from Amazon, with some python I should be able to create an alarm in the house just in case we get smoke when printing.
Just about finished the model of the Hero Jr, not a complete reproduction but good enough for me.
Next steps are to print it all, this make take some time as most of the parts take around a day to print.
