A short video demonstrating a quick and easy way to build a charge protection board for 3s (3 x 18650 batteries in series). 3 x 18650 in series will give you around 12v. The board will help protect the battery pack from overcharging, over-discharging, over-current and short circuit.
I’ve been research designing circuit boards design and tried a few different such as eagle, ki cad and came across easyEDA which is perfect for newbies like myself. Its simple to use, the SMC (Surface mount components) selection is all tied in. You can order a PCB and have all the component (well most of them) soldered at the manufacture JCL without you have to do any soldering at all! Take a look at the video below for a quick demo
A live docker tutorial for the Sheffield Hackspace. A run through through what is docker, benefits of docker, popular docker containers for Hackspace members (Node-Red, MQTT, Octoprint, Grafana, InfluxDB, ROS), running image as containers and how to develop using visual studio code docker plugin.
I needed a new bag for my Brompton bike. All the bags were very expensive, £70 for the basic bags so I did what any maker would do and started on the journey to make my own bag. There was a few challenges:
1 . Find a way to connect the bag to the front carrier block securely.
2. Find a cheaper bag that i could modify easily and thats water proof
3. Work out if anything else was need, e.g. bag strengthening.
I started by look on thingiverse for 3D printed Brampton carrier block, its always a good place to start to see how other people have attacked the problem. I didn’t find anything. I set work to design one myself using fusion 360 – Matt SB gave me a helping hand to get started with as its the first functional 3d object I’ve printed. I came up with the item below after a few iterations printed on my Aldi 3D printer.
The next challenge was to find a bag. I search on the internet and i purchased a bag from aliexpress for £4 to test the process out. The test went fine and I used the bag for about a year but the wear and tear took its toll on the bag so I bought a better quality bag from decathlon shown below. This is the bag that i will describe on the rest of the blog.
I’ve got the carrier block designed and the water proof bag. Now I need to attach everything and make sure it wont damage the bike/contents of the bag. The back board in the bag was a bit bendy and I’m carrying my laptop to and from work so I wanted it to get there and back in one piece. To strengthen the back I bought a A3 clear polycarbonate makrolon plastic panel Sheet 3mm thick from ebay. This went down the back of the bag to strengthen it. I sawed it to shape to start with and then bent it using the hot gun in the hackspace. This gave the bottom of the bag something solid so the laptop or other items in the bag wouldn’t sag and hit the front wheel. I also added some neoprene foam to the bottom of the plastic sheet to cushion any items put in the bag.
The next task was to attach the bag to front carrier block. I did this using a hand drill and screwed it together.
I wanted a separate area for the bag.
We’ve finished building the prototype of the LinoRobot and have an understanding of how all the software and hardware fit together.
There was a few issues along the way and ill summarize what we’ve learnt:
- ROS and the navigation software requires a faster machine than the current VM. Now we understand more we’re going to build ROS on the direct hardware.
- The Raspberry PI doesnt have SWAP memory enabled by default and ROS ran out of memory when first starting ROS. Enable SWAP for initial ROS startup and then disabled it.
- We cheated the first time by using ubiquityrobotics ROS image the first time and we’ll probably cheat again, it makes setup a lot easier 🙂
- Don’t use very cheap cheap motors as they don’t give similar results and the robot goes around in circles. We bought some more expensive motors this time so hopefully they will move when we want them too.
The parts have arrived and we’re now getting started on the second robot.
Sheffield Hackspace has setup and installed a LoraWAN (The Things Network) gateway. LoraWAN is a new technology that enables small amounts of data to travel large distances with low power and the best bit of it is….its free!! This is being used by universities, corporations and hobbyist a like to transmit data such as air quality, traffic, temperature, gps informational ect. from battery (or wire) powered devices that last up to 10 years and more.
Come to the Sheffield Hackspace to learn about this new technology and make use of the gateway to prototype your idea. If you want to make your own gateway and add to the things networks, come and learn how to do that. See if your area has a gateway installed by clicking the link here.
For our gateway, we used a Raspberry Pi and RAK 831 to receive multiple frequencies at the same time. For some unknown reason the RAK 831 use to switch off occasionally so we’ve added a on/off relay (as can be seen in the photo) to power recycle it automatically/remotely when when it stops responding to the Raspberry PI. Hopefully we’ll find the root cause.