So it has been a while since I’ve posted here. I’ve had allot going on. My ma had a heart attack and then tripple bypass so the last 4 months have basically been taking care of her. I got my telemetry RX built up and tested. Currently using it as a wireless thermometer. I still need to lay out the board for the TX that will go on the rc truck.
I got lucky and was able to get all the parts for a 3dprinter. I’m building an OB1.4 with a few mods. Everything is here but my plastics and beams and those will be here when they are finished printing. It is going to be really nice being able to print cases for electronics.
I got the first and second ones together. The first is a compact with a radio soldered in. The second has the radio on a socket so I can test radios when I get them. Both worked on the first try, the first quickly got weird and started locking up. I managed to track it down using the Fail-Safe clock monitor. One of the caps is a bit too close to the crystal so once its all done I hit it with some hot air and the problem was gone. When I post up the files I will have fixed that. It is fine, just needs to be done carefully the way it is.
Playing with the hot air I came up with a nice technique to get the results pictured above. I used a piece of scotch tape to secure the chip and tack it down. Place the chip, hold it down with a finger. Place tape on chip, nice and flat so it can grip the chip well, while holding the chip with a thumb nail. Inspect placement before even heating the iron. I actually took 3 trys to get it placed in the picture. Once it looked perfect tape it down and inspect it. There should be one side with all the pins exposed. Tack one pin being really careful to only get one pin. Remove tape and inspect. If it is not perfect adjust it after wetting that pad you tacked. Get it perfect.
When it is perfectly even on every corner, each pin is in the middle of its pad all the way around, Put lots of flux on. A fume extractor pays off. I had a nice headache after I finished the first one. With a nice clean iron tip, wet nicely, Drag a nice bead of solder over the entire exposed side being careful not to move it. All or most of the pins will short , but you will be able to quickly get every pad and pin taking solder since the heat transfers well with a nice bead of solder on the tip. Then get some solder braid and take as much solder away as you can with out burning up the board. If you inspect the results with a microscope it looks hairy, with tiny unseen bridges all over and in seemingly hard to reach places behind pins. Take out the hot air station, set it to 300c and get all the pins to temp and all the messy hairs pull into nice looking pads. Q-tips with alcohol clean up the board nice after. It is way faster then trying to get each pin. Just be careful not to solder your braid to the board. In the end it looks better and takes the precision out of the process and lets physics do the hard work.
I have two of these working now.So far every thing is tested, working. It has a usb bootloader and is ready to be configured via virtual comport that it functions as when not in bootloading mode.
It is worth noting I learned you want to use hot air sparingly. I seem to have fried a via and it became a 90k ohm resistor instead of a via. Luckily it was the power rail so it was easy to spot and fix with a resistor lead. Basically you want to keep the air moving all the time and not focus it.
I picked up a Blinky Grid from Wayne and Layne to test my soldering before going at the telemetry boards. I figured I would use this as an opportunity to review both the product and the service at http://www.wayneandlayne.com where I purchased the kit from. I was not paid to do this nor did I receive a free kit I paid for it just like any other customer. And it is also worth noting that because of a car wreck I was in my hands shake really bad so my being able to solder this probably means you can too.
I inquired about a blue version of the Blinky Grid. The guys were awesome, prompt, and although they don’t carry a blue SMD version because the leds alone cost like 35$ they were really helpful. The item shipped quickly and got here really fast. The shipping was also really affordable.
Kit and assembly:
The kit went together remarkably easy with the exception of the PIC. The pads seemed a little small but it went together and works on the first try. You should definitely get a pair of tweezers designed for SMD work with a nice sharp point. Adafruit sells the pair I have. Take your time! Use a bowl when you take out the parts. Also you need really good light. The PIC was the only part I found to be difficult at all. It took me about an hour to assemble. Also worth noting is you will need a 2032 coin cell to power it when you are done. It is not included. The website instructions for assembly are great and should be followed. I found no issues with them.
I used some scotch tape to hold the pcb to the desk while soldering. I did each row of leds one at a time from top down working from the opposite side of the hand I held the iron in and working my way back towards me. I rotated the board so the pad I was working on faced towards me so I flipped it once per row. Folding over on edge of the tape so it comes off the desk easily makes it easy to do. Check the green dot on the led before soldering the other side.
Overall I was surprised how easy this was. Even with my shaking hands it worked on the first try. I can suggest this kit for any one who wants to try SMD soldering. My humble opinion is “If I can do it any one can”. The kit is a deal for what they ask for it. And programming it with your own messages or animations is a breeze. I am really impressed with this kit, and the service at http://www.wayneandlayne.com
The web site has the kits, the instructions for assembly and the programming site to change what is displayed. All of them are quite easy to use. Their website is in the middle of an upgrade as this is written.
Here are the v2.1 files for the drawbot Ive been working on. (The files are below) Special thanks to Laen from http://dorkbotpdx.org/wiki/pcb_order for the help learning to export gerbers and check them with GerbV.
This was inspired by trying to help a friend with some hardware issues with the Makeitlast contest #3. It just turned into a project after all the work that went into it
“Released under the Creative Commons Attribution-ShareAlike License (3.0)”
Thanks to Adafruit for getting me threw the legal jargon for the stuff above.
confirmed working. THE POWER SUPPLY IS TIP POSITIVE ! there is no reverse current protection.
Schematic I should mention just use 1uf ceramic caps I think I messed up their values in the schematic.
Parts list with digikey P/N where available
Board readme This document pertains to an upcoming release of a new firmware and the DBC app. Key mappings are not the same as the firmware below. 10/14/11
quick assembly tips:
- Don’t forget to connect the grounds above the LDO (seen in picture above)
- Put sockets on the PIC, eprom , not the hbridges.
- The led, the flat side is the bottom , if the pcb silk screen is right side up. It is marked with a line.
- PIC pin one faces up . eeprom pin one faces down.
- Solder the ICSP right angle header from the bottom so the pin one indicator is visible as seen above .
- The led will NOT light when power is applied to the (UN-programmed) board , it is not a power indicator but rather a debug led connected to an io pin , controlled by firmware.
Applications to use the drawbot
Picture Decoder by Colin Faulkingham (MIT license see source code)
Drawbot control app v1 by Jayson Tautic for v1.0 precompiled hex below
Current version 1.0 precompiled hex
The files below are an upgrade to the version 1.0
They do not work properly with Drawbot control at this time.
PIC Firmware first version 1.x
Pre-Compiled hex file (1.x )
pixels used below
It is interesting to me, no one commented on the Right side , how the first line ends , it goes up (and over an extra pixel width each time) .
Here is a short demo of the v2 greenwire board half mounted and working. It has since been mounted to the wall with the motors 6 feet across
Fast Tube by Casper
If you don’t play Darkfall then you probably have no idea what this is. In Darkfall they make you do things like ride a horse for a really long time to skill up the skill riding. Pretty much every thing in the game can be done repetitively to make your character better. This is /not/ fun .
You can ride a horse into a wall and go watch a movie but people always come and kill you and steal your horse. Tons of people do this swimming into docks or walls so they dont randomly run into some one and get killed.
I used a TAUTIC PIC18f14k50 break out board , and the Microchip mouse in a circle demo to make a ‘mouse makes you swim in a circle’ program that does exactly what it says. It makes your mouse move to the right at a constant speed so you can run a swimming / diving / riding etc macro on your favorite macro program and do it out in the middle of no where. This means you can run a pretty effective macro and not worry about your town getting rolled and you dieing.
To use this with the TAUTIC PIC18f14k50 break out board press the button labeled RA3 and hold it while inserting the USB cable. This .hex file can be loaded into the breakout board using the bootloader it comes with and the accompanying bootloader pc side app found in the microchip applications library under the HID boodloader folder. Im sure if you buy one and ask him to load this firmware he would be happy to ship it ready to go.
When you plug it in it is seen as a mouse. RA3 switch toggles the continuous mouse movement to the right on and off. Which keeps you swimming in a circle out in the middle of no where safe.
Ps dont worry, this is not usable for PVP, ie using it to run in circles while dueling. I intentionally coded it so its not going to give any advantage in this situation. All this is useful for is afk macroing.
It will have to be unzipped in the root directory due to its names size. ( c: )
Program flow diagram
Disregard previous schematics. I will post updated ones soon.
Parts list to come
Video (using my new camera from Digikey! Wow this camera is nice Thank you again! )
All of the EEPROM code is in , few little things to work on still, like a quick press to the button writes a page of nothing if the logger is not on. It should do nothing in this case.
I noticed a few projects with nearly the same schematic as this so I thought I would get the code up.
When I have had some coffee , I will put up some features here. And probably a video demo later this after noon.
- half second intervals (RTCCalarm)
- One button interface hold till led blinks to indicate logging, or quick press to terminate logging.
- Interrupt driven logging.
- Page writes
- Scans for data on startup. (searches for 255 in block zero of a page) Doesnt lose data with loss of power.
- Logs temperature
- Grounding issue resolved , consistent measurements now
- Still needs calibrating
- Blink on time with the half second bit of the RTCC
- Although the mapping is off, they are finely tuned to the control I have
- ECCP driven PWM capture
- Also used for indication for logging
Shell commands (hyperterminal etc)
- Various test and debug commands
- Clear all used memory (c)
- Download Datas (d)
- Make fake datas (m) Saves time since the logging rate is fixed.
- Next address (n)
- Previous address (p)
- current Address (a)
- A quick press to the button writes a page of nothing if the logger is not on
- My pickit 3 doesnt like this board. My pickit2 works fine if the board isnt powered. The problem is the Buss sense pin which is one of the ICSP pins.
- If you turn the transmitter off , and have the servo battery on, and connect it to usb it hangs. You should turn the logging off, then turn the servo battery off, at the track. Then just plug into USB from 100% off . It will be powered from the USB and not power the receiver so its safe to download datas in the pit. It can run off of both at once no problem, if the transmitter is powered on.
- This code utilizes only the first bank of memory. Half of the memory chips capacity is still brand new if the EEPROM endurance ever fades.
- Ive got the wrong diodes right now. If your using the ones I have they are not correct. I will post the right ones with the updated schematic. The diodes work but seem to stop at half battery power.
- Interrupt time outs on steering and throttle reading functions. (Thanks @monpjc for the suggestion)
- Fix above
- Power saving , which hasnt even been considered yet, these cars have nice rechargeable batteries
- Id like to see a simple Processing app , that is made specifically for this.
- Couple lines of code so it doesnt download empty memory blocks between logs
- Add line of code to stop logging when usb is detected incase some one leaves it on.
I read the manual now , figured out every thing I had any trouble with (manual passes its test). Now Ive changed out all the generic parts for the ones I was originally using and fixed up the ground issue. Its all in the details here. All the labels are proper , well unless I missed one. The “to”s are in and properly labeled. It turns out if you read the manual it explains every thing in an easy to follow tutorial. The searching isnt as bad as it first appeared also. The manual shows some methods to speed things up considerably .
I am pretty impressed with this.
Ps I forgot the zero ohm resistors. There is a great explanation why to have them HeRe.
Almost ready to post a legitimate first revision.
I woke up today and started working on fixing my ground issue. But I wanted to show what 8 hours with a program I installed yesterday at like 5am got me. I figured out every thing except how to make my ground and 3.3 symbols connect to the inner planes. Still working on that.
Working with eagle was counter intuitive. Tutorials brute forced me threw setup, and threw the counter intuitive interface (thank you sparkfun and adafruit) but after a few weeks of using it I still find my self doing things like pressing delete to delete things and that just isnt how eagle works. Of course this is only one very small example but thats not my goal here to rip on eagle. It is powerful.
I decided to check out Designspark PCB 2.0 yesterday at 5 am. I was caught off guard by the intuitiveness of the design. For instance the tutorials to import Eagle files that you would expect to be nestled away in the web site is distributed with the program and is accessible from the help menu. This was actually so intuitive it caught me off guard and I spent a good 25 minutes searching the web for it. Now please note I was making a point NOT to read instructions , quick start guides, tutorials, or the forums . I wanted to see how easy to use it was , not test my researching abilities.
Within 2 minutes of finding the tutorial I was on my way. And when I press delete it deletes!!! Shortly after my schematic and libraries were in and All was well. So I deleted my files and started over from scratch. Keep in mind the ONLY thing I read was the Importing eagle tutorial.
It took me no time at all to figure out the interface. Im already able to do more then I was in eagle. Most every thing is intuitive and once you understand it from playing with it things come naturally.
This has some serious potential. This is something I recommend trying and becoming involved in the development of. This is a prime example of crowd sourcing working.
Here is a link to the official page for Designspark PCB 2.0 did I mention its free?
There is also a second post after reading the manual, which is very well written and explains every thing very well.
I think its worth noting because the fine details that Ive never gotten right in eagle are coming together well. On even playing ground there really is no competition which app is easier , more intuitive. Designspark PCB wins hands down.
I was unable to rework the Microsd jack on my remaining boards. The Card detect line is mixed up in the code. It reads the card fine if its inserted when its plugged in but removing it causes issues. I sent out my working board thinking I had this fixed and I was wrong and now wont be able to fix it and test it. I am planning on redesigning this board using eagle for the files , and using PIC18f46j50 and rotary encoders (lighted).
This code is rather embarrassing. Ive been meaning to write some functions so it wasnt so inefficient in how it handles the pots . But with the failed boards I will be holding off on rewriting it until I can afford another run of pcbs. This is going to be a while so here it is.
The switches are a bit off in footprint . Also the resistors are a bit small they go in at an angle. HIGHLY recommend using different micro sd jack then I did. That thing is hard to get assembled. 2 in 4 success rate here. Keep checking back I was planning on rewriting this and kicking off a git account with it but it will be a while before I can get to it now. As embarrassing as the code may be , it works if the card just stays in all the time.
I made this so people could be inspired to make something and with MPLABx and other developments not to far off the relevance of this will be less.