I'm an avid R/C modeler, and I'm just finishing up my latest 'winter building' project, a 150" wingspan Douglas DC-3! http://http://en.wikipedia.org/wiki/Douglas_DC-3 I wanted to add a continuously flashing strobe light on the vertical stabilizer of the airplane, and remotely controlled Red (left) and Green (right) navigation lights on the wingtips. To satisfy this need, I decided to 'roll my own' R/C Aircraft Lighting Controller to finish off my DC-3 airplane!
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This design is based on the PIC 12F629 microcontroller. The code for this project is written in 'C', using the CCS 'C' compiler. The schematic and board were done using Cadsoft Eagle software, and the PCB fabrication was done by OshPark!
The code is pretty simple. Timer0 in the PIC is used to generate the continuous 'Strobe' output signal of 2 seconds Off, 0.3 seconds On. Timer1 is used to measure the incoming pulse width of the R/C signal. This pulse width varies between approximately 1.0mS and 2.0mS, representing servo position and repeats at approximately 50Hz. My code switches the 'Nav' lights On at pulse width of approximately 1.5ms, with some hysteresis to prevent flickering about the trigger point. The code also will detect when the R/C input signal is (1) lost, or (2) intermittent, and will flash an error code using the Nav lights.
I'm looking for someone that can design an on-line membership application for a club I belong to. The application needs to be somewhat dynamic so that it 'populates' correctly depending on the type of application (New or Renewal - selected with a radio button). The application also must be 'aware' of the date as the dues amount is pro-rated based on the join date. Once an application is complete, PayPal will be used for billing.
I currently have a couple of static pages doing this membership function, but I'd like to clean it up and stream-line things a bit! I'm NOT looking for a freebie here, and am quite willing to discuss some sort of compensation if you are interested. Perhaps you'd like something from SEEED, Sparkfun, or Adafruit?
I'll send more details to anyone interested in taking a look at this project!
I'm looking for someone to code a single webpage for me that will be a member sign-up form for a model airplane club I'm involved in. I've already got a pretty functional page doing this using FrontPage, but it's clunky, and I'd like to add some dynamic content (example: membership dues change depending on sign-up date, etc.). Basically, I want something that is more functional, and looks more professional. If you are interested in this project, we can work out some mutually agreed upon payment, such as a credit at Sparkfun, Adafruit, or SeeedStudio, etc.
Contact me via PM, and then we can continue via email!
Here is my latest project, a 'GPS to Xbee Bridge'. This project utilizes a USGlobalsat BR-355 GPS receiver, and an Xbee module to wirelessly transmit a GPS-derived time/date info packet to a variety of home-brew clocks around my home! These clocks consist of an odd mix of Nixie Tube clocks and GLCD clocks that I've design and built over the years! The design is based on a PIC 18F14K22 processor which receives and parses incoming NMEA data from the BR-355 GPS module, and an Xbee or Xbee Pro wireless module. These packets are transmitted every 15 seconds!
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The prototype for this project looks pretty good, however, I made a pretty glaring mistake in the initial design by omitting an RS232-to-TTL converter IC between the GPS and the PIC! I hot-glued a MAX3232 IC to the back of the board deadbug style, and ran all my wires on the backside. Of course, the final PCB version will include this IC! The board itself is a 'Sick of Beige' size format, and will be mounted thus once complete!
Prototype boards were sourced through the awesome OSHPark service!!
I've been running Cadsoft Eagle v5.12 with a hobbyist license for the past year or so. I've resisted "upgrading" to Eagle v6 because the current version is basically doing everything I need. Lately, however, I've been encountering libraries and designs that I cannot open because they are in the v6 format. Aside from cost, are there any reasons not to "upgrade" to Eagle v6?
I'm looking for suggestions for an assembly house that will do "prototype/beta quantities" (about 25 pieces) at a "reasonable" price. This is for an all surface mount project (about 30 components total) that is actually quite easy to hand solder except for a fiddly (0.5mm pitch) GSM modem connector. I'd be happy to just send Gerbers and a BOM, or I can provide the boards and parts. At this point, price is the critical driver. Location is not terribly critical either. I'm in the US, so that works, but Asia and Europe are also fine.
I've emailed Seeed and iTead several times, but neither has replied to my email, so I gather they are not interested.
I'm currently working on a couple of clock projects, and I wanted to have a reasonably accurate time standard to set them, so I put together this quick project, a GPS Display/Time Standard.
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This board uses a GlobalSat EM-406 GPS engine, a PIC 16F689 MCU, and an 8x2 LCD display. The board is intended to be powered externally for stand-alone operation, or by the attached clock. Time data is output to the clock via a 4 pin MTA connector. The firmware will display the number of "locked" satellites on power up, and then revert to time display mode as soon as a valid position/time is received. Time display can be in 12H or 24H format, and a programmable UTC offset can be set to display "local" time if desired.
This project is not intended for ultimate time setting accuracy, but should deliver sub-second (< 1 second) accuracy, which is good enough for my needs.
Several weeks ago I won one of the three Cadsoft Eagle "Hobbyist" licenses given away by DP! Thanks to DP, and especially to Cadsoft, for their support and generosity!
I won the license based on my desire to design an Open Source Nixie Clock, and I plan to share that design here in the DP "Project Logs" forum! I've been working on this design for a couple of months, but was forced to put it on the shelf due to the board size limitations imposed by the "free" version of Eagle. With the free version, my "tube board" design would only allow space for 3 of the 6 tubes I intended to use!
Over the next week or so I'll be posting the preliminary schematics, parts lists and board files for the design. I'll also be discussing the overall structure and design of the firmware. My intention is to make an initial prototype using the 'DorkbotPDX' PCB service, and then have the final boards make at Seeed. I'll probably get extra boards, so anyone that needs one will not have to order their own, but can get one from me. The firmware for this project will be written in 'C' using the CCS 'C' compiler, although the code should be fairly transportable to other compilers. I do plan to leverage a lot of the hardware design, and firmware from my recent GLCD clock project covered here earlier.
My design will be based on the 'IN-14' Nixie tube. These tubes are an excellent size for clocks, and can be readily purchased from sources on eBay for about $7 USD per tube. The design will feature six of these tubes, and two neon "colon" digit separators. The design will feature separate 'clock' and 'tube' boards, so other tubes can easily be supported!
Nixie Clock Design Features
(6) IN-14 Nixie Tubes 18F2550 Microcontroller with USB +12V DC Input (Wall Wart) Maxim DS-3234 RTC with TCXO Battery Backup Time Setting via USB or On-board Switches Power Down Mode (Increase Tube Longevity) Anti-Cathode Poisoning Mode (Increase Tube Longevity)
I've designed a hardwood base for Nixie Clock I've got in mind, and I've selected an acrylic display case to go over it. Once complete, this clock should have a very 'professional' look and should be worthy of display in a prominent location in your home!
If anyone else would like to help, or has some other ideas for design features, please feel free to chime in!
I thought I'd share my latest project with everyone, a Cellular Remote Control. This project is intended to allow me to remotely activate two AC outlets that will be used with an aircraft engine pre-heater. During cold weather, air-cooled aircraft engines should be "pre-heated" to help with starting, and to reduce engine wear during the start phase. Each cylinder on the engine is fitted with a resistive "band heater", and the oil sump is fitted with a "pad heater" totaling about 750 watts. There is also a small ceramic heater inside the airplane used to warm the cabin. I don't like to leave the heaters on continuously, but rather switch them on the night before I plan to fly. I've been remotely controlling these heaters for several years with a ham radio based controller, but thought I'd update the design, and add a few features!
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This project is based on the PIC 18F2550. I chose this PIC because it is USB-capable, and I plan to use a USB bootloader for easy firmware updates. The project also utilizes the ADH8066 Quad-Band GSM Cellular Module for all communications. The module is activated on a cellular network by installing a "SIM" card into the holder on top of the module. I use a "pre-paid" cellular account from T-Mobile with this module, and so far it has worked flawlessly. In addition to the remote switching function, this project also has an on-board temperature sensor that will allow me to remotely monitor the temperature in my hangar, and to automatically notify me when the temperature goes below, or above, certain preset limits.
The AC relays for my project are separate from the board shown above. I wanted to keep all the AC connections isolated from the low voltage circuits for safety reasons. There is a RJ-45 connector on the board that will drive the external relay board. I'll post a picture of that when I have it completed!
I came across this site recently, and figured it would be of interest to a lot of folks here on DP. Even if you never intend to build one, this project gives you a lot of insight into the inner workings of GPS receivers.
I've got an 18F2550 project that yearns for a bootloader! I'm thinking that the bootloader that has been used on a number of DP projects will fit the bill nicely. To integrate such a bootloader into my project, are these the steps I'd take?
1. Program my board with the bootloader .hex file using ICSP. 2. Relocate the start of my program to the "application memory" area pointed to by the bootloader, and recompile. 3. Use the bootloader to install my application firmware. 4. Test
If this is basically the roadmap, a couple of questions come up. It's not clear to me from browsing the bootloader source exactly where in memory the bootloader jumps to run the application program. IOW, how far must my application code be offset in order to accommodate the bootloader? Are there any other changes necessary to my application code?
When I eventually get this to work, are there tools available to "merge" two hex files into one to allow combining the bootloader and the application into one .hex file?
It appears that the PC side uses 'fw_update.exe' to manage the bootloading process. Is there a GUI available to do this, or is it strictly command line?
I just got the prototype boards back for my latest project, a DC power supply monitor with GLCD display! This power supply monitor is intended to measure the voltage and current of a DC power supply, and continuously display these values on a 128X64 pixel LED backlit GLCD display. A PIC 16F876A micro will be the "brains" of this project. Some unique features of the design include a switch mode power supply for inputs up to 30V, and an on-board 4.096V reference.
This project will be used with a commercially available power supply made by the Astron Corp. that is used as a ground power supply (GPU) for a general aviation aircraft. The power supply is used to operate the airplanes electrical system when the plane is on the ground undergoing tests. Monitoring system voltage and supplied current is important in this application.
The power supply voltage is scaled for the A/D input by a solder-selectable jumper (12V or 24V), while current is measured by an off-board Honeywell hall effect sensor.
I've got most of the firmware written for this project using a hand-wired prototype as a test-bed, so now it's time to build the real thing, and see how it works! I'll post some assembly pictures, and pictures of the power supply monitor in operation once I have it complete.
For the past year I've been using a solder with a water soluble flux to assemble all my prototypes. I love the fact that I can get a squeaky clean board with just a toothbrush and a little bit of warm water. Previously I had to use a rosin flux solvent and an ultrasonic cleaner to get my boards this clean!
Last week, however, for the 2nd time in the past year, I've had a problem related (I think) to the water soluble flux. In both cases, the crystal oscillator on a PIC based board failed to start due to trace amounts of flux residue remaining on the board. In each case, a vigorous cleaning of the board made the problem go away completely! It took quite a while to solve this issue the first time, and about an hour the second time when I suddenly realized I'd already seen this movie :-)!
So, I still really like the convenience of the water soluble flux solder, I'm just reminded that the board needs to be extra clean after using it!
I just got the prototype boards back for my latest project, a GLCD Clock! This clock will utilized a 128X64 pixel LED backlit GLCD with the KS0108B controller, and time-keeping will be controlled by a battery-backed Dallas DS-3231 RTC. A PIC 16F876A micro will manage the whole show. Two pushbuttons will be used to set the various display modes (digital clock, or watch face clock), and set alarms, etc. An input is also provided to 'sync' the time using a GPS receiver with RS-232 output.
I've got most of the firmware written for this project using a hand-wired prototype as a test-bed, so now it's time to build the real thing, and see how it works! I'll post some assembly pictures, and pictures of the clock in operation once I have it complete.
I'm looking for some ideas on how to protect a PIC input pin that will be exposed to the "outside" world.
I'm building an 'event counter' that will count contact closures on the PIC input pin. The user will supply their own external switches/wiring, so this input should be fairly robust. I'm hoping to do this with simple discrete components (I only need a single input, so an IC would be overkill).
I was thinking about a couple of diodes on the input wired to the +5V and Gnd rails, and maybe a transorb surge suppressor to Gnd. Will that be sufficient? Does anyone have a favorite circuit for this application?
